ABC Online

NASA flags lunar commerce. 29/04/2006. ABC News Online

[This is the print version of story http://www.abc.net.au/news/newsitems/200604/s1626715.htm]

Last Update: Saturday, April 29, 2006. 2:44pm (AEST)

The strategy workshop has been the first of several scheduled for this year that aim to set out specific goals for future space missions to the moon and Mars. (Reuters)

NASA flags lunar commerce

NASA says making money on the moon is an essential part of the US plan for space exploration, following a four-day strategy workshop with international space officials and scientists.

The gathering has been billed as the first meeting to determine what explorers would do if they return to the lunar surface after more than three decades.

It has drawn 180 participants from more than a dozen countries, including China, Russia, Japan and the nations of the European Space Agency (ESA).

NASA deputy administrator Shana Dale says one clear goal is to do business.

"The teams recognise the critical importance of space commerce - having real companies going to the moon and making money," she said.

"The [US] Government needs to be a trailblazer and enabler [with] a desire to see commerce take off."

She says other essentials for a global space strategy include public involvement and participation by international partners.

Lunar law

The working groups have also noted the need for lunar law early in the process.

NASA Jet Propulsion Laboratory spokesman David Beatty says an international legal framework would be helpful in the area of property rights, interoperability standards and making hardware from various countries work together.

NASA Goddard Space Flight Centre spokeswoman Laurie Lesin says such laws could govern more prosaic issues as well.

"At our group, we did mention once briefly how we're going to decide which side of the road we drive on, on the moon," she said with a laugh.

Space vision

The strategy workshop has been the first of several scheduled for this year that aim to set out specific goals for future space missions to the moon and Mars.

US President George Bush outlined the plan in a sweeping "Vision for Space Exploration" in 2004.

Delivered less than a year after the fatal 2003 shuttle Columbia accident, Mr Bush called for a human return to the moon by 2020 and eventually a human flight to Mars.

Since the Columbia disaster, in which seven astronauts died, only one space shuttle has flown, and the shuttle fleet is to be retired by 2010.

A new Crew Exploration Vehicle, meant to return humans to the lunar surface, is still on the drawing board and may not be ready until 2012 or later.

- Reuters

© 2006 Australian Broadcasting Corporation

 [ send green star]

 

ABC Online

Gravitational 'dance' behind planets' tilt. 27/04/2006. ABC News Online

[This is the print version of story http://www.abc.net.au/news/newsitems/200604/s1624616.htm]

Last Update: Thursday, April 27, 2006. 6:28am (AEST)

Gravitational dance: The axis of Jupiter has been influenced by the other planets. (Reuters)

Gravitational 'dance' behind planets' tilt

An early gravitational 'dance' made the giant planets tilt in a way which is different from the way Earth and the other smaller planets tilt, an astronomer says.

Adrian Brunini, of the Facultad de Ciencias Astronomicas y Geofisicas in Buenos Aires, says the shift probably happened billions of years ago when the bigger planets in our solar system were closer together than they are now.

He says the gravity of each one exerted a pull on the others.

Mr Brunini says this "neutral gravitational interaction" caused Jupiter, Saturn, Uranus and Neptune to have tilted axes that were determined as they moved through the solar system to take their current positions far from the Sun.

This is a departure from an earlier theory that holds that the massive planets' tilts - or obliquities, as astronomers call them - were caused by collisions with earth-sized space rocks during the early period of the solar system.

"This model has some problems that were not clear how to solve," Mr Brunini said.

"For example, we believe that such a big object never existed in the outer solar system."

Numerical models

In research published in the current edition of the journal Nature, Mr Brunini uses numerical models to show that the outer planets' obliquities could have been created by gravitational interactions.

All the planets in our solar system have tilted axes but the bigger ones have axes that lean at a constant angle, while the smaller ones like Earth have obliquities that can change.

Despite the potential for change, Mr Brunini says Earth's axis has been leaning about 23 degrees for millions of years and is almost completely stabilised by the moon's gravitational pull.

But he says Mars' axis might change over tens of millions of years.

For humans, the reliability of Earth's tilted axis is important since it is responsible for the change of seasons.

At the point in its annual orbit where earth's Northern Hemisphere leans away from the sun, it is winter; when the Southern Hemisphere tilts away, it is winter there.

Mr Brunini says while the more massive planets have stable obliquities, they range in size from a nearly perpendicular three degrees for Jupiter to about 97 degrees for Uranus.

- Reuters

© 2006 Australian Broadcasting Corporation

 [ send green star]

I loved all the info.   This stuff really interests me.   I recognize some faces in this group, friends and friends of friends

 [ send green star]

By Paul Rincon
BBC News science reporter, St Louis

Not all of the billions of stars can be examined by scientists

An US astronomer has drawn up a shortlist of the stars most likely to harbour intelligent life.

Scientists have been listening out for radio signals from other solar systems in the hope of detecting civilisations other than our own.

Margaret Turnbull at the Carnegie Institution in Washington DC looked at criteria such as the star's age and the amount of iron in its atmosphere.

Her top candidate was beta CVn, a Sun-like star 26 light-years away.

Dr Turnbull had previously identified about 17,000 stellar systems that she thought could be inhabited.

From these, she has selected five stars that look most likely to support intelligent extraterrestrial life forms - if they exist.

"I've chosen five to advertise the very best places to move to if we had to, or to point the telescope at," she told the BBC.

 [ send green star]

These extremely massive stars are tremendously hot and bright and have very strong winds, making the job of building planets difficult," said Joel Kastner of the Rochester Institute of Technology in New York. "Our data suggest that the planet-forming process may be hardier than previously believed, occurring around even the most massive stars that nature produces."

Kastner is first author of a paper describing the research in the Feb. 10 issue of Astrophysical Journal Letters.

Dusty disks around stars are thought to be signposts for present or future planetary systems. Our own sun is orbited by a thin disk of planetary debris, called the Kuiper Belt, which includes dust, comets and larger bodies similar to Pluto.

 [ send green star]

No one has ever seen a black hole, but astronomers study the way matter and energy behave around them. (NASA/Reuters)

 [ send green star]

Consider also the following astute insights of Rep. Dana Rohrabacher (R-Calif.) in a House speech entitled, "The Reality of 'Global Warming'", which he presented on June 12, 2001:

". . . global warming is not a scientific imperative. It is a politically-driven theory. . . .

How about water? Water comprises three-quarters of the world. Given the sheer volume of water on this planet, it surely has a tremendous impact on the temperature of the air. However, there are no accurate global ocean temperature readings that go back more than 10 years, and those that do are primarily based on satellite observations of surface temperatures. Those readings do not include deep water. In fact, we have absolutely zero understanding of deep water temperatures, and almost no understanding of deep water ocean currents. How can we possibly ignore that data when trying to calculate something as overwhelming as global warming? Global warming studies did not take into consideration the ocean temperature, and sometimes when they did it did not give them the right facts, so they just went on to something else. . . . most of the sources for CO2 and the other so-called greenhouse gases are naturally-occurring and not manmade. . . . Volcanic activity, for example, can add more to the atmosphere in a few weeks than all the internal combustion engines on this planet over the last decade. Termites and other insects, for example, are such a large source of CO2, and it [sic] is a larger source of CO2 than all of the industrial plants in the civilized world. Rotting wood is another offender that dwarfs any human contribution to this so-called threat.

I do not hear many calls coming from the people talking about global warming to bulldoze the rain forests. If they really believe in global warming, the rain forests, the rotting wood and the insects in those rain forests are the worst contributors."

 [ send green star]

Happy Pearl Harbor Day. FDR knew it was going down and he knew his buddies would get rich.

 Guilty as charged, your Honor.

 [ send green star]

Jets of fine, icy particles streaming from Saturn's moon Enceladus were captured in recent images from NASA's Cassini spacecraft. The images provide unambiguous visual evidence that the moon is geologically active.

"For planetary explorers like us, there is little that can compare to the sighting of activity on another solar system body," said Dr. Carolyn Porco, Cassini imaging team leader at the Space Science Institute in Boulder, Colo. "This has been a heart-stopper, and surely one of our most thrilling results."

The Cassini images clearly show multiple jets emanating from the moon's south polar region. Based on earlier data, scientists strongly suspected these jets arise from warm fractures in the region. The fractures, informally dubbed "tiger stripes," are viewed essentially broadside in the new images.

The fainter, extended plume stretches at least 186 kilometers (300 miles) above the surface of Enceladus, which is only 186 kilometers wide. Cassini flew through the plume in July, when it passed a few hundred kilometers above the moon. During that flyby, Cassini's instruments measured the plume's constituent water vapor and icy particles.

Imaging team members analyzed images of Enceladus taken earlier this year at similar viewing angles. It was a rigorous effort to demonstrate that earlier apparitions of the plumes, seen as far back as January, were in fact real and not due to imperfections in the camera.

The recent images were part of a sequence planned to confirm the presence of the plumes and examine them in finer detail. Imaging team member Dr. Andrew Ingersoll from the California Institute of Technology in Pasadena, said, "I think what we're seeing are ice particles in jets of water vapor that emanate from pressurized vents. To form the particles and carry them aloft, the vapor must have a certain density, and that implies surprisingly warm temperatures for a cold body like Enceladus."

Imaging scientists are comparing the new views to earlier Cassini data in hopes of arriving at a more detailed, three-dimensional picture of the plumes and understanding how activity has come about on such a small moon. They are not sure about the precise cause of the moon's unexpected geologic vitality.

"In some ways, Enceladus resembles a huge comet," said Dr. Torrence Johnson, imaging team member from NASA's Jet Propulsion Laboratory in Pasadena. "Only, in the case of Enceladus, the energy source for the geyser-like activity is believed to be due to internal heating by perhaps radioactivity and tides rather than the sunlight which causes cometary jets." The new data also give yet another indication of how Enceladus keeps supplying material to Saturn's gossamer E ring.

The Cassini-Huygens mission is a cooperative project of NASA, the European and Italian Space Agencies. JPL, a division of the Caltech, manages the mission for NASA's Science Mission Directorate. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute. For the latest Cassini images on the Web, including a time sequence showing the plumes, visit:  [ send green star]

A Japanese spacecraft has successfully landed on a far-away asteroid for a second time and almost certainly collected the first samples from such a celestial body, says Japan's space agency.

The Hayabusa probe is on a mission to bring back material from the Itokawa asteroid 290 million kilometres from Earth to help scientists learn more about how the solar system was created.

It could also provide vital information about the composition and structure of asteroids for any future efforts to deflect a celestial object on a collision course with Earth.

The US and the former Soviet Union have brought back samples from the Moon in the past, but this is the first time that surface material from an asteroid is believed to have been collected.

The unmanned craft fired a 5 gram metal ball at the asteroid's surface to stir up material for collection and the operation went "without failure", says a spokesperson for the Japan Aerospace Exploration Agency (JAXA).

"As this asteroid was estimated to have emerged roughly 4.6 billion years ago, when the solar system was created, the samples could be something like fossils of the solar system."

Resarchers will not know for sure whether it picked up surface material until the craft returns to Earth in 2007, after travelling a total of two billion kilometres. But they say they are confident it worked.

Nothing's certain
"I'm sure we could collect samples," says project manager Professor Junichiro Kawaguchi, although he adds he needs more circumstantial evidence to say with certainty that the attempt was successful.

"We have overcome the biggest challenge in the project."

The mission was all the more difficult because the potato-shaped Itokawa asteroid, 540 metres long and 270 metres wide on the larger end, is revolving and has very low gravity.

This makes it tough for Hayabusa, named after the Japanese word for falcon, to land on a targeted site such as a flat area on the jagged surface.

 [ send green star]

Hayabusa is designed to gather space dust for return to Earth

The planned touchdown on an asteroid by a space probe has been postponed.

The Japanese Aerospace Exploration Agency said it had received an "anomalous signal" from the craft shortly before it was due to make its descent.

The Hayabusa spacecraft was launched in May 2003 on a mission to find out more about the raw materials that made up the early Solar System.

On Friday, it was due to land a robot on the surface of asteroid Itokawa.

Robot passenger

The 10cm-tall Minerva robot is designed to bounce across the surface of an asteroid, collecting temperature readings and images.

The asteroid is named after Hideo Itokawa, a father of Japan's space programme

 [ send green star]

View from one of Pluto's candidate new moons. Pluto is the largest object in the sky, its confirmed moon Charon is to the right. The tiny object on the far left is the other candidate new moon (Image: NASA, ESA and G Bacon/STScI)

Pluto, that cosmic oddball at the far reaches of our solar system, may have three moons instead of one, scientists say.

Astronomers using the Hubble Space Telescope glimpsed the two new satellites back in May, and were intrigued when the pair of possible moons appeared to move around Pluto over three days in what looked like a nearly circular orbit.

If confirmed by the International Astronomical Union, they will get official names based on classical mythology, joining Pluto's moon Charon, which is named after the ferryman of the dead. Pluto is named after the lord of the underworld.

For now, the new satellites are called simply P1 and P2. One of the scientists who discovered the satellites couldn't resist making some spooky allusions with the announcement, which was made on Halloween.

"It's ... strictly coincidental that Pluto of course was named for the god of the underworld and we're describing these Halloween moons," says Dr Alan Stern of the Southwest Research Institute.

After Charon
Pluto's first known moon, Charon, was discovered in 1978. Charon is about half Pluto's size, making it less like a satellite and more like a sibling.

Many scientists consider Pluto and Charon to be a binary system, with the moon orbiting about 19,400 kilometres from the planet.

The newfound putative satellites are likely much smaller than Charon, ranging in size from perhaps 48 kilometres to 161 kilometres in diameter.

Scientists are still trying to figure this out.

Charon is about 1200 kilometres across, and Pluto is about 2300 kilometres across.

The discovery of the two additional satellites means Pluto is the first known object of the Kuiper Belt - a ring of rocky debris circling outside Neptune's orbit - with more than one moon, says Dr Hal Weaver, of the Johns Hopkins UniversityApplied Physics Laboratory.

Is Pluto a planet?
But the new finding does little to clear up Pluto's planetary status. While it was discovered in 1930, Pluto has such an eccentric orbit around the Sun that some have questioned whether it deserves to be called a planet.

The International Astronomical Union, which considers such matters, calls it a planet, but the specific definition of what constitutes a planet is under review.

Mere multiple moons do not change Pluto's status, according to Stern, who serves on an astronomical panel that is working on the new definition.

"Whether or not an object has a moon is not part of the criteria that we've considered, because so many small objects in the solar system have moons," Stern says.

"But I think, just on a visceral level, the fact that Pluto has a whole suite of companions will make some people in the public feel better about its status of planethood."

 [ send green star]

This story has been adapted from a news release issued by European Space Agency.

 [ send green star]

Over a billion kilometres away, Saturn's largest moon, Titan, holds tantalising clues to how life began here on Earth.

In the most ambitious and expensive interplanetary space mission of all time, the Cassini-Huygens spacecraft made a seven-year trek across the Solar System to attempt first contact with the Earth-like moon of Titan by landing a probe on its unseen surface.

The first close up images of Saturn and its many moons were taken in the early 1980s by the Voyager One Deep Space Probe. One moon stood out from all the rest, the mysterious moon of Titan. Unlike any moon that had ever been seen, it had a thick almost Earth-like atmosphere. It was also shrouded in a thick orange haze which prevented Voyager from seeing down to the moon's surface. Scientists knew they had to go back.

Launched in 1997, the Cassini-Huygens spacecraft was the result of a unique transatlantic $3.2 billion collaboration between NASA and the European space agencies. Steered from NASA's JPL mission control in Pasadena California, the craft took seven years to reach Saturn. It took a long slingshot route via Venus twice, the Earth and Jupiter to pick up enough speed to reach its final destination.

When it finally arrived in July 2004, the spacecraft had to carry out a very dangerous manoeuvre and pass between Saturn's rings in order to get into orbit around the giant planet. Even the tiniest grain of dust could have ripped through the spacecraft and destroyed the mission.

On Christmas Day 2004, the European-built Huygens probe was finally released from the Cassini mothership, ready to descend to Titan. The probe's trajectory had to be absolutely spot on, as without any engines even a slight misjudgement could not be corrected later and would mean Huygens missing its target altogether.

January 14 2005. The Huygens probe finally reached Titan's upper atmosphere. Mission control had now transferred to ESA in Darmstardt, Germany, but all the scientists could do was sit and wait, as the probe was running on automatic. For any chance of success, the probe's heat shield had to protect the craft from the fierce temperatures of re-entry, and its three parachutes had to deploy correctly in sequence to slow its descent.

Amazingly, long before they expected to hear from Huygens, the probe's faint carrier signal was picked up on Earth by the massive Robert C Byrd radio telescope at Greenbank in West Virginia. Not much stronger than a mobile phone, and travelling over a billion kilometres through space, the signal was too weak to carry any real data, but at least they knew the probe had survived entry and was now under parachute.

Some hours later, the scientific data finally started coming through, relayed via the orbiting Cassini. To their horror, one of the vital data-streams had not been switched on. Fortunately most of the data was coming through on the single channel, but crucially half the images were lost.

After years of waiting, Titan was finally revealed. With Huygens built to sniff and taste the atmosphere on its way down, it discovered it was similar in many ways to that of the Earth in its infancy, four billion years ago. Titan's chemistry is still a long way from what we see as 'living', yet it was found to contain a rich cocktail of organic carbon-based chemicals, thought to be important as the precursors to life.

Now visible beneath the impenetrable orange haze, Titan appears to look a lot like Earth. The images beamed back from over a billion kilometres away show lake beds, river channels, gulleys and canyons. But these river channels are gouged not by water, but by a rain of liquid methane. The surface itself is not made of rock, but of solid ice, and Huygens' landing site was strewn with small round ice pebbles, lying in a bed of icy sand grains. Although home to a somewhat cold alien chemistry, in many respects Titan is driven by exactly the same geological and meteorological processes that shape and contour our own planet. Titan is certainly a place like home.

 [ send green star]

Government policy has consistently been to support robot missions, such as the European Space Agency's Venus Express probe which is due to blast off next week, but not human space exploration.

Helen Sharman became the first Briton in space when she blasted off in the Soviet Soyuz TM-12 capsule on May 18, 1991. Michael Foale, a duel US-British national, has flown missions with NASA.

The report says that human expeditions could help solve profound scientific questions such as the history of the solar system and the existence of life beyond Earth, and would also boost British industry and inspire future achievement among children.

"We find that profound scientific questions relating to the history of the solar system and the existence of life beyond Earth can best -- perhaps only -- be achieved by human exploration on the Moon or Mars, supported by appropriate automated systems," a summary of the report said.

"The wider commercial educational, social and political benefits help justify the substantial expenditure that full UK participation in a future international program of HSE (human space exploration) will require."

Expanding the space programme would require an investment of about Stg.150 million per year, a massive expansion of the current government science budget.

Professor Frank Close, of Oxford University, chaired the commission and wrote the report with former RAS president Professor Ken Pounds, from the University of Leicester, and Dr John Dudeney, Deputy Director of the British Antarctic Survey.

The British government must decide in December whether to support the European Space Agency's Aurora program, which has the long-term goal of sending astronauts to Mars.

privacy       terms      © The Australian

 [ send green star]

Resisting the pull: The gas around black holes can nuture new stars. [File photo] (Reuters)

 [ send green star]

 [ send green star]

Who's a big baby? Composite image of the distant galaxy (Image: NASA/ESA/R Hurt, Spitzer Science Center)

Astronomers using two powerful telescopes say they are surprised to have detected a 'big baby' galaxy, vastly heavy for its young age and its location in the early universe.

Astronomers have long theorised that galaxies form when stars gradually cluster together, with small galaxies preceding bigger galaxies.

But the stars in this cosmic infant, less than a billion years old, have eight times the mass of those in the 13-billion-year-old Milky Way, which contains Earth.

The findings are to be reported in November and December in the Astrophysical Journal.

Researchers using NASA's Hubble and Spitzer space telescopes found the young galaxy.

They looked back in time to a point some 800 million years after the Big Bang explosion that many scientists believe gave birth to the universe.

The discovery of this massive, well-developed galaxy at such an early point in time means astronomers may have to adjust their ideas on when galaxies and other cosmic objects form, says Dr Massimo Stiavelli of the Space Telescope Science Institute, which deals with Hubble's findings.

"It means that the process of galaxy formation started really very early on," Stiavelli says.

"It pushes back things like first light, which is the thing we are all hunting for."

Hubble survey
Before the emergence of the first light source, the universe is thought to have been suffused with a generic glow, caused by microwave background radiation from the Big Bang.

The galaxy, known as HUDF-JD2, was hiding in a tiny patch of sky, about one-tenth the size of the full Moon, known as the Hubble Ultra Deep Field, because the Hubble Space Telescope made a detailed survey there.

Rather than a 2D picture, the Hubble survey is a bit like a core sample of the cosmos, peering narrowly into the vast distance of space, and therefore back in time about 13 billion years.

Even Hubble's cameras could not see this galaxy in visible light; it was only detected in infrared images made by Hubble and an infrared camera at the European Southern Observatory in Chile. In general, older astronomical objects appear redder than younger objects.

The Spitzer telescope, which is sensitive to the light from older, redder stars, found the baby galaxy to be unexpectedly bright in infrared light, suggesting a very massive object, especially for its early era.

"This would be quite a big galaxy even today," says Dr Mark Dickinson of the US National Optical Astronomy Observatory and lead scientist for the Spitzer results.

"At a time when the universe was only 800 million years old, it's positively gigantic."

 [ send green star]

Astronomers have found compelling evidence that a supernova shock wave has produced a large amount of cosmic rays, particles of mysterious origin that constantly bombard the Earth. This discovery, made with NASA's Chandra X-ray Observatory, supports theoretical arguments that shock waves from stellar explosions may be a primary source of cosmic rays.

This finding is important for understanding the origin of cosmic rays, which are atomic nuclei that strike the Earth's atmosphere with very high energies. Scientists believe that some are produced by flares on the Sun, and others by similar events on other stars, or pulsars or black hole accretion disks. But, one of the prime suspects has been supernova shock waves. Now, a team of astronomers has used Chandra observations of Tycho's supernova remnant to strengthen the case for this explanation.

"With only a single object involved we can't state with confidence that supernova shock waves are the primary source of cosmic rays," said John P. Hughes of Rutgers University in Piscataway, New Jersey, and coauthor of a report to be published in an upcoming issue of The Astrophysical Journal. "What we have done is present solid evidence that the shock wave in at least one supernova remnant has accelerated nuclei to cosmic ray energies."

In the year 1572, the Danish astronomer Tycho Brahe observed and studied the sudden appearance of a bright "new star" in the constellation Cassiopeia. Now known as Tycho's supernova remnant, the event created a sensation in Tycho's time because it exploded the myth that stars never change.

Four centuries later, the Chandra results on Tycho's remnant show that some modern ideas of the aftermath of supernova explosions may have to be revised. The report by Hughes and colleagues demonstrates that the shock wave produced by the explosive disruption of the star behaves in a way that cannot be explained by the standard theory.

The supernova debris is observed to expand at a speed of about six million miles per hour. This rapid expansion has created two X-ray emitting shock waves - one moving outward into the interstellar gas, and another moving inward into the stellar debris. These shock waves, analogous to the sonic boom produced by supersonic motion of an airplanes, produce sudden, large changes in pressure, and temperature behind the wave.

According to the standard theory, the outward-moving shock should be about two light-years ahead of the stellar debris (that's half the distance from our sun to the nearest star). What Chandra found instead is that the stellar debris has kept pace with the outer shock and is only about half a light-year behind.

"The most likely explanation for this behavior is that a large fraction of the energy of the outward-moving shock wave is going into the acceleration of atomic nuclei to speeds approaching the speed of light," said Jessica Warren, also of Rutgers University, and the lead author of the report in the Astrophysical Journal.

Previous observations with radio and X-ray telescopes had established that the shock wave in Tycho's remnant was accelerating electrons to high energies. However, since high-speed atomic nuclei produce very weak radio and X-ray emission also, it was not known whether the shock wave was accelerating nuclei as well. The Chandra observations provide the strongest evidence yet that nuclei are indeed accelerated, and that the energy contained in high-speed nuclei is about 100 times that in the electrons.

Hughes also pointed out that the Chandra result for Tycho's remnant significantly changes astronomers' view of the evolution of supernova remnants. A large component of cosmic ray nuclei alters the dynamics of the shock wave, and may require changing the way that astronomers estimate the explosive energy of a supernova from the properties of its remnant.

NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

Additional information and images are available at:

http:/​/​chandra.harvard.edu
and
http:/​/​chandra.nasa.gov

Editor's Note: The original news release can be found here.

 [ send green star]

The Martian surface has undergone dramatic changes in the last few
years with the appearance of new gullies and fresh boulder tracks, new
images released Tuesday show.

The photos, taken by the orbiting Mars Global Surveyor spacecraft,
suggest that the Red Planet is perhaps more active than previously
thought.

The spacecraft, in its ninth year in orbit, spotted two fresh
gullies on a Martian sand dune that were not present in 2002.
Scientists think the gullies might have formed when frozen carbon
dioxide trapped by windblown sand vaporized, releasing gas that allowed
the sand to flow freely.

The spacecraft also took images of boulder tracks at another site
that were not there two years ago. The tracks were probably caused by
dozens of boulders rolling down a slope from strong wind or a quake,
scientists said.

Researchers also noted that impact craters forming since the 1970s
suggest that crater-formation is a slow process, occurring at one-fifth
the pace previously thought.

The pace is important because it is used to estimate the age of
Martian surfaces, said Michael Malin, principal investigator of the
camera aboard the spacecraft.

The planet may be undergoing a climate change, according to images
that show a shrinking of carbon dioxide deposits near the south pole.
For the last three Martian summers, the deposits have shrunk from the
previous year.

The Mars Global Surveyor was launched in 1996 and entered orbit a
year later. The project is managed by NASA's Jet Propulsion Laboratory.

 [ send green star]

Images show contrasting hilly and smooth regions on the asteroid

The Japanese Hayabusa spacecraft has approached within 20km (12 miles) of the asteroid it has been travelling to for more than two years.

The probe will collect a sample from the surface of asteroid Itokawa and return it to Earth for analysis.

Mission scientists hope this will shed light on how these mysterious Solar System bodies formed and evolved.

Hayabusa has been using an efficient ion engine propulsion system to reach its target.

The probe will now hover where it is, gathering data on Itokawa from a distance.

Sample return

The plan is for the probe to land on the asteroid, collect a sample from the surface and return it to Earth. Hayabusa's sample-return canister should parachute back to Earth in the summer of 2007.

A new image taken by the spacecraft's camera on 12 September shows the contrast between hilly regions and a smooth area on the asteroid.

The spacecraft will return a sample of the asteroid to Earth

Scientific observation of the asteroid, including sampling and topographic measurement, will be carried out over two months.

So far, the Moon remains the only extra-terrestrial body from which samples have been gathered from the surface and returned to Earth.

Asteroids are thought to consist of material left over from the formation of the Solar System 4.6 billion years ago. Most of these fragments - sometimes referred to as minor planets - orbit the Sun in a belt between Mars and Jupiter.

Hayabusa was launched on 9 May 2003 from Japan aboard an M-V-5 rocket.

Its asteroid target was named after the late Dr Hideo Itokawa, considered one of the fathers of Japan's space programme.

 [ send green star]

To help prevent a repeat of the 2003 accident when launch debris damaged the shuttle Columbia, causing it to break up on re-entry, NASA has begun illuminating shuttles with tracking radars during launches and ascent to detect and quantify potential hazards. Concerns about possible disruption of onboard electronic guidance and control systems led NASA to request NIST's help in determining how much radar energy can penetrate the orbiter in key locations.

During the launch of Discovery in July, radar was used to track debris during ascent and NASA considered the NIST shielding data vital to the resumption of shuttle flights.

NIST has been conducting research in this area for several years and has developed a portable system that efficiently measures the electromagnetic shielding characteristics of airframes. The systempreviously has been used to evaluate both commercial and military aircraft. NIST engineers visited the Kennedy Space Center in Florida to evaluate the space shuttle Endeavor and the hanger in which the measurements were made.

The NIST system incorporates ultra-wideband antennas, a precision optical link between them, and a computerized data analysis system. The two-step measurement process consisted of a reference measurement with the transmitting and receiving antennas outside the shuttle, and a penetration measurement with the receiving antennas at selected locations inside the orbiter. A computerized comparison of these two measurements over specific time periods and frequency bands provided a measure of shielding characteristics in the frequency range 30 megahertz to 6 gigahertz. The data enabled NASA to set safe power levels on radar systems used to detect debris.

This story has been adapted from a news release issued by National Institute of Standards and Technology.

 [ send green star]

In 1997, Comet Hale-Bopp, which came in towards Earth from beyond Pluto, put on a spectacular show in Italian skies (Image: A Dimai/Col Druscie Obs/AAC)

Destructive comets, like the one many people say slammed into the Tunguska region of Siberia last century, are much rarer than we think, new research finds.

Australian scientist Dr Paul Francis of the Research School of Astronomy and Astrophysics at Mount Stromlo, estimates small comets that pose a risk to Earth are half as common as others predict.

"These things are pretty rare," says Francis, who will report his findings in the Astrophysical Journal.

"I calculate that small comets, capable of destroying a city, only hit the Earth once every 1000 years or so."

But the risk to Earth from larger comets, around 1 kilometre wide, has not changed.

Luckily such continent-busting comets, of the size seen in the movie Deep Impact, are much rarer.

The risk of these large comets posing a risk to Earth is up to one in every 150 million years, depending on where the comets originate.

Listen to the sound of a comet as it swings in from beyond Pluto and sunlight warms it up, causing molecules to vapourise from its surface (Sound: Paul Francis/Australian National University/mp3 file, 663.3kb)
Ridiculous estimates of comets
Francis says previous estimates on comet hazards were based on incorrect extrapolations from the comet reports of amateur astronomers.

In 1967 a US astronomer, Edgar Everhart, calculated that the two comets a year being picked by amateur astronomers represented only 3% of the comets actually out there.

Francis' suspicions about the accuracy of this estimate were roused when he used Everhart's calculations to estimate the number of comets that would be picked up by a new telescope being built at Mount Stromlo.

Francis calculated the SkyMapper telescope would find 10,000 "long-period" comets a year, which he thought "seemed ridiculous".

These long-period comets originate from the Oort Cloud, believed to be a vast cloud of comets orbiting the Sun far beyond Pluto, that are occasionally nudged into an orbit that threatens Earth.

 [ send green star]

The Cassini spacecraft has discovered the long, cracked features dubbed "tiger stripes" on Saturn's icy moon Enceladus are very young -- between 10 and 1,000 years young.

These findings support previous results showing the moon's southern pole is active. The pole had episodes of geologic activity as recently as 10 years ago. These cracked features are approximately 130 kilometers long (80 miles), spaced about 40 kilometers (25 miles) apart and run roughly parallel to one another.

The cracks act like vents. They spew vapor and fine ice water particles that have become ice crystals. This crystallization process can be dated, which helped scientists pin down the age of the features.

"There appears to be a continual supply of fresh, crystalline ice at the tiger stripes, which could have been very recently resurfaced," said Dr. Bonnie Buratti. She is a team member of the Cassini visual and infrared mapping spectrometer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Enceladus is constantly evolving and getting a makeover."

This finding is especially exciting because ground-based observers have seen tiny Enceladus brighten as its south pole was visible from Earth. Cassini allows scientists to see close up that the brightening is caused by geologic activity. When NASA's Voyager 2 spacecraft flew over the moon's north pole in 1981, it did not observe the tiger stripes.

Cassini's visual and infrared mapping spectrometer shows water ice exists in two forms on Enceladus: in pristine, crystalline ice and radiation-damaged amorphous ice.

When ice comes out of the "hot" cracks, or "tiger stripes," at the south pole, it forms as fresh, crystalline ice. As the ice near the poles remains cold and undisturbed, it ages and converts to amorphous ice. Since this process is believed to take place over decades or less, the tiger stripes must be very young.

"One of the most fascinating aspects of Enceladus is that it is so very small as icy moons go, but so very geophysically active. It's hard for a body as small as Enceladus to hold onto the heat necessary to drive such large-scale geophysical phenomena, but it has done just that," said Dr. Bob Brown. Brown is a team leader for the visual and infrared mapping spectrometer at the University of Arizona, Tucson. "Enceladus and its incredible geology is a marvelous puzzle for us to figure out."

Adding to the already mounting evidence for an active body is the correlation of results from multiple instruments. Cassini's cameras provided detailed images of the south polar cap, in which the tiger stripe fractures were found to be among the hottest features.

The timing of the craft's ion and neutral mass spectrometer and the cosmic dust analyzer observations seems to indicate the vapor and fine material are originating from the "hot" polar cap region. These data also indicate the production of water vapor and ejection of fine material are connected, as they are in a comet. This suggests that vapor and dust-sized icy material are coming from the tiger stripes.

Enceladus is on a short list of bodies in our solar system where scientists have found internal activity. The others are the volcanoes on Jupiter's moon Io and geysers on Neptune's moon Triton.

Data for these measurements were taken during Cassini's closest flyby on July 14, 2005. The spacecraft came within 175 kilometers (109 miles) of the surface of Enceladus. Enceladus is 500 kilometers (314 miles) across and has the most reflective surface in the solar system.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington.

 [ send green star]

Apophis, a 1,059-foot-wide asteroid, has excited astronomers since it was spotted last year. After observing it for a while, scientists concluded that it has only a 1-in-8,000 chance of ever smacking into Earth. But even that slim chance has them talking and NASA pondering how to keep track of it — just in case.

"The most likely turn of events is that it will miss us," says Steve Chesley of NASA's Jet Propulsion Laboratory in Pasadena, Calif., which has monitored the asteroid since December as part of its normal watch over "near-Earth" asteroids. "We are prepared for the worst but certainly don't want to act too hastily."

In June, former astronaut Russell Schweickart petitioned NASA chief Michael Griffin to consider placing a transmitter on Apophis, which is named after an ancient Egyptian god of darkness and destruction, by 2013. Chesley says NASA will respond in a few weeks.

The key question about Apophis is whether its 2029 trajectory will go through a roughly 2,000-foot-wide region called a "keyhole," says astronomer Clark Chapman of Southwest Research Institute in Boulder, Colo. If it passes through that region — that one-in-8,000 chance — its course would be deflected to make an impact with Earth in 2036 very likely, he says.

This asteroid passes near Earth every seven or eight years, but the 2029 trajectory is expected to be its closest approach. In the petition, Schweickart warned that waiting for better estimates of Apophis' likely path in 2020, after another flyby of Earth, would leave little time to deflect the asteroid away from the keyhole.

If the asteroid were to strike Earth, scientists say the impact would be felt somewhere on a line stretching from Japan to the Caribbean. It would create a roughly 2-mile-wide crater and possibly create a tsunami.

But Chesley says directing the asteroid away from Earth might take only a blast the size of NASA's "Deep Impact" mission, which smacked a probe into the comet called Tempel 1 in July. A 2029 deflection mission would be easier because an asteroid practically saunters compared with the speed of a comet, and this one passes within 22,600 miles of Earth's center -"extraordinarily close for an object of this size," he says.

The asteroid should be visible, about as bright as the stars in the Big Dipper constellation, to observers in Europe, Chapman says. Such a close asteroid flyby comes only once every 1,500 years. "Certainly this is a profound scientific opportunity," Chesley adds.

Astronomers already are pondering what the 2029 encounter will do to the asteroid. The Earth's gravity will exert strong tidal forces on Apophis, which could change the asteroid's shape if it is only a loose agglomeration of rock. The flyby also will permanently alter the asteroid's orbit, although how is still uncertain.

Radar observations next spring should improve estimates of the asteroid's path and might indicate a lower impact risk.

"But there are more asteroids out there, so we should be paying attention," Chapman says.

 [ send green star]

Mission operators at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md, said MESSENGER's systems performed flawlessly. The spacecraft swooped around Earth, coming to a closest approach point of approximately 1,458 miles (2,347 kilometers) over central Mongolia at 3:13 p.m. EDT on August 2.

The spacecraft used the tug of Earth's gravity to significantly change its trajectory. Its average orbit distance is nearly 18 million miles closer to the sun. The maneuver sent it toward Venus for another gravity-assist flyby next year.

Launched Aug. 3, 2004, from Cape Canaveral Air Force Station, Fla., the solar-powered spacecraft is approximately 581 million miles (930 million kilometers) into a 4.9 billion mile (7.9 billion kilometer) voyage that includes 14 more loops around the sun. MESSENGER will fly past Venus twice and Mercury three times before moving into orbit.

The Venus flybys in October 2006 and June 2007 will use the planet's gravity to guide MESSENGER toward Mercury's orbit. The Mercury flybys in January 2008, October 2008 and September 2009 will help MESSENGER match the planet's speed. These events will set up the maneuver in March 2011 that starts a year-long science orbit around Mercury.

"This Earth flyby is the first of a number of critical mission milestones during MESSENGER's circuitous journey toward Mercury orbit insertion," said Sean C. Solomon, the mission's principal investigator from the Carnegie Institution of Washington. "Not only did it help the spacecraft sharpen its aim toward our next maneuver, it presented a special opportunity to calibrate several of our science instruments."

MESSENGER's main camera snapped several approach shots of Earth and the moon during the past week. Today the camera is taking a series of color images, beginning with South America and continuing for one full Earth rotation. Science team members will string the images into a video documenting MESSENGER's departure.

On Earth approach, the craft's atmospheric and surface composition spectrometer made several scans of the moon in conjunction with the camera observations. In addition, the particle and magnetic field instruments spent several hours measuring Earth's magnetosphere. The science team will download the data and images through NASA's Deep Space Network over the next several weeks, continuing assessment of the instruments' performance.

MESSENGER will conduct the first orbital study of Mercury, the least explored of the terrestrial planets that include Venus, Earth and Mars. During one Earth year (four Mercury years), MESSENGER will provide the first images of the entire planet. It will collect detailed information about the composition and structure of Mercury's crust, its geologic history, nature of its atmosphere and magnetosphere, makeup of its core and polar materials.

MESSENGER, short for MErcury Surface, Space ENvironment, GEochemistry, and Ranging, is the seventh mission in NASA's Discovery Program of lower-cost scientifically focused exploration projects. APL designed, built and operates the spacecraft and manages the mission for NASA's Science Mission Directorate.

This story has been adapted from a news release issued by National Aeronautics And Space Administration.

 [ send green star]

Scientists funded by NASA have made big strides in learning how to forecast "all clear" periods, when severe space weather is unlikely. The forecasts are important because radiation from particles from the sun associated with large solar flares can be hazardous to unprotected astronauts, airplane occupants and satellites.

"We have a much better insight into what causes the strongest, most dangerous solar flares, and how to develop forecasts that can predict an 'all clear' for significant space weather, for longer periods," said Dr. Karel Schrijver of the Lockheed Martin Advanced Technology Center (ATC), Palo Alto, Calif. He is lead author of a paper about the research published in the Astrophysical Journal.

Solar flares are violent explosions in the atmosphere of the sun caused by the sudden release of magnetic energy. Like a rubber band twisted too tightly, stressed magnetic fields in the sun’s atmosphere (corona) can suddenly snap to a new shape. They can release as much energy as one, 10 billion megaton nuclear bomb.

Predicting space weather is a complicated problem. Solar forecasters focus principally on the complexity of solar magnetic field patterns to predict solar storms. This method is not always reliable, because solar storms require additional ingredients to occur. It has long been known large electrical currents must be present to power flares.

Insight into the causes of the largest solar flares came in two steps. "First, we discovered characteristic patterns of magnetic field evolution associated with strong electrical currents in the solar atmosphere," said ATC's Dr. Marc DeRosa, co-author of the paper. "It is these strong electrical currents that drive solar flares."

Subsequently, the authors discovered the regions most likely to flare had new magnetic fields merge into them that were clearly out of alignment with the existing field. This emerging field from the solar interior appears to induce even more current as it interacts with the existing field.

The team also found flares do not necessarily occur immediately upon the emergence of a new magnetic field. Apparently the electrical currents must build up over several hours before the fireworks start. Predicting exactly when a flare will happen is like studying avalanches. They occur only after enough snow built up. Once the threshold is reached, the avalanche can happen anytime by processes not yet completely understood.

"We found the current-carrying regions flare two to three times more often than the regions without large currents," Schrijver said. "Also, the average flare magnitude is three times greater for the group of active regions with large current systems than for the other group."

The researchers made the discovery by comparing data about magnetic fields on the sun’s surface to the sharpest extreme-ultraviolet images of the solar corona. The magnetic maps were from the Michelson Doppler Imager (MDI) instrument on board Solar and Heliospheric Observatory (SOHO) spacecraft. SOHO is operated under a cooperative mission between the European Space Agency and NASA.

The corona images were from the NASA Transition Region and Coronal Explorer spacecraft (TRACE). The team also used computer models of a three-dimensional solar magnetic field without electrical currents based on SOHO images. Differences between images and models indicated the presence of large electrical currents.

"This is a result that is more than the sum of two individual missions," said Dr. Dick Fisher, Director of NASA's Sun-Solar System Connection Division. "It's not only interesting scientifically, but has broad implications for society."

For imagery about the research on the Web, visit:

http:/​/​www.nasa.gov/​vision/​universe/​solarsystem/​clear_weather.html For information about NASA and agency programs on the Web, visit:

http:/​/​www.nasa.gov/​home/​index.html

 [ send green star]

NASA is targeting March for the next Space Shuttle mission (STS-121). The mission will be the second test flight to the International Space Station in the Shuttle Return to Flight sequence.

NASA Administrator Michael Griffin and Associate Administrator for Space Operations Bill Gerstenmaier made the announcement today at a news conference at the agency's headquarters in Washington.

"We are giving ourselves what we hope is plenty of time to evaluate where we are," said Administrator Griffin. "We don't see the tasks remaining before us being as difficult as the path behind us."

Based on NASA's self-imposed optimum lighting requirements, the earliest possible launch opportunity for the STS-121 mission is March 4, 2006. The Space Shuttle Discovery will be used for the mission, instead of Space Shuttle Atlantis.

Moving toward a no earlier than March launch for STS-121 will allow engineering teams more time to properly evaluate the issue of large pieces of insulating foam that came off Discovery's external fuel tank during launch last month.

Targeting March also allows the Space Shuttle Program to put itself into a better posture for future Shuttle missions to the Space Station. Changing Orbiters for the STS-121 mission enables use of Atlantis for the following mission, STS-115, which will resume assembly of the Station.

The switch frees Atlantis to fly the remaining Space Station truss segments, which are too heavy for Discovery, in 2006. By changing the Orbiter line up, the Shuttle program will not have to do two back-to-back missions with Atlantis, as previously scheduled.

"It really makes sense to move to the March timeframe," Gerstenmaier said. "We're looking at the Shuttle missions to support the most robust flight sequence for the Space Station and to make the whole sequence flow better. This extra time helps us make sure that all the work we need to do fits and that there are no other issues."

Discovery's recent mission, STS-114, and the STS-121 mission are test flights. They will enable NASA to evaluate new safety procedures and equipment, giving the agency greater confidence that the Shuttle can be flown safely through its planned retirement date of 2010.

The external fuel tanks at NASA's Kennedy Space Center in Florida will be shipped back to the Michoud Assembly Facility in Louisiana for tests and potential modifications.

For information about the STS-114 Return to Flight mission and future Shuttle flights, visit:

http:/​/​www.nasa.gov/​returntoflight For information about NASA and agency programs on the Web, visit:

http:/​/​www.nasa.gov/​home/​index.html

 [ send green star]

Peter Thomas, a senior research associate in astronomy at Cornell University and lead author on the paper, and Mark Robinson, research associate professor of geological sciences at Northwestern University, analyzed images of Eros gathered four years ago by the Near Earth Asteroid Rendezvous mission. The mission mapped the 20-mile-long, potato-shaped asteroid and its thousands of craters in detail. The two researchers focused on a large impact crater, known as the Shoemaker crater, and a few unusual crater-free areas.

In the Nature article, Thomas and Robinson show that the asteroid's smooth patches can be explained by a seismic disturbance that occurred when a meteoroid crashed into Eros, shaking the asteroid and creating Shoemaker crater. The shaking caused loose surface material to fill some small craters, essentially erasing craters from approximately 40 percent of Eros' surface and making the asteroid appear younger than its actual age.

The fact that seismic waves were carried through the center of the asteroid after the impact shows that the asteroid's interior is cohesive enough to transmit such waves, say the authors. And the smoothing-out effect within a radius of up to 5.6 miles from the 4.7-mile Shoemaker crater -- even on the opposite side of the asteroid -- indicates that Eros' surface is loose enough to get shaken down by the impact.

Asteroids are small, planet-like bodies that date back to the beginning of the solar system, so studying them can give astronomers insight into the solar system's formation. And while no asteroids currently threaten Earth, knowing more about their composition could help prepare for a possible future encounter. Eros is the most carefully studied asteroid, in part because its orbit brings it close to earth.

Thomas and Robinson considered various theories for the regions of smoothness, including the idea that ejecta from another impact had blanketed the areas. But they rejected the ejecta hypothesis when calculations showed an impact Shoemaker's size wouldn't create enough material to cover the surface indicated. And even if it did, they add, the asteroid's irregular shape and motion would cause the ejecta to be distributed differently. In contrast, the shaking-down hypothesis fits the evidence neatly.

 [ send green star]

University of California, Berkeley, assistant research astronomer Franck Marchis and his colleagues at the Observatoire de Paris have discovered the first triple asteroid system - two small asteroids orbiting a larger one known since 1866 as 87 Sylvia.

Because 87 Sylvia was named after Rhea Sylvia, the mythical mother of the founders of Rome, Marchis proposed naming the twin moons after those founders: Romulus and Remus. The International Astronomical Union (IAU) approved the names, to be announced in its Aug. 11 circular.

Marchis and his colleagues will report their discovery in the Aug. 11 issue of the journal Nature simultaneously with an announcement that day at theAsteroid Comet Meteor conference in Armação dos Búzios, in the Brazilian state of Rio de Janeiro.

The asteroid 87 Sylvia is one of the largest known from the asteroid main belt, which is located between the orbits of Mars and Jupiter. Shaped like a lumpy potato, Sylvia is about 280 kilometers (175 miles) in diameter and is located in the Cybele outer part of the belt, about 3.5 astronomical units (AU) from the sun. An AU is 93 million miles, the average distance between the sun and Earth.

Four years ago, Sylvia was discovered to have a moon, making it one of some 60 known binary asteroids in various asteroid populations of the solar system. Seventeen of these binary systems are in the main asteroid belt and have been imaged directly either by adaptive optics systems on large, ground-based telescopes or by the Hubble Space Telescope.

Now, a second moon has been seen around Sylvia, making it a triple asteroid system. Sylvia's newly discovered moons orbit in nearly circular orbits in the same plane and direction (prograde) as the moon orbits the Earth. The closest moonlet, orbiting about 710 km (450 miles) from Sylvia, is Remus, a body only 7 km (4.4 miles) across and circling Sylvia every 33 hours. The second, Romulus, orbits at about 1360 km (860 miles), measures about 18 km (11.3 miles) across, and orbits in 87.6 hours. The asteroid Sylvia spins at a rapid rate, once every 5 hours and 11 minutes.

"People have been looking for multiple asteroid systems for a long time, because binary asteroid systems in the main belt seem to be common and formation scenarios, such as a collision between two asteroids followed by disruption and re-accretion, suggest that fragments should be orbiting bigger asteroids," Marchis said. "I couldn't believe we found one."

From two months' of observations of the moonlets' orbits, Marchis and his Paris colleagues were able to precisely calculate the mass and density of Sylvia, which shows it to be a "rubble-pile" asteroid, Marchis said. These asteroids are loose aggregations of rock presumably created when one asteroid smacked into another, disrupting one or both of them. A new asteroid formed later by accretion of large fragments from the disruption. The moonlets probably are debris left over from the collision that were gravitationally captured by the newly formed asteroid and which eventually settled into orbits around it.

"That's why most main-belt asteroids with companions have a rubble-pile structure," he said. "Because of the scenarios of their formation, we expect to see more multiple asteroid systems like this."

The density, 1.2 grams per cubic centimeter, is 20 percent higher than the density of water, which suggests it is composed of water, ice and rubble from a primordial asteroid, probably a hydrated carbonaceous chondrite, based on previous spectroscopic studies of the asteroid.

"It could be up to 60 percent empty space," said astronomer Daniel Hestroffer, one of three coauthors from the Institut de Mécanique Céleste et Calculs d'Éphémérides at the Observatoire de Paris.

The discovery was made with one of the European Southern Observatory's 8-meter telescopes (Yepun) of the Very Large Telescope at Cerro Paranal, using the telescope's infrared camera and the high angular resolution provided by the adaptive optics system (NACO). Via the observatory's promising "service observing mode," Marchis and his colleagues were able to obtain sky images of many asteroids over a six-month period without actually having to travel to Chile. DVD data of the observations were sent regularly via mail to Berkeley.

Marchis had the discovery sitting on his shelf for months, since November 2004, because he waited for the completion of the project before starting to process the data and before sending them to colleague Pascal Descamps of the Observatoire de Paris. Just as Marchis was set to go on vacation in March 2005, Descamps sent him a brief note entitled "87 Sylvia est triple?" pointing out that he could see two moonlets around several images of Sylvia. The entire team then focused quickly on analysis of the data, wrote a paper, submitted an abstract to the August meeting in Rio de Janeiro and submitted a naming proposal to the IAU.

Marchis and his colleagues hope to use the adaptive optics of the Keck and the Gemini telescopes to obtain better images of the triple-asteroid system in order to pin down the precise orbits, verify Sylvia's formation scenario and chart the system's evolution. Already they see precession of the moon's orbits resulting from the irregular shape of Sylvia.

This story has been adapted from a news release issued by University of California - Berkeley.

 [ send green star]

New images, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft, show a patch of water ice sitting on the floor of an unnamed crater near the Martian north pole.

 [ send green star]

A radical new theory of time and motion has some of the world's physicists doubting the claim while others laud the 27-year-old college dropout who came up with it, an unknown big thinker named Peter Lynds.

Lynds says he's no Einstein. In fact, he is not a fully trained theorist. He has no real academic credentials. But he does appear to have a new career, now that one other theorist compared his work to the groundbreaking ideas of Albert Einstein.

In a paper published in the August issue of Foundations of Physics Letters, Lynds claims to see time and motion with unprecedented theoretical clarity.

Lynds refutes an assumption dating back 2,500 years, that time can be thought of in physical, definable quantities. In essence, scientists have long assumed that motion can be considered in frozen moments, or instants, even as time flows on.

In an e-mail interview from New Zealand, Lynds told SPACE.com how he sees the physical world:

"There isn't a precise instant underlying an object's motion," he said. "And as its position is constantly changing over time -- and as such, never determined -- it also doesn't have a determined position at any time."

Nor does time flow, Lynds says. More on that later.

Importantly, Lynds claims his theory solves Zeno's paradoxes, which have frustrated creative brains for millennia.

The most famous paradox invented by Zeno, the Greek philosopher, is called "Achilles and the tortoise." A tortoise gets a 10-meter head start in a race against Achilles. Zeno says the tortoise can never be passed. His logic: When Achilles has run 10 meters, the tortoise will have moved a meter; Achilles goes another meter, and the tortoise crawls 10 more centimeters. The race continues in this ever-more boring and incremental fashion.

A related paradox, called the dichotomy, argues that you can never reach a goal. First you'll have to travel half the distance, then half that distance, and so on. You might as well stay home.

Reality is different, of course -- goals are reached and tortoises often lose. But philosophers and physicists have not been able to explain the paradoxes away.

Lynds claims the paradoxes result from an incorrect physical assumption from long ago. From ancient times to the present, philosophers and physicists have assumed that objects in motion have determined positions at any instant in time. It's not true, Lynds says.

 [ send green star]

NASA's Chandra X-ray Observatory survey of nearby sun-like stars suggests there is nearly three times more neon in the sun and local universe than previously believed. If true, this would solve a critical problem with understanding how the sun works.
Illustration and spectra of neon abundance in a star. (Image courtesy of Chandra X-ray Center)

"We use the sun to test how well we understand stars and, to some extent, the rest of the universe," said Jeremy Drake of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "But in order to understand the sun, we need to know exactly what it is made of," he added.

It is not well known how much neon the sun contains. This is critical information for creating theoretical models of the sun. Neon atoms, along with carbon, oxygen and nitrogen, play an important role in how quickly energy flows from nuclear reactions in the sun's core to its edge, where it then radiates into space.

The rate of this energy flow determines the location and size of a crucial stellar region called the convection zone. The zone extends from near the sun's surface inward approximately 125,000 miles. The zone is where the gas undergoes a rolling, convective motion much like the unstable air in a thunderstorm.

"This turbulent gas has an extremely important job, because nearly all of the energy emitted at the surface of the sun is transported there by convection," Drake said.

The accepted amount of neon in the sun has led to a paradox. The predicted location and size of the solar convection zone disagree with those deduced from solar oscillations. Solar oscillations is a technique astronomers previously relied on to probe the sun's interior. Several scientists have noted the problem could be fixed if the abundance of neon is in fact about three times larger than currently accepted.

Attempts to measure the precise amount of neon in the Sun have been frustrated by a quirk of nature; neon atoms in the Sun give off no signatures in visible light. However, in a gas heated to millions of degrees, neon shines brightly in X-rays. Stars like the sun are covered in this super-heated gas that is betrayed by the white corona around them during solar eclipses. However, observations of the sun's corona are very difficult to analyze.

To probe the neon content, Drake and his colleague Paola Testa of the Massachusetts Institute of Technology in Cambridge, Mass., observed 21 sun-like stars within a distance of 400 light years from Earth. These local stars and the sun should contain about the same amount of neon when compared to oxygen.

However, these close stellar kin were found to contain on average almost three times more neon than is believed for the sun. "Either the sun is a freak in its stellar neighborhood, or it contains a lot more neon than we think," Testa said.

These Chandra results reassured astronomers the detailed physical theory behind the solar model is secure. Scientists use the model of the sun as a basis for understanding the structure and evolution of other stars, as well as many other areas of astrophysics.

"If the higher neon abundance measured by Drake and Testa is right, then it is a simultaneous triumph for Chandra and for the theory of how stars shine," said John Bahcall of the Institute for Advanced Study, Princeton, N.J. Bahcall is an expert in the field who was not involved in the Chandra study. Drake is lead author of the study published in this week's issue of the journal Nature.

NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.
This story has been adapted from a news release issued by Chandra X-ray Center.

 [ send green star]

NASA's next mission to Mars will examine the red planet in unprecedented detail from low orbit and provide more data about the intriguing planet than all previous missions combined. The Mars Reconnaissance Orbiter and its launch vehicle are nearing final stages of preparation at NASA's Kennedy Space Center, Fla., for a launch opportunity that begins Aug. 10.Artist's concept of Mars Reconnaissance Orbiter. (Image courtesy of NASA/Jet Propulsion Laboratory)

The spacecraft will examine Martian features ranging from the top of the atmosphere to underground layering. Researchers will use it to study the history and distribution of Martian water. It will also support future Mars missions by characterizing landing sites and providing a high-data-rate communications relay.

"Mars Reconnaissance Orbiter is the next step in our ambitious exploration of Mars," said NASA's director, Mars Exploration Program, Science Mission Directorate, Douglas McCuistion. "We expect to use this spacecraft's eyes in the sky in coming years as our primary tools to identify and evaluate the best places for future missions to land."

The spacecraft carries six instruments for probing the atmosphere, surface and subsurface to characterize the planet and how it changed over time. One of the science payload's three cameras will be the largest-diameter telescopic camera ever sent to another planet. It will reveal rocks and layers as small as the width of an office desk. Another camera will expand the present area of high-resolution coverage by a factor of 10. A third will provide global maps of Martian weather.

The other three instruments are a spectrometer for identifying water-related minerals in patches as small as a baseball infield; a ground-penetrating radar, supplied by the Italian Space Agency, to peer beneath the surface for layers or rock, ice and, if present, water; and a radiometer to monitor atmospheric dust, water vapor and temperature.

Two additional scientific investigations will analyze the motion of the spacecraft in orbit to study the structure of the upper atmosphere and the Martian gravity field.

"We will keep pursuing a follow-the-water strategy with Mars Reconnaissance Orbiter," said Dr. Michael Meyer, Mars exploration chief scientist at NASA Headquarters. "Dramatic discoveries by Mars Global Surveyor, Mars Odyssey and the Mars Exploration Rovers about recent gullies, near-surface permafrost and ancient surface water have given us a new Mars in the past few years. Learning more about what has happened to the water will focus searches for possible Martian life, past or present."

Dr. Richard Zurek of NASA's Jet Propulsion Laboratory, Pasadena, Calif., project scientist for the orbiter, said, "Higher resolution is a major driver for this mission. Every time we look with increased resolution, Mars has said, 'Here's something you didn't expect. You don't understand me yet.' We're sure to find surprises."

The orbiter will reach Mars in March 2006. It will gradually adjust the shape of its orbit by aerobraking, a technique that uses the friction of careful dips into the planet's upper atmosphere. For the mission's 25-month primary science phase, beginning in November 2006, the planned orbit averages about 190 miles above the surface, more than 20 percent lower than the average for any of the three current Mars orbiters. The lower orbit adds to the ability to see Mars as it has never been seen before.

To get information from its instruments to Earth, the orbiter carries the biggest antenna ever sent to Mars and a transmitter powered by large solar panels. "It can send 10 times as much data per minute as any previous Mars spacecraft," said JPL's James Graf, project manager. "This increased return multiplies the value of the instruments by permitting increased coverage of the surface at higher resolution than ever before. The same telecommunications gear will be used to relay critical science data to Earth from landers."

To loft so big a spacecraft, weighing more than two tons fully fueled, NASA will use a powerful Atlas V launch vehicle for the first time on an interplanetary mission.

The mission is managed by JPL, a division of the California Institute of Technology, Pasadena, for the NASA Science Mission Directorate. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft.

This story has been adapted from a news release issued by NASA/Jet Propulsion Laboratory.

 [ send green star]

Shuttle may launch despite glitch

The Discovery shuttle could lift off on Tuesday even if the sensor problem that prevented the launch on 13 July recurs.

Engineers have raced to isolate the glitch, and have come up with two likely candidates.

The current launch window is open until 31 July, but may be widened into the first week of August.

Discovery's 12-mission to the International Space Station marks Nasa's first shuttle launch since the loss of Columbia on 1 February 2003.

"We have literally run every check that we can think of," said Wayne Hale, shuttle deputy programme manager, "and so far, no repeat."

Wiring switch

Dr Mike Griffin, the US space agency's administrator, said he hoped the problem would recur during countdown tests, so engineers could resolve the problem once and for all.

"What you want of Nasa is that we make the right technical decisions, that we do the right thing, to the extent that we can figure that out, which is hard," he explained.

"We can't restrict the range of our options to those things that are going to present well."

The launch attempt on 13 July was scrubbed when one of four identical engine cut-off (Eco) sensors failed a routine countdown check. The sensors act as fuel gauges, monitoring the volume of cryogenic hydrogen in the shuttle's external tank.

For Tuesday, the wiring between sensors number two - which played up last time - and number four has now been switched, to try to isolate the glitch.

If engineers see a failure in either of these sensors, managers say they will understand the problem well enough to fly Discovery.

However, if an unforeseen problem with the other sensors arises, they will have to abort the launch.

A 'huge effort'

Engineers have so far identified and fixed three electrical grounding issues in the sensor wiring system and also suspect electromagnetic interference from other hardware could be the root cause of the problem.

Mr Hale brandished an example of the sensor involved at a news conference here at Kennedy Space Center.

"Just because I brought this, I don't want anyone to go away with the idea we're indicting the sensors," he told journalists.

Though engineers have completed a battery of "ambient" tests on the sensor system, they have to wait until the early hours of Tuesday to check how they perform with a full tank of cryogenic liquid hydrogen.

Mr Hale countered suggestions that Nasa carry out a "tanking" test, in which the external tank is filled up with cryogenic propellants, before attempting launch.

"I think we're all still struggling a bit with the ghosts of Columbia, so we want to make sure we do this right," said Mr Hale.

"Are we taking care enough to do it right? Based on the last 10 days' worth of effort, the huge number of people and the tremendous number of hours that have been spent testing and analysing - I think we're coming to the right place."

At the right time

The sensors at the heart of Nasa's troubleshooting operation ensure the orbiter's three main engines shut down before its fuel runs out, avoiding the potentially catastrophic scenario of the motors running with empty tanks.

But the agency also needs to be sure that the sensor glitch does not lead to the alternative and equally unwelcome scenario in which the engines shut down too early because the system believes wrongly all the tanks are empty.

An engine shutdown before Discovery reached its intended orbit could force the crew to abort the mission and make an emergency landing.

The US space agency has set Tuesday's launch for 1039 EDT (1439 GMT; 1539 BST).

Discovery's 12-day mission will deliver parts and supplies to the ISS. It will also give the astronauts a chance to test new safety features on the shuttle brought in following the loss of Columbia.

If Tuesday's launch goes ahead as planned, the shuttle will return to Earth on the morning of 7 August, landing at Kennedy Space Center.

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/4714063.stm

Published: 2005/07/25 09:27:39 GMT

© BBC MMV

 [ send green star]

Here come the X-rays, on cue. Scientists studying the Deep Impact collision using NASA's Swift satellite report that comet Tempel 1 is getting brighter and brighter in X-ray light with each passing day.

The X-rays provide a direct measurement of how much material was kicked up in the impact. This is because the X-rays are created by the newly liberated material lifted into the comet's thin atmosphere and illuminated by the high-energy solar wind from the Sun. The more material liberated, the more X-rays are produced.

Swift data of the water evaporation on comet Tempel 1 also may provide new insights into how solar wind can strip water from planets such as Mars.

"Prior to its rendezvous with the Deep Impact probe, the comet was a rather dim X-ray source," said Dr. Paul O'Brien of the Swift team at the University of Leicester. "How things change when you ram a comet with a copper probe traveling over 20,000 miles per hour. Most of the X-ray light we detect now is generated by debris created by the collision. We can get a solid measurement of the amount of material released."

"It takes several days after an impact for surface and sub-surface material to reach the comet's upper atmosphere, or coma," said Dr. Dick Willingale, also of the University of Leicester. "We expect the X-ray production to peak this weekend. Then we will be able to assess how much comet material was released from the impact."

Based on preliminary X-ray analysis, O'Brien estimates that several tens of thousands of tons of material were released, enough to bury Penn State's football field under 30 feet of comet dust. Observations and analysis are ongoing at the Swift Mission Operations Center at Penn State University as well as in Italy and the United Kingdom.

Swift is providing the only simultaneous multi-wavelength observation of this rare event, with a suite of instruments capable of detecting visible light, ultraviolet light, X-rays, and gamma rays. Different wavelengths reveal different secrets about the comet.

The Swift team hopes to compare the satellite's ultraviolet data, collected hours after the collision, with the X-ray data. The ultraviolet light was created by material entering into the lower region of the comet's atmosphere; the X-rays come from the upper regions. Swift is a nearly ideal observatory for making these comet studies, as it combines both a rapidly responsive scheduling system with both X-ray and optical/UV instruments in the same satellite.

"For the first time, we can see how material liberated from a comet's surface migrates to the upper reaches of its atmosphere," said Prof. John Nousek, Director of Mission Operations at Penn State. "This will provide fascinating information about a comet's atmosphere and how it interacts with the solar wind. This is all virgin territory."

Nousek said Deep Impact's collision with comet Tempel 1 is like a controlled laboratory experiment of the type of slow evaporation process from solar wind that took place on Mars. The Earth has a magnetic field that shields us from solar wind, a particle wind composed mostly of protons and electrons moving at nearly light speed. Mars lost its magnetic field billions of years ago, and the solar wind stripped the planet of water.

Comets, like Mars and Venus, have no magnetic fields. Comets become visible largely because ice is evaporated from their surface with each close passage around the Sun. Water is dissociated into its component atoms by the bright sunlight and swept away by the fast-moving and energetic solar wind. Scientists hope to learn about this evaporation process on Tempel 1 now occurring quickly -- over the course of a few weeks instead of a billion years -- as the result of a planned, human intervention.

Swift's "day job" is detecting distant, natural explosions called gamma-ray bursts and creating a map of X-ray sources in the universe. Swift's extraordinary speed and agility enable scientists to follow Tempel 1 day by day to see the full effect from the Deep Impact collision.

For the latest news on Swift analysis of comet Tempel 1, refer to:
http://www.science.psu.edu/alert/Swift-Deep-Impact.htm
http://swift.gsfc.nasa.gov
and
http://swift.sonoma.edu/

The Deep Impact mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, California. Swift is a medium-class NASA explorer mission in partnership with the Italian Space Agency and the Particle Physics and Astronomy Research Council in the United Kingdom, and is managed by NASA Goddard. Penn State controls science and flight operations from the Mission Operations Center in University Park, Pennsylvania. The spacecraft was built in collaboration with national laboratories, universities and international partners, including Penn State University; Los Alamos National Laboratory, New Mexico; Sonoma State University, Rohnert Park, Calif.; Mullard Space Science Laboratory in Dorking, Surrey, England; the University of Leicester, England; Brera Observatory in Milan; and ASI Science Data Center in Frascati, Italy.

This story has been adapted from a news release issued by Penn State.

 [ send green star]

NASA has cleared the Space Shuttle to Return to Flight. After a two-day Flight Readiness Review meeting at NASA's Kennedy Space Center in Florida, senior managers approved a July 13 launch date for Discovery.

Commander Eileen Collins and her crew are scheduled to lift off at 3:51 p.m. EDT on the first U.S. space flight since the February 2003 loss of the Shuttle Columbia.

"After a vigorous, healthy discussion our team has come to a decision: we're ready to go," NASA Administrator Michael Griffin said after the meeting. "The past two and half years have resulted in significant improvements that have greatly reduced the risk of flying the Shuttle. But we should never lose sight of the fact that space flight is risky.

"The Discovery mission, designated STS-114, is a test flight," Griffin said, noting that astronauts will try out a host of new Space Shuttle safety enhancements. In addition, Discovery will carry 15 tons of supplies and replacement hardware to the International Space Station. July 13 is the beginning of three weeks of possible launch days that run through July 31.

NASA's Associate Administrator for Space Operations, William Readdy, chaired the Flight Readiness Review, the meeting that traditionally sets launch dates and assesses the Shuttle's fitness to fly.

"Today's decision is an important milestone in returning the Shuttle to service for the country. Our technical and engineering teams are continuing their in-depth preparations to ensure that Eileen and her crew have a successful mission," he said.

This story has been adapted from a news release issued by NASA/Kennedy Space Center.

 [ send green star]

New images, taken by the High Resolution Stereo Camera (HRSC) aboard ESA’s Mars Express spacecraft, show a large depression called Iani Chaos and the upper reaches of a large outflow channel called Ares Vallis.

Image strips were taken during three orbits from an altitude of 350 km, with a resolution of 15 metres per pixel. The strips have then been matched to a mosaic that covers an area from 342.5º East to 3º North. The Iani Chaos depression – 180 km long and 200 km wide – is connected to the beginning of Ares Vallis by a 100-km wide transition zone.

From here, Ares Vallis continues its course for about 1400 km through the ancient Xanthe Terra highlands, bordered by valley flanks up to 2000 metres high. Eventually Ares Vallis empties into Chryse Planitia.

These images help illuminate the complex geological history of Mars. Ares Vallis is one of several big outflow channels on Mars in this region that formed thousands of millions of years ago. Many surface features suggest that erosion of large water flows had carved Ares Vallis in the Martian landscape.

Most likely gigantic floods ran downhill, carving a deep canyon into Xanthe Terra. Rocks eroded from the valley flanks were milled into smaller fractions and transported in the running water.

Finally this sedimentary load was deposited far north at the mouth of Ares Vallis in the Chryse plains, where NASA’s Mars Pathfinder landed in 1997 to search for traces of water with its small Sojourner rover.

The scenes displayed in the images show the transition zone between Iani Chaos and Ares Vallis. A chaotic distribution of individual blocks of rock and hills forms a disrupted pattern. These ‘knobs’ are several hundred metres high. Scientists suggest that they are remnants of a pre-existing landscape that collapsed after cavities had formed beneath the surface.

The elongated curvature of features extending from south to north along with terraces, streamlined 'islands' and the smooth, flat surface in the valley centre are strong hints that it was running water that carved the valley.

Ice stored in possible cavities in the Martian highlands might have been melted by volcanic heat. Pouring out, the melting water would have followed the pre-existing topography to the northern lowlands.

A hundred kilometres further north, a ten-kilometre-wide valley arm merges into Ares Vallis from the west. Large amounts of water originating from Aram Chaos (outside the image) joined the stream of Ares Vallis. Fan-shaped deposits on the valley floor are the remnants of landslides at the northern flanks.

At the freshly eroded cliffs, possible lava layers are visible: such layers are found almost everywhere in Xanthe Terra. Further downstream, another valley branch enters Ares Vallis from the east after passing through an eroded impact crater in Xanthe Terra. West of Ares Vallis, a more subtle riverbed is running parallel to the main valley.

The black and white images were taken by the nadir (vertical view) channel. The colour scenes were processed using the three colour channels and the nadir channel. The perspective views were derived from the digital terrain model based on the stereo channels, and then combined with the colour channels.

The 3D image was processed from the nadir and one stereo channel. Image resolution have been reduced for use on the internet. The 'flyover' video is based on the digital terrain model from the stereo channels and the colour data.

This story has been adapted from a news release issued by European Space Agency.

 [ send green star]

"In a two-day orbit, it's about 200 degrees Celsius too hot for liquid water," Butler said. "That tends to lead us to the conclusion that the most probable composition of this thing is like the inner planets of this solar system - a nickel/iron rock, a rocky planet, a terrestrial planet."

"The planet's mass could easily hold onto an atmosphere," noted Laughlin, an assistant professor of astronomy at UC Santa Cruz. "It would still be considered a rocky planet, probably with an iron core and a silicon mantle. It could even have a dense steamy water layer. I think what we are seeing here is something that's intermediate between a true terrestrial planet like the Earth and a hot version of the ice giants Uranus and Neptune."

A paper detailing the team's results has been submitted to The Astrophysical Journal. Coauthors on the paper are Steven Vogt and Gregory Laughlin of the Lick Observatory at the University of California, Santa Cruz; Debra Fischer of San Francisco State University; and Timothy M. Brown of NSF's National Center for Atmospheric Research in Boulder, Colo.

Combined with improved computer software, the new CCD detectors designed by this team for Keck's HIRES spectrometer can now measure the Doppler velocity of a star to within one meter per second - human walking speed - instead of the previous precision of 3 meters per second. This improved sensitivity will allow the planet-hunting team to detect the gravitational effect of an Earth-like planet within the habitable zone of M dwarf stars like Gliese 876.

"We are pushing a whole new regime at Keck to achieve one meter per second precision, triple our old precision, that should also allow us to see Earth-mass planets around sun-like stars within the next few years," Butler said.

"Our UC Santa Cruz and Lick Observatory team has done an enormous amount of optical and technical and detector work to make the Keck telescope a rocky planet hunter, the best one in the world," Marcy added.

Lissauer also is excited by another feat reported in the paper submitted to The Astrophysical Journal. For the first time, he, Rivera and Laughlin have determined the line-of-sight inclination of the orbit of the stellar system solely from the observed Doppler wobble of the star. Using dynamical models of how the two Jupiter-size planets interact, they were able to calculate the masses of the two giant planets from the observed shapes and precession rates of their oval orbits. Precession is the slow turning of the long axis of a planet's elliptical orbit.

They showed that the orbital plane is tilted 40 degrees to our line of sight. This allowed the team to estimate the most likely mass of the third planet as 7.5 Earth masses.

"There's more dynamical modeling involved in this study than any previous study, much more," Lissauer said.

The team plans to continue to observe the star Gliese 876, but is eager to find other terrestrial planets among the 150 or more M dwarf planets they observe regularly with Keck.

"So far, we find almost no Jupiter mass planets among the M dwarf stars we've been observing, which suggests that, instead, there is going to be a large population of smaller mass planets," Butler noted.

The astronomers' research was supported by NSF, the National Aeronautics and Space Administration, the University of California and the Carnegie Institution of Washington.

 [ send green star]

Arlington, Va. - The world's preeminent planet hunters have discovered the most Earth-like extrasolar planet yet: a possibly rocky world about 7.5 times as massive as the Earth.

This hot "super-Earth," just 15 light years away, travels in a nearly circular orbit only 2 million miles from its parent star, Gliese 876, and has a radius about twice that of Earth.

All the nearly 150 extrasolar planets discovered to date that are orbiting normal stars have been larger than Uranus, an ice giant about 15 times the mass of Earth.

"This is the smallest extrasolar planet yet detected and the first of a new class of rocky terrestrial planets," said team member Paul Butler of the Carnegie Institution in Washington. "It's like Earth's bigger cousin."

"This planet answers an ancient question," said team leader Geoffrey Marcy, professor of astronomy at the University of California, Berkeley. "Over 2,000 years ago, the Greek philosophers Aristotle and Epicurus argued about whether there were other Earth-like planets. Now, for the first time, we have evidence for a rocky planet around a normal star."

Marcy, Butler, theoretical astronomer Jack Lissauer of NASA/Ames Research Center, and post-doctoral researcher Eugenio J. Rivera of the University of California Observatories/Lick Observatory at UC Santa Cruz presented their findings today (Monday, June 13) during a press conference at the National Science Foundation (NSF) in Arlington, Va.

Part of a system that includes two other Jupiter-size planets, the new rocky planet whips around its star in a mere two days, and is so close to the star's surface that the astronomers say its temperature probably tops 200 to 400 degrees Celsius (400 to 750 degrees Fahrenheit) - oven temperatures far too hot for life as we know it.

Nevertheless, the ability to detect the tiny wobble that the planet induces in the star gives them confidence that they will be able to discover even smaller rocky planets in orbits more hospitable to life.

The team measures a minimum mass of 5.9 Earth masses for the new planet, which is orbiting Gliese 876 with a period of 1.94 days at a distance of 0.021 astronomical units (AU), or 2 million miles.

Though the team has no proof that the planet is rocky, its low mass precludes it from retaining gas like Jupiter. Three other purportedly rocky extrasolar planets have been reported, but they orbit a pulsar, the flashing corpse of an exploded star.

Gliese 876 (or GJ 876) is a small, red star known as an M dwarf � the most common type of star in the galaxy. It is located in the constellation Aquarius, and, at about one-third the mass of the sun, is the smallest star around which planets have been discovered. Butler and Marcy detected the first planet in 1998, and it proved to be a gas giant about twice the mass of Jupiter. Then, in 2001, they reported a second planet, another gas giant about half the mass of Jupiter. The two are in resonant orbits, the outer planet taking 60 days to orbit the star, twice the period of the inner giant planet.

Data on the Gliese 876 system, gathered from research the astronomers conducted at the Keck Observatory in Hawaii, were analyzed by Lissauer and Rivera in order to model the unusual motions of the two known planets. Three years ago, they got an inkling that there might be a smaller, third planet orbiting the star. In fact, if they hadn't taken account of the resonant interaction between the two known planets, they never would have seen the third.

"We had a model for the two planets interacting with one another, but when we looked at the difference between the two-planet model and the actual data, we found a signature that could be interpreted as a third planet," Lissauer said.

A three-planet model consistently gave a better fit to the data, added Rivera. "But because the signal from this third planet was not very strong, we were very cautious about announcing a new planet until we had more data," he said.

Recent improvements to the Keck Telescope's high-resolution spectrometer (HIRE provided the crucial new data. Vogt, who designed and built HIRES, worked with the technical staff in the UC Observatories/Lick Observatory Laboratories at UC Santa Cruz to upgrade the spectrometer's CCD (charge coupled device) detectors last August.

"It is the higher precision data from the upgraded HIRES that gives us confidence in this result," Butler said.

The team now has convincing data for the planet orbiting very close to the star, at a distance of about 10 stellar radii. That's less than one-tenth the size of Mercury's orbit in our solar system.

 [ send green star]

NASA's Opportunity Rover Rolls Free On Mars

Engineers and mission managers for NASA's Mars Exploration Rover mission cheered when images from the Martian surface confirmed Opportunity had successfully escaped from a sand trap.

From about 174 million kilometers away (about 108 million miles), the rover team at NASA's Jet Propulsion Laboratory, Pasadena, Calif., had worked diligently for nearly five weeks to extricate the rover. The long-distance roadside assistance was a painstaking operation to free all six wheels of the rover, which were mired up to their rims in the soft sand of a small martian dune.

"After a nerve-wracking month of hard work, the rover team is both elated and relieved to finally see our wheels sitting on top of the sand instead of half buried in it," said Jeffrey Biesiadecki, a JPL rover mobility engineer.

Traction was difficult in the ripple-shaped dune of windblown dust and sand that Opportunity drove into on April 26. In the weeks following, the rover churned 192 meters (629 feet) worth of wheel rotations before gaining enough traction to actually move one meter (about three feet). The rover team directed the drives in cautious increments from May 13 through June 4.

"We did careful testing for how to get Opportunity out of the sand. Then we patiently followed the strategy developed from the testing, monitoring every step of the way," Biesiadecki said. "We hope to have Opportunity busy with a full schedule of scientific exploration again shortly."

Opportunity's next task is to examine the site to provide a better understanding of what makes that ripple different from the dozens of similar ones the rover easily crossed. "After we analyze this area, we'll be able to plan safer driving in the terrain ahead," said JPL's Jim Erickson, rover project manager.

Both Spirit and Opportunity have worked in harsh martian conditions much longer than anticipated. They have been studying geology on opposite sides of Mars for more than a year of extended missions since successfully completing their three-month primary missions in April 2004.

"The first thing we're going to do is simply take a hard look at the stuff we were stuck in," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y. He is the principal investigator for the Mars rovers' science instruments. "After that, we will begin a cautious set of moves to get us on our way southward again. South is where we think the best science is, so that's still where we want to go."

Shortly after landing in January 2004, Opportunity found layered bedrock that bore geological evidence for a shallow ancient sea. Spirit did not find extensive layered bedrock until more than a year later, after driving more than two miles and climbing into a range of hills known as "Columbia Hills."

This story has been adapted from a news release issued by NASA/Jet Propulsion Laboratory.

 [ send green star]

It was a day like any other for a nearby star named GJ 3685A - until it suddenly exploded with light. At 2 p.m. Pacific time on April 24, 2004, the detectors on NASA's Galaxy Evolution Explorer ultraviolet space telescope nearly overloaded when the star abruptly brightened by a factor of at least 10,000. After the excitement was over, astronomers realized that they had just recorded a giant star eruption, or flare, about one million times more energetic than those from our Sun.

This dramatic flare is just one of many serendipitous discoveries made by the Galaxy Evolution Explorer since its 2003 launch.

Though the telescope was originally designed to spot galaxies, it has repeatedly witnessed a sky flickering with ultraviolet flares, bursts and fast-moving streaks. While the flares and bursts are from different types of stars, the streaks are asteroids, satellites or possibly space debris floating across the telescope's field of view.

The findings have led astronomers to conclude that the ultraviolet sky, once thought to be a quiet backdrop for viewing galaxies, is, in fact, a rather festive place.

"We had no idea that the ultraviolet sky would be filled with so many things that go bump in the night," said Dr. Barry Welsh, University of California, Berkeley, co-discoverer of some of the flares. "All of these objects are a bonus to astronomers, since the observations come free when the telescope is aimed at distant galaxies."

"I was surprised by how often we have observed stellar flares and by the amazing size of some of them," said Dr. Chris Martin, principal investigator of the Galaxy Evolution Explorer, California Institute of Technology, Pasadena. "Nature rarely disappoints us."

So far, the Galaxy Evolution Explorer has recorded 84 bonus astrophysical events occurring on flaring stars, binary stars called dwarf novae, and pulsating stars, as well as countless pieces of space debris. These data are already being collected into public databases for other astronomers to study. For example, astronomers are using the new set of flare stars to test their flare theories.

The Galaxy Evolution Explorer is surveying the entire sky at ultraviolet wavelengths for clues to how the earliest galaxies evolved into mature galaxies like our own Milky Way. To detect these early, faint galaxies, the telescope was outfitted with specialized cameras that allow the arrival of each photon of ultraviolet light to be timed with a precision of about a microsecond.

"The telescope's detectors have provided an unprecedented time resolution of these astrophysical events," said Welsh. "Now, we can say what happens during each one-hundredth of a second of a flare event. That's better information than most video cameras have when they take slow motion shots of athletes."

A preliminary analysis of the enormous flare witnessed by the Galaxy Evolution Explorer around GJ 3685A - the largest ever recorded in ultraviolet light - shows that the mechanisms underlying these stellar eruptions may be more complex than previously believed. Evidence for the two most popular flare theories was found.

Flares are huge explosions of energy stemming from a single location on a star's surface. They happen regularly on many types of stars, though old, small "red dwarf" stars like GJ 3685A tend to experience them most frequently and dramatically. These stars, called flare stars, can erupt as often as every few hours, and with an intensity far greater than flares from our Sun. One of the reasons astronomers study flare stars is to gain a better picture and history of flare events taking place on the Sun.

Caltech leads the Galaxy Evolution Explorer mission and is responsible for science operations and data analysis. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the mission and built the science instrument. The mission was developed under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. South Korea and France are the international partners in the mission.

This story has been adapted from a news release issued by NASA/Jet Propulsion Laboratory.

 [ send green star]

I found this article on the NASA site..

Discovery Shuttle May Roll Back to Pad Early, NASA Says
By Chris Kridler
 2 June 2005

 [ send green star]

"Finding all these stars in an orderly rotation was the last explanation anyone would think of," says Chapman.

On the flip side, finding that the bulk of the complex structure in Andromeda's outer region is rotating with the disk is a blessing for studying the true underlying stellar halo of the galaxy. Using this new information, the researchers have been able to carefully measure the random motions of stars in the stellar halo, probing its mass and the form of the elusive dark matter that surrounds it.

Although the main work was done at the Keck Observatory, the original images that posed the possibility of an extended disk were taken with the Isaac Newton Telescope's Wide-Field Camera. The telescope, located in the Canary Islands, is intended for surveys, and in the case of this study, served well as a companion instrument.

Chapman says that further work will be needed to determine whether the extended disk is merely a quirk of the Andromeda galaxy, or is perhaps typical of other galaxies.

The main paper with which today's AAS news conference is concerned will be published this year in The Astrophysical Journal with the title "On the Accretion Origin of a Vast Extended Stellar Disk Around the Andromeda Galaxy." In addition to Chapman and Ibata, the other authors are Annette Ferguson, University of Edinburgh; Geraint Lewis, University of Sydney; Mike Irwin, Cambridge University; and Nial Tanvir, University of Hertfordshire.

This story has been adapted from a news release issued by California Institute Of Technology.

 [ send green star]

Andromeda Galaxy Three Times Bigger In Diameter Than Previously Thought

MINNEAPOLIS -- The lovely Andromeda galaxy appeared as a warm fuzzy blob to the ancients. To modern astronomers millennia later, it appeared as an excellent opportunity to better understand the universe. In the latter regard, our nearest galactic neighbor is a gift that keeps on giving.

Scott Chapman, from the California Institute of Technology, and Rodrigo Ibata, from the Observatoire Astronomique de Strasbourg in France, have led a team of astronomers in a project to map out the detailed motions of stars in the outskirts of the Andromeda galaxy. Their recent observations with the Keck telescopes show that the tenuous sprinkle of stars extending outward from the galaxy are actually part of the main disk itself. This means that the spiral disk of stars in Andromeda is three times larger in diameter than previously estimated.

At the annual summer meeting of the American Astronomical Society today, Chapman will outline the evidence that there is a vast, extended stellar disk that makes the galaxy more than 220,000 light-years in diameter. Previously, astronomers looking at the visible evidence thought Andromeda was about 70,000 to 80,000 light-years across. Andromeda itself is about 2 million light-years from Earth.

The new dimensional measure is based on the motions of about 3,000 of the stars some distance from the disk that were once thought to be merely the "halo" of stars in the region and not part of the disk itself. By taking very careful measurements of the "radial velocities," the researchers were able to determine precisely how each star was moving in relation to the galaxy.

The results showed that the outlying stars are sitting in the plane of the Andromeda disk itself and, moreover, are moving at a velocity that shows them to be in orbit around the center of the galaxy. In essence, this means that the disk of stars is vastly larger than previously known.

Further, the researchers have determined that the nature of the "inhomogeneous rotating disk"-in other words, the clumpy and blobby outer fringes of the disk-shows that Andromeda must be the result of satellite galaxies long ago slamming together. If that were not the case, the stars would be more evenly spaced.

Ibata says, "This giant disk discovery will be very hard to reconcile with computer simulations of forming galaxies. You just don't get giant rotating disks from the accretion of small galaxy fragments."

The current results, which are the subject of two papers already available and a third yet to be published, are made possible by technological advances in astrophysics. In this case, the Keck/DEIMOS multi-object spectrograph affixed to the Keck II Telescope possesses the mirror size and light-gathering capacity to image stars that are very faint, as well as the spectrographic sensitivity to obtain highly accurate radial velocities.

A spectrograph is necessary for the work because the motion of stars in a faraway galaxy can only be detected within reasonable human time spans by inferring whether the star is moving toward us or away from us. This can be accomplished because the light comes toward us in discrete frequencies due to the elements that make up the star.

If the star is moving toward us, then the light tends to cram together, so to speak, making the light higher in frequency and "bluer." If the star is moving away from us, the light has more breathing room and becomes lower in frequency and "redder."

If stars on one side of Andromeda appear to be coming toward us, while stars on the opposite side appear to be going away from us, then the stars can be assumed to orbit the central object.

The extended stellar disk has gone undetected in the past because stars that appear in the region of the disk could not be known to be a part of the disk until their motions were calculated. In addition, the inhomogeneous "fuzz" that makes up the extended disk does not look like a disk, but rather appears to be a fragmented, messy halo built up from many previous galaxies' crashing into Andromeda, and it was assumed that stars in this region would be going every which way.

 [ send green star]

Unveiling The High Energy Milky Way Reveals 'Dark Accelerators'

 the March 25th 2005 issue of Science Magazine, the High Energy Stereoscopic System (H.E.S.S.) team of international astrophysicists, including UK astronomers from the University of Durham, report results of a first sensitive survey of the central part of our galaxy in very high energy (VHE) gamma-rays. Included among the new objects discovered are two 'dark accelerators' - mysterious objects that are emitting energetic particles, yet apparently have no optical or x-ray counterpart.

This survey reveals a total of eight new sources of VHE gamma-rays in the disc of our Galaxy, essentially doubling the number known at these energies. The results have pushed astronomy into a previously unknown domain, extending our knowledge of the Milky Way in a novel wavelength regime thereby opening a new window on our galaxy.

Gamma-rays are produced in extreme cosmic particle accelerators such as supernova explosions and provide a unique view of the high energy processes at work in the Milky Way. VHE gamma-ray astronomy is still a young field and H.E.S.S. is conducting the first sensitive survey at this energy range, finding previously unknown sources.

Particularly stunning is that two of these new sources discovered by H.E.S.S. have no obvious counterparts in more conventional wavelength bands such as optical and X-ray astronomy. The discovery of VHE gamma-rays from such sources suggests that they may be 'dark accelerators', as Stefan Funk from the Max-Planck Institut in Heidelberg affirms: "These objects seem to only emit radiation in the highest energy bands. We had hoped that with a new instrument like H.E.S.S. we would detect some new sources, but the success we have now exceeds all our expectations."

Dr Paula Chadwick of the University of Durham adds "Many of the new objects seem to be known categories of sources, such as supernova remnants and pulsar wind nebulae. Data on these objects will help us to understand particle acceleration in our galaxy in more detail; but finding these 'dark accelerators' was a surprise. With no counterpart at other wavelengths, they are, for the moment, a complete mystery."

Cosmic particle accelerators are believed to accelerate charged particles, such as electrons and ions, by acting on these particles with strong shock waves. High-energy gamma rays are secondary products of the cosmic accelerators and are easier to detect because they travel in straight lines from the source, unlike charged particles which are deflected by magnetic fields. The cosmic accelerators are usually visible at other wavelengths as well as VHE gamma rays.

The H.E.S.S. array is ideal for finding these new VHE gamma ray objects, because as well as studying objects seen at other wavelengths that are expected to be sources of very high energy gamma rays, its wide field of view (ten times the diameter of the Moon) means that it can survey the sky and discover previously unknown sources.

Another important discovery is that the new sources appear with a typical size of the order of a tenth of a degree; the H.E.S.S. instrument for the first time provides sufficient resolution and sensitivity to see such structures. Since the objects cluster within a fraction of a degree from the plane of our Galaxy, they are most likely located at a significant distance - several 1000 light years from the sun - which implies that these cosmic particle accelerators extend over a size of light years.

The results were obtained using the High Energy Stereoscopic System (H.E.S.S.) telescopes in Namibia, in South-West Africa. This system of four 13 m diameter telescopes is currently the most sensitive detector of VHE gamma-rays, radiation a million million times more energetic than the visible light. These high energy gamma rays are quite rare - even for relatively strong sources, only about one gamma ray per month hits a square meter at the top of the earth's atmosphere. Also, since they are absorbed in the atmosphere, a direct detection of a significant number of the rare gamma rays would require a satellite of huge size. The H.E.S.S. telescopes employ a trick - they use the atmosphere as detector medium. When gamma rays are absorbed in the air, they emit short flashes of blue light, named Cherenkov light, lasting a few billionths of a second. This light is collected by the H.E.S.S. telescopes with big mirrors and extremely sensitive cameras and can be used to create images of astronomical objects as they appear in gamma-rays.

The H.E.S.S. telescopes represent several years of construction effort by an international team of more than 100 scientists and engineers from Germany, France, the UK, Ireland, the Czech Republic, Armenia, South Africa and the host country Namibia. The instrument was inaugurated in September 2004 by the Namibian Prime Minister, Theo-Ben Guirab, and its first data have already resulted in a number of important discoveries, including the first astronomical image of a supernova shock wave at the highest gamma-ray energies.

This story has been adapted from a news release issued by Particle Physics & Astronomy Research Council.

 [ send green star]

Voyager I Enters Solar System's Final Lap

Tue May 24, 8:39 PM ET

NASA's Voyager I spacecraft has entered the final frontier of our solar system and is cruising its way to a vast area marking the beginning of interstellar space.

The spacecraft, launched 28 years ago, is 8.7 billion miles from the sun in a region called the heliosheath, located just beyond the termination shock, or precursor of the boundary that marks the beginning of interstellar space.

"Voyager I has entered the final lap on its race to the edge of the interstellar space," said Edward Stone, project scientist at the California Institute of Technology in Pasadena, which manages NASA's Jet Propulsion Laboratory.

The findings were presented Tuesday at the American Geophysical Union meeting in New Orleans.

Voyager I still has a decade to go before reaching the heliopause, which marks the beginning of interstellar space and the end of our solar system. Beyond, it's the interstellar medium, made up of the particles cast off by dying stars.

There was disagreement in 2003 over whether the spacecraft penetrated the termination shock, where the solar wind slows abruptly, becoming denser and hotter.

Scientists said recent evidence shows the spacecraft's instruments recorded a sudden increase in the solar wind's magnetic field, which happens when the solar wind slows down.

Copyright © 2005 The Associated Press.

  The article above came from a yahoo news story and the picture is from http://voyager.jpl.nasa.gov/  if you would like to read more. 

Happy Stargazing

Davida

Hi Everyone,

 [ send green star]

Cassini Determines the Density of Saturn's Rings

Summary - (May 24, 2005) NASA's Cassini spacecraft has obtained the most detailed images ever taken of Saturn's rings, including new details about its B ring, of which little was known previously. Cassini went behind Saturn's rings on May 3, 2005, and this gave scientists on Earth a chance to probe the ringst. Cassini sent a series of radio signals as it traveled behind the rings; the weaker the signal, the more dense the material in the rings. This allowed scientists to determine the thickness and size of particles at each point in the rings.

Full Story -

Cassini image of Saturn's rings enhanced in false colours. Image credit: NASA/JPL/SSI.

The Cassini spacecraft has obtained the most detailed look ever at Saturn's rings, including the B ring, which has eluded previous robotic explorers. Its structure seems remarkably different from its two neighbors, rings A and C.

The origin of Saturn's rings is a mystery. The rings are an enormous, complex structure. From edge-to-edge, the ring system would not even fit in the distance between Earth and the Moon. The seven main rings are labeled in the order they were discovered. From the planet outward, they are D, C, B, A, F, G and E.

During a recent radio experiment, Cassini mapped this structure with clarity never before available. This is the first of many such observations Cassini will be conducting over the summer.

"The structure of those remarkable rings is a sight to behold. All ring features appear to be populated by a broad range of particle sizes that extend to many meters in diameter at the upper end," said Dr. Essam Marouf, Cassini radio science team member and professor of electrical engineering, San Jose State University, San Jose, Calif.

Marouf said that at the lower end, particles of about 5 centimeters (roughly 2 inches) in diameter or less seem to be scarce in ring B and inner ring A. In rings C and outer ring A, particles of less than about 5 centimeters (2 inches) in diameter seem to be abundant.

Cassini found that the inner and outer parts of ring B contain rings that are hundreds of kilometers wide (hundreds of miles) and vary greatly in the amount of material they contain. A thick, 5,000-kilometer-wide (3,100-mile) core contains several bands with ring material that is nearly four times as dense as that of ring A and nearly 20 times as dense as that of ring C.

The dramatically varying structure of ring B is in sharp contrast to the relatively flat structure of ring A or the gentle, wavy structure of ring C, where many dense, narrow and sharp-edged ringlets permeate its outer part.

Cassini also detected more than 40 wavy features called "density waves" in ring A, many near its outer region, close to the moons orbiting just outside the ring. The density wave observations will tell more about the ring surface mass density, its vertical thickness and other physical properties.

"A marvelous array of waves, caused by gravitational interactions with nearby moons, has been uncovered throughout ring A," said Marouf. "We also see a major density wave in the dense ring B. Some of these waves have been seen in Voyager and other Cassini observations, but not in this large number and not with this exceptional clarity."

Cassini conducted this first radio occultation observation of Saturn's rings, atmosphere and ionosphere on May 3, 2005. An occultation means that if you watch Cassini from Earth, Cassini would appear occulted, or hidden, behind the rings. During a radio occultation, Cassini sends a radio signal from the spacecraft through the rings to Earth. Scientists then watch how the strength of the radio signal is affected as the signal passes through ring material. The denser a ring is, the weaker the signal received. The experiment helps scientists map the distribution of the amount of ring material and determine the ring particle sizes.

The occultation was the first ever to use three radio signals of different frequencies (called Ka, X and transmitted simultaneously from a spacecraft to Earth-receiving stations of NASA's Deep Space Network. Ring particles of different sizes affect each frequency differently.

The Cassini tour was specifically designed to optimize the geometry of the first radio occultation experiment and seven other occultations scheduled from May to September 2005. These observations are at the heart of Cassini's fundamental science objectives of characterizing and understanding Saturn and its ring system. During its lifetime, Cassini will obtain 20 radio occultations and 80 stellar occultations, providing far more detailed knowledge of the ring structures.

For images and information on the Cassini mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL.

Original Source: NASA/JPL News Release

T/Space's ship differs from those proposed by the primes in one other important respect: it will fly paying passengers. After supplying NASA with the ships it needs, t/Space plans to offer flights to anyone who can afford them.

Space tourism is the prize most of the space entrepreneurs have their eyes on, and one of the biggest points of contention is how to safely fly well-heeled tourists and handle litigious relatives who don't take kindly to fatal accidents.

For Will Whitehorn, president of Virgin Galactic, the space tourism company started by Richard Branson last year, the best technology is obvious: a spaceship powered by a non-explosive mix of nitrous oxide and synthetic rubber launched from a high altitude airplane. This is the approach Scaled Composites used to create the world's first commercial astronaut last year, and the one that t/Space also champions.

But other companies, including Elon Musk's Space Exploration Technologies, or SpaceX, plan to fly passengers on good old-fashioned, two-stage rockets fueled by explosive kerosene and liquid oxygen.

That prospect keeps Whitehorn awake at night. If some garage rocket scientist blows himself up trying to get into space, the U.S. government may well put the brakes on the whole industry.

If that doesn't happen, Virgin Galactic plans to begin the first regularly scheduled passenger service to space in 2008. The first 100 passengers have already paid their deposits on $200,000 tickets.

The names of the lucky six to fly the first flight will be drawn from a hat, though they won't be on the inaugural flight -- that's reserved for Branson, Burt Rutan and Branson's nonagenarian father. And if you don't have 200 G's to spare? Branson's launching a new TV game show in which contestants will compete for rides.

Perhaps space entrepreneur Bob Richards summed up the tenor of the new spaceflight industry best during the ISDC's closing presentation. He likened the squabbling of its participants to the cacophony of an orchestra warming up; once in tune, the noise will turn to music, and space will never be the same.

 [ send green star]

Conflict at Space Confab 

By Michael Belfiore

02:00 AM May. 24, 2005 PT

 [ send green star]

Artist interpretation of an extrasolar planet. Image credit: NASA.

An international collaboration featuring Ohio State University astronomers has detected a planet in a solar system that, at roughly 15,000 light years from Earth, is one of the most distant ever discovered.
Andrew Gould

In a time when technology is starting to make such finds almost commonplace, this new planet -- which is roughly three times the size of Jupiter -- is special for several reasons, said Andrew Gould, professor of astronomy at Ohio State .

The technique that astronomers used to find the planet worked so well that he thinks it could be used to find much smaller planets -- Earth-sized planets, even very distant ones.

And because two amateur astronomers in New Zealand helped detect the planet using only their backyard telescopes, the find suggests that anyone can become a planet hunter.

Gould and his colleagues have submitted a paper announcing the planet to Astrophysical Journal Letters, and have posted the paper on a publicly available Internet preprint server, http://arXiv.org . The team has secured use of NASA's Hubble Space Telescope in late May to examine the star that the planet is orbiting.

The astronomers used a technique called gravitational microlensing, which occurs when a massive object in space, like a star or even a black hole, crosses in front of a star shining in the background. The object's strong gravitational pull bends the light rays from the more distant star and magnifies them like a lens. Here on Earth, we see the star get brighter as the lens crosses in front of it, and then fade as the lens gets farther away.
Because the scientists were able to monitor the light signal with near-perfect precision, Gould thinks the technique could easily have revealed an even smaller planet. "If an Earth-mass planet was in the same position, we would have been able to detect it," he said.

On March 17, 2005, Andrzej Udalski, professor of astronomy at Warsaw University and leader of the Optical Gravitational Lensing Experiment, or OGLE, noticed that a star located thousands of light years from Earth was starting to move in front of another star that was even farther away, near the center of our galaxy. A month later, when the more distant star had brightened a hundred-fold, astronomers from OGLE and from Gould's collaboration (the Microlensing Follow Up Network, or MicroFUN) detected a new pattern in the signal -- a rapid distortion of the brightening -- that could only mean one thing.

"There's absolutely no doubt that the star in front has a planet, which caused the deviation we saw," Gould said.

Because the scientists were able to monitor the light signal with near-perfect precision, Gould thinks the technique could easily have revealed an even smaller planet.

"If an Earth-mass planet was in the same position, we would have been able to detect it," he said.

OGLE finds more than 600 microlensing events per year using a dedicated 1.3-meter telescope at Las Campanas Observatory in Chile (operated by Carnegie Institution of Washington). MicroFUN is a collaboration of astronomers from the US, Korea, New Zealand, and Israel that picks out those events that are most likely to reveal planets and monitors them from telescopes around the world.

"That allows us to watch these events 24/7," Gould said. "When the sun rises at one location, we continue to monitor from the next."

Two of these telescopes belong to two avid New Zealand amateur astronomers who were recruited by the MicroFUN team. Grant Christie of Auckland used a 14-inch telescope, and Jennie McCormick of Pakuranga used a 10-inch telescope. Both share co-authorship on the paper submitted to Astrophysical Journal Letters.

Two other collaborations -- the Probing Lensing Anomalies NETwork (PLANET) and Microlensing Observations in Astrophysics (MOA) -- also followed the event and contributed to the journal paper.

SOHO image of the Sun that shows magnetic fields (yellow lines) and the solar wind (red arrows). Image credit: NASA/ESA.

A layer deep in the solar atmosphere can be used to estimate the speed of the solar wind, a stream of electrified gas that constantly blows from the Sun. Estimating the speed of the solar wind will improve space weather forecasts, which will aid human exploration of the planets.

The solar wind flows from the Sun's hot, thin, outer atmosphere, the "corona". The researchers were surprised to discover that the structure of the Sun's cooler, dense lower atmosphere, called the chromosphere, could be used to estimate the speed of the solar wind.

This was unexpected because the solar wind is a phenomenon of the corona, and the chromosphere is so deep -- it's the layer just above the Sun's visible surface. "It's like discovering that the source of the river Nile is another 500 miles inland," said Dr. Scott McIntosh of the Southwest Research Institute, Boulder, Colo., lead author of a paper on this research published May 10 in the Astrophysical Journal.

The new work promises to increase the accuracy of space radiation forecasts. The Sun occasionally launches billion-ton blasts of electrified gas, called coronal mass ejections (CMEs), into space at millions of miles (kilometers) per hour. If a fast CME is plowing through slow solar wind, a shock builds up in front of the CME that accelerates the electrically charged solar wind particles. These fast particles can disrupt satellites and are hazardous to unprotected astronauts.

"Just as knowing more details about the atmosphere helps to predict the intensity of a hurricane, knowing the speed of the solar wind helps to determine the intensity of space radiation storms from CMEs," said co-author Dr. Robert Leamon of L-3 Government Services at NASA's Goddard Space Flight Center, Greenbelt, Md.

Like wind on Earth, the solar wind is gusty, ranging in speed from about 750,000 miles per hour (approximately 350 km/second) to 1.5 million miles per hour (700 km/second).

Since the solar wind is made up of electrically-charged particles, it responds to magnetic fields that permeate the solar atmosphere. Solar wind particles flow along invisible lines of magnetic force like cars on a highway. When the magnetic field lines bend straight out into space, as they do in "coronal hole" regions, the solar wind acts like cars on a drag strip, racing along at high speed. When the magnetic field lines bend sharply back to the solar surface, like the pattern of iron filings around a bar magnet, the solar wind acts like cars in city traffic and emerges relatively slowly. Scientists have known this for over thirty years and used it to give a crude estimate for the speed of the solar wind -- either fast or slow.

In the new work, the team has tied the speed of the solar wind as it blows past Earth to variations deeper in the solar atmosphere than had previously been detected (or even expected). By measuring the time taken for a sound wave to travel between two heights in the chromosphere, they were able to determine that the chromosphere is effectively "stretched thin" below coronal holes with their open magnetic fields, but compressed below magnetically closed regions.

The team used the observation to derive a continuous range of solar wind speeds from the structure of the chromosphere. The wider the chromospheric layer is, the more it is being allowed to expand by open magnetic fields and the faster the solar wind will blow. This new method is more precise than the old "fast or slow" estimate.

NASA's Transition Region and Coronal Explorer (TRACE) spacecraft was used to measure the speed of sound waves in the chromosphere, and NASA's Advanced Composition Explorer (ACE) spacecraft was used to take measurements of the solar wind speed as it blew by the Earth. Comparing the data from the two spacecraft gave the connection.

 [report anonymous abuse]

"If Congress knew it would cost $5 billion up front, would they ever have funded it? No way," maintains Christopher Paine, who has monitored NIF's development for the Natural Resources Defense Council, an environment advocacy group, and has been one of its sharpest critics.

Despite its price escalation and remaining uncertainties, NIF maintains strong support in both Congress and the Bush administration. However, there have been other high-energy physics projects on which billions of dollars have been spent only to be dumped.

Congress pulled the plug in 1993 on the Superconducting Super Collider project, a racetrack-like device in Texas to study elementary particles and forces, after spending $2 billion. The Clinch River Breeder Reactor project in Tennessee was canceled a decade earlier after $1.7 billion had been spent as the United States abandoned nuclear fuel reprocessing. Both projects had large cost overruns.

Paine, who in a critique once dubbed NIF "The Unlovable Laser," maintains that NIF should follow the same path. He says it isn't needed and poses a nuclear proliferation risk because it might make it easier in decades ahead to develop new nuclear weapons, not just maintain existing ones.

The JASONs, a group of scientists frequently called upon to review complex defense or national security issues, has concluded that NIF "does not represent a significant proliferation risk" and is "fully compatible" with U.S. nonproliferation goals.

Still, a recent report by the Defense Science Board, which advises the Pentagon, urged more openness about NIF activities and a mix of civilian and defense NIF experiments to ease any public concerns about the laser's purpose.

The question of openness has been an issue before.

The program's critics charge that Livermore officials lowballed NIF's capabilities and potential cost from the beginning. When Congress was sold on NIF's importance because of its ability to simulate a nuclear explosion, scientists were at best only half certain fusion ignition could be accomplished, NIF program supporters acknowledge today.

Three years after NIF construction began, congressional auditors concluded in a 2000 report, "Congress cannot know with assurance just how much NIF will cost ... what impact NIF will have on the overall nuclear weapons program, or how long it will take to complete."

That report and others were prompted by discovery in late 1999 that engineers had encountered a serious problem installing the laser's optics and had hidden it from senior Energy Department officials and Congress.

In short, they could not keep the optics free of dust. To fix the problem would add $350 million to the project's cost. Even as engineers scrambled to try to find a solution, Livermore officials were telling then-Energy Secretary Bill Richardson that the program was on schedule and within budget.

"I remember being shell-shocked," Richardson said in an interview. "I had just been at the facility the month before and I had been briefed and pronounced (the laser program) in sound shape, a vision for the future."

It didn't help that NIF's project director also had just resigned after it was discovered he never completed work on a doctoral thesis and that a string of outside reviewers failed to identify any shortcomings with the project.

"The problem was, we had people doing this that did not appreciate the scale of what they were attempting to do," says Moses, a laser engineer and longtime senior manager at Livermore, who was brought in to lead the NIF program in late 1999. Those who had the vision of NIF found it was more complicated when it came to actually building it, he said.

The new team tackled a variety of problems.

By 2003, the dust issue was solved by building a massive clean room and installing the optics in modular dust-free units. Engineers found new ways to produce the thousands of highly polished pieces of laser glass. A faster way was found to grow high-quality crystals that convert the beams to ultraviolet just before they strike the target.

And with four of the planned 192 beams operating, new tests suggested strongly that when the system was fully operating, enough energy would be produced to - theoretically, at least - achieve ignition.

Last year, however, a new complication emerged - not over the laser but the pea-size pellet that contains the hydrogen fuel that will be ignited by the lasers to achieve fusion ignition. Could the pellet be manufactured to the required specifications?

Once its shell was to be made of plastic, but that idea was abandoned. Now the choice is beryllium, a metallic element that can withstand intense heat, is molecularly stable and is a good conductor.

It still is uncertain whether beryllium can be machined to specification, according to technicians who have monitored the program. Last year Congress directed another outside review to report how the development of a beryllium target might affect NIF's timetable.

Like previous challenges in the project's history, the beryllium issue will be resolved, Miller and Moses believe.

While the massive laser may one day have a broad range of scientific uses - some not even envisioned by today's scientists - the immediate focus remains assuring the reliability of the nation's nuclear arsenal without actually testing the weapons.

"It gives us confidence that the nuclear stockpile stewardship approach will work," Miller says.

---

On the Net:

National Ignition Facility: http://www.llnl.gov/nif

Natural Resources Defense Council: http://www.nrdc.org/nuclear/nif/nifinx.asp

Video of the National Ignition Facility is available at http://wid.ap.org/video/laser.rm

Copyright 2005 Associated Press. All rights reserved  [ send green star]

Study Explains Mystery Of Mars Icecaps

CORVALLIS, Ore. (May 11, 2005) -- An interdisciplinary team of scientists thinks it has an answer to a long-standing mystery of why the permanent icecap on Mars' South Pole is offset from the pole itself. Simply put, it's colder and stormier in that hemisphere.

But that is only part of the equation, scientists say, and new understanding about Mars' climate and its polar regions may suggest clues to finding water in the planet's equatorial zone - where it would be easier to land a spacecraft - and opening the door to future exploration and the search for life.

They reported their findings today in the journal Nature.

Jeffrey Barnes, a professor of atmospheric sciences at Oregon State University and one of the authors of the study, said the permanent icecaps on Mars' poles are quite different. The icecap on the northern pole is much larger - about the size of Greenland - and comprised primarily of water ice.

"The South Pole, however, is a strange animal," Barnes said. "The cap is made up mostly of carbon dioxide ice - or dry ice - which is the main component of the Martian atmosphere. The southern icecap is much smaller, about a 10th the size of that at the northern pole, and it is all on one side of the pole. The other side of the pole contains a much larger area known as 'the Cryptic Region,' which is made up of seasonal ice in the winter but has low albedo, or reflectivity.

"And no one has been able to figure out why there is this peculiar distribution of ice deposits."

The scientists were able to use images from the Mars Global Surveyor, temperature information, and climate models to develop a new theory.

"We basically think the Cryptic Region is a sheet of incredibly clear ice," Barnes said. "The reason for the low reflectivity is that the ground beneath the ice shows up right through it."

Other scientists in the study included lead author Anthony Colaprete, of the NASA Ames Research Center; Robert M. Haberle and Jeffery L. Hollingsworth, NASA Ames and San Jose State University; and Hugh H. Kieffer and Timothy N. Titus, the U.S. Geological Survey.

The southern pole's permanent icecap is in the western hemisphere, which is stormy during Martian winters and receives a lot of snowfall that comes in the form of carbon dioxide (C02) particles. These are very bright and highly reflective, creating a visible permanent icecap as well as much more extensive seasonal deposits.

The eastern hemisphere is comparatively warmer and rarely has storms. The scientists believe that instead of falling in the form of snow, the CO2 from the Mars atmosphere condenses right on the ground and forms slab ice, which is clear. They think the slab is about one meter deep.

C02 ice requires much colder temperatures - down to minus-125 degrees centigrade - than does the water ice at the northern pole.

Snow falling in just one hemisphere of the southern pole can be explained by Mars' asymmetrical climate in the south, Barnes said. The planet's topography is severe, and the different features strongly affect climate just as they do on Earth.

Mars has the highest volcano system in the solar system - the 85,000-foot high Olympus Mons and others of nearly that height. The southern hemisphere also is home to the Valles Marineris Canyon, which is six to seven kilometers deep and the length of the United States. The Hellas Basin is even deeper, at 10 kilometers, or more than six miles.

"The planet has huge volcanoes and mountains that extend from well north of the equator to the southern hemisphere, and two gigantic basins in the south," Barnes said. "The wind blowing over these topographic features sets up large-scale patterns that have a profound impact on the climate. Mars has weather systems much like the Earth, with traveling high- and low-pressure systems, and warm and cold fronts."

Barnes said there is evidence that the C02 ice in the permanent south cap is eroding, raising the possibility of global climate change. The area of the icecap has not shrunk, but features within it are diminishing and the depth may be decreasing as well, he said.

Disappearance of the southern CO2 icecap could indicate a very significant change in Mars' climate, pointed out Barnes, whose research specialty is the Martian atmosphere. Scientists think the icecaps are relatively young because they lack craters. They also say that Mars probably has a volatile climatic history, triggered by changes in the tilt of its axis and its pattern of orbit around the sun.

"Scientists think that the ice ages on Earth were triggered by small changes in the tilt of the Earth's axis and its orbit - over tens and hundreds of thousands of years," Barnes said. "Mars has undergone similar changes, but much, much larger. Earth tilts at about 23 degrees and Mars has about a 25-degree tilt. But in its past, Mars has tilted as much as 60 degrees and as little as zero degrees.

"Its orbital pattern changed dramatically, too," he added. "That would have a major impact on temperatures, climate, and icecaps."

During these major changes, Mars may have had enormous seasonal icecaps that extended nearly to its equator - or the permanent polar icecaps may have completely melted away. Learning more about the pattern of ice formation and melting may lead scientists to find deposits of water ice close to the equator, where it is easie  [ send green star]

 [ send green star]

"What goes up must come down". Ever since astronauts started playing games in space, for instance catching morsels of food floating in weightlessness conditions, the general public knows that the saying is not necessarily true.

Conditions of weightlessness may be obtained for short periods without going into orbit: from a few seconds to a few minutes.

But microgravity conditions can also be recreated for a few seconds on Earth. First stop, the European Space Agency's Research & Technology Centre (ESTEC) at Noordwijk in the Netherlands. In its Erasmus building, some uncanny things happen in an elegant woven-metal structure 13-metres tall.

The installation called a drop tower demonstrator was inaugurated last November. A capsule containing an experiment is allowed to drop down the structure and will experience weightlessness for 1.5 seconds before its fall is cushioned in a 1.75 metre deep pit filled with PVC spheres.

The ESTEC drop tower is not primarily used for scientific research but as a demonstrator of gravitational effects for students and an interested public and to explain the function of the Zarm drop tower at the University of Bremen in Germany.

"The 9 seconds of free-fall that are achieved at the drop-tower of ZARM may not seem long compared to the 25 seconds of parabolic flights or 12 minutes of sounding rockets , but it is enough to give experimenters a good idea of the phenomena they are investigating," comments ESA's Massimo Sabbatini.

"It can be a first step before launching on a Russian Foton capsule orbited by the Soyuz launcher which will provide 12 days of microgravity before returning to Earth, or even longer durations on the International Space Station."

"Scientists have realised that phenomena such as hydrostatic pressure, sedimentation or convection that are driven by gravity actually mask other phenomena that tend to be ignored or neglected," explains Olivier Minster, Head of the Physical Sciences Unit at ESA. "Freeing ourselves from the influence of gravity enables us to understand and eventually master these hidden phenomena at work in more complex systems."

EuroNews visited the ZARM facility, a working laboratory and one of the most important facilities for Europe's microgravity programme, unique in Europe with its impressive 146 metre tower.

Every day a large canister is prepared with its sensors and cameras and the various experiments to be observed or tested in conditions of weightlessness. The 400-kg capsule is then hoisted up the tower shaft, and its rapid 110-metre descent is monitored from a control centre. Each free fall offers 4.7 seconds of weightlessness and a catapult-like option at its base offers 9 seconds of weightlessness.

"The quality of the microgravity we obtain with the Zarm tower is exceptional, in fact a hundred times better than on the Space Station whose microgravity conditions are perturbed by the human presence," explained Hansjörg Dittus, the Zarm tower's deputy Director.

"In addition, if the experiments can be scaled down they react faster and you conduct about 80% of the experiments you can carry out in the Space Station. But one needs both: the tower to prepare all the experiments and the ISS or orbital systems to make a complete investigation."

Innovation is a constant in today's highly technical society. Attention to detail on small things leads to big achievements. The EuroNews report on European ground-based microgravity facilities evokes one of Europe's most recent shining examples : the first flight of the A380 Airbus, a powerhouse of technology.

The use of microgravity facilities, drop towers on Earth, or long duration flights in space, is an increasingly important domain in research technology, as Olivier Minster concludes. "Industrial competition is often driven by very small developments, details which make all the difference between rival products or processes. Microgravity experiments increase our understanding and can play a vital role."

Editor's Note: The original news release can be found here.

This story has been adapted from a news release issued by European Space Agency.

 [ send green star]

Thanks to a manoeuvre performed on 10 May 2005 at 20:20 CET, ESA flight controllers have successfully completed the deployment of the first boom of the MARSIS radar on board ESA's Mars Express spacecraft.

After the start of the deployment of the first 20-metre boom on 4 May, analysis by flight controllers at ESA’s European Space Operations Centre, Darmstadt, Germany, had shown that although 12 out of the 13 boom segments were in place, one of the outermost segments, possibly No. 10, had deployed but was not locked into position.

Deployment of the second (20 m) and third (7 m) booms was suspended pending a full analysis and assessment of the situation.

As prolonged storage in the cold conditions of outer space could affect the fibreglass and Kevlar material of the boom, the mission team decided to ‘slew’ (or swing) the 680 kg spacecraft so that the Sun would heat the cold side of the boom. It was hoped that as the cold side expanded in the heat, it would force the unlocked segment into place.

After an hour, Mars Express was pointed back to Earth, and contact re-established at 04:50 CET on 11 May. A detailed analysis of the data received showed that all segments had successfully locked and Boom 1 was fully deployed.

The operations to deploy the remaining two booms could be resumed in a few weeks, after a thorough analysis and investigation of the Boom 1 deployment characteristics.

The Mars Express Sub-Surface Sounding Radar Altimeter (MARSI experiment is to map the Martian sub-surface structure to a depth of a few kilometres. The instrument's 40-metre long antenna booms will send low frequency radio waves towards the planet, which will be reflected from any surface they encounter.

MARSIS is one of the seven science experiments carried on board Mars Express, one of the most successful missions ever flown to the Red Planet. Mars Express was launched on 2 June 2003 and entered Mars orbit in December 2003.

Editor's Note: The original news release can be found here.

This story has been adapted from a news release issued by European Space Agency.

 [ send green star]