Story highlights
- NASA telescopes are hunting ISON's remnants
- A chunk of the comet may have survived
- Comet-watchers are not giving up on ISON
In case you missed it, a comet grazed the sun on Thanksgiving Day. Expectations had been high that Comet ISON would survive this close encounter, swing around the sun and put on a fantastic sky show. It was hoped it might even become a Great Comet, with massive tails visible to the naked eye.
But something really bad happened and now it looks like ISON may be just dust in the solar wind (the sun was uninjured, FYI). Here's what we know now about ISON:
1. Is ISON dead?
Well, maybe. After the comet flew about 730,000 miles above the sun's surface, it started fading in images taken by NASA spacecraft. Things got so bad that Karl Battams, an astrophysicist with the U.S. Naval Research Laboratory and one of ISON's top fans, er -- chief observers -- wrote an obit for the comet.
Despite the eulogy, Battams said we have to wait for the Hubble Space Telescope or other telescopes to confirm ISON's fate. "It seems unlikely at this stage that anything of significant size remains but Hubble observations would help clear that up," Battams told CNN in an e-mail.
NASA also hinted there may be a bit of hope for ISON in its latest update posted online Wednesday. The agency said it will use space telescopes to monitor ISON for the next several weeks because it's possible that dust is hiding a new, smaller version of it.
"Most agree that up to 90% of ISON was destroyed, leaving approximately 10% of the comet intact. If previous sungrazing comets are any guides, there may be a sizeable piece of comet nucleus left. At this point, though, scientists are waiting for a variety of telescopes to make observations before the status of Comet ISON can be confirmed."
2. What do we call ISON now?
"I don't think there is an official term yet," Battams said. "I have been referring to it as a comet remnant, and that seems pretty appropriate."
3. ISON wasn't a flop.
Okay, it won't be a "Great Comet" or the "Comet of the Century." But ISON did become a social media superstar and it gave scientists tons of data. "It's disappointing that we didn't get a spectacular naked-eye comet," Matthew Knight of Comet ISON Observing Campaign said in a NASA science article. "But in other ways I think Comet ISON was a huge success. The way people connected with Comet ISON via social media was phenomenal; our Comet ISON Observing Campaign website earned well over a million hits; and I had trouble downloading images near perihelion because NASA's servers were swamped.
"So maybe ISON was the 'Comet of the New Century,'" he said.
4. ISON won't be forgotten.
ISON's fate has become a near obsession for a special Facebook group set up by physicist and astronomer Padma Yanamandra-Fisher with the Space Science Institute and the ISON observing campaign. More than 300 members have been tracking the comet and sharing amazing pictures. Many are still looking for ISON's remains and they aren't ready to declare it dead.
"I think the evidence shows that something catastrophic happened to the comet, but I don't think anyone is 100% sure," said Yanamandra-Fisher. "Ground-based observations and orbiting telescopic observations, such as Hubble Space Telescope, later in December are important."
5. But wait, there's more!
Believe it or not, ISON is not the only comet! "There are several comets to enjoy right now," Battams says. He likes Comet Lovejoy (discovered by Australian amateur astronomer Terry Lovejoy), Comet Encke and Comet LINEAR.
"The bottom line is that there are several comets still visible, and even when the bright comets have gone, there will always be more. The night sky is full of wonderful things to observe, too, so people absolutely should get outside and explore the skies!" Battams said.
If you're ready to go comet-hunting, here are some websites that ISON observers say might help:
