By Irene Klotz CAPE CANAVERAL, Florida (Reuters) - Astronomers slated to meet this week to discuss observing plans for Comet ISON may not have much to talk about. The so-called "Comet of the Century" may already have fizzled out. "The future of comet ISON does not look bright," astronomer Ignacio Ferrin, with the University of Antioquia in Colombia, said in a statement on Monday. Ferrin's calculations show the comet, which is currently moving toward the sun at 16 miles per second, has not brightened since mid-January. ...