Comet ISON is already remarkably bright and active,
a new set of photos shows, but it's still too early to tell
if ISON will live up to the "comet of the century" hype,
researchers stress. http://bit.ly/10CW5KV
Below, images of Comet ISON on February 4,
March 4, April 3, and May 4, 2013 (left to right, respectively).