杏吧原创

You can鈥檛 keep a good comet down. After a nail-biting night in which comet ISON disappeared into the sun and then initially failed to re-emerge 鈥� prompting premature declarations of its demise 鈥� the most famous comet of recent times is now back.

What remains of the teasing, icy fuzzball is unlikely to provide us with the spectacular lightshow that once looked possible. But ISON looks set to remain a source of bafflement and scientific data 鈥� 鈥� for the days and weeks to come.

鈥淭his ridiculous, crazy, dynamic and unpredictable object continues to amaze, astound and confuse us to no end,鈥� writes in Washington DC, on the Comet ISON Observing Campaign blog.

He even dubbed it 鈥淪chr枚dinger鈥檚 comet鈥� because of its apparent ability to be both dead and alive like the hypothetical quantum cat .

Dirty snowball

A host of solar observatories watched the sun-dive last night and initial images looked like bad news as the comet seemed to have been obliterated. The European Space Agency : 鈥淐omet #IISON is gone, thanks for sharing this comet-watching night with us.鈥� New 杏吧原创 .

But the latest pictures tell a different story. A bright object has remerged along ISON鈥檚 predicted trajectory, suggesting at least some of it survived. 鈥淥ver night it looks like quite a significant proportion of the large particles that were in the comet before it reached the sun have made it through,鈥� says of University College London.

The 鈥渄irty snowball鈥� of ice and dust that makes up ISON will have shrunk significantly from its original 2-kilometre size. 鈥淚f it has survived, it鈥檚 a much smaller nucleus than what existed just a few days ago,鈥� says Jones.

ISON鈥檚 strange re-brightening has left astronomers baffled. One explanation is that ISON had the life squeezed out of it by the sun鈥檚 immense gravity and is now gasping for breath. 鈥淲hat might have happened is the nucleus had already fragmented a couple of days ago, but it still looked like one nucleus going in,鈥� says Jones.

These fragments would have individually sped up and spread out as they whipped around the sun, which would have reduced their collective brightness. 鈥淭hen after going past the sun they鈥檙e starting to bunch up again, so it鈥檚 looking brighter.鈥�

Massive opportunity

Unfortunately, if this theory is correct, it means you probably won鈥檛 be able to spot ISON in the dawn sky over the next few weeks as had originally been hoped 鈥� at the very least you鈥檒l need a pair of binoculars. 鈥淭he chances of it being an impressive comet viewed from the ground are looking dim now, but I鈥檇 love to be proven wrong,鈥� says Jones.

Astronomers still have a busy period of observations ahead of them, however, as ISON鈥檚 ordeal is a massive scientific opportunity. 鈥淲e were hoping to get more out of it if it had survived, but the fact that it has broken up now is telling us answers to different questions,鈥� says Jones.

ISON has from the Oort cloud, a collection of distant objects containing material frozen as the solar system was formed. The comet has now released this material, giving researchers a glimpse into the distant past. 鈥淲e鈥檝e got a bonanza of data and we鈥檙e looking forward to analysing it,鈥� says Jones.