It was to be the comet of the century, or at least the comet of the century so far.
But as ISON made its much anticipated solar rendezvous on Thanksgiving day, something happened to it on the far side of the Sun. Initially, astronomers said the comet failed to reappear as it circled the Sun, but by Friday morning they reversed themselves and said ISON did survive, but in a greatly diminished state. The comet got beat up pretty bad as it grazed the sun, the heat vaporizing ISON’s ice and gas, and it’s rocky core likely began to boil.
But at least part of it did survive and reappeared as it came out from behind the Sun, much fainter, perhaps broken, but visible again – at least for the time being.
“We have a whole new set of unknowns, and this ridiculous, crazy, dynamic and unpredictable object continues to amaze, astound and confuse us to no end.”
Karl Battams, a comet scientist for the Naval Research Laboratory, said in an online chat from the Kitt Peak Observatory in Arizona Thursday, “At this point, I do suspect that the comet has broken up and died.” But ISON has surprised astronomers before, and it confounded them further when a close look found that the comet had reappeared, perhaps not quite intact, but with a tail that was growing again.
In a blog later Thursday night, Battams wrote: “We have a whole new set of unknowns, and this ridiculous, crazy, dynamic and unpredictable object continues to amaze, astound and confuse us to no end. We ask that you please be patient with us for a couple of days as we analyze the data and try to work out what is happening.”
There is a reason comets fascinate us. Humans have noted their passing for millennia, yet we still don’t fully understand them. They twist and turn through the Solar System, sometimes putting on a great show, then disappear for decades or centuries before returning right on schedule – or not.
We often talk how comets and asteroids could be devastating if one were to hit the fragile Earth, but what they’re most likely to run into are the objets in the Solar System with the deepest greatest gravity wells such as the gas giants Jupiter and Saturn, and the Sun itself, melting and tearing apart the comet before it can escape the star’s clutches.
Battered ISON is made of sternrt stuff than many sun-grazing comets, but whether it will yet put on a great nighttime show to claim the mantle of the comet of the century, or will only show a wisp of a tail goodbye as it fades and disintegrates, we won’t know yet for a few more days.
Even if we can’t see it with the naked eye, astronomers at least are seeing it put on a great show for them.