NASA brought the big gun to bear on our lost comet. On December 18, the Hubble Space Telescope slewed to Comet ISON's expected position and found nothing down to magnitude 25.

ISON is currently visible in the constellation Virgo. The best time to see it is early on a clear morning. Astronomers have monitored Comet ISON (C/2012) since it was discovered last year. Its ...

Comet ISON was first spotted by a Russian telescope in September last year. While many comets come out of the Oort cloud and return after a long trip through the solar system and many comets graze ...

The Comet ISON appears to have survived after disappearing and being thought dead. New NASA photos show the comet emerging from behind the sun smaller and dimmer, but still throwing a big light trail.

The other test that comet ISON must pass is to survive the tidal forces of the Sun, which will try to pull comet ISON apart as it flies by. The important property for this is the comet’s density.

Since the discovery of Comet ISON in September 2012, astronomers worldwide have eagerly anticipated its peak performance in late 2013. Many have high hopes that ISON will turn out to be a glorious ...

On NASA's Comet ISON Observing Campaign website, astrophysicist Karl Battams writes that ISON was "born 4.5 billion BC, fragmented Nov. 28, 2013 (age 4.5 billion yrs old)." ...

Comet ISON looks like a tadpole in the video, but we all know that tiny tadpoles grow into big green frogs. So will the comet when it brightens to naked eye visibility later this year.

Since Comet ISON's tumultuous close approach to the sun on Thursday, scientists have been working to determine whether it still exists or is now nothing more than dust.

Since its discovery in September 2012, Comet ISON has been full of surprises. It started off extremely bright, considering its great distance from the sun at the time, beyond Jupiter's orbit.

(Update: Thanksgiving Day, 2:18 PM ET: Astronomers working with NASA’s Comet ISON Observing Campaign (CIOC) continue to monitor ISON’s progress as it swings around the sun. No word yet on its ...