Astronomers are marveling at the death and apparent resurrection of a comet that dove close to the sun on Thanksgiving.
Comet ISON passed within a million miles of the sun’s surface at 1:37 p.m. Eastern time on Thursday — by which time observers had already glumly concluded that the comet had disintegrated and vaporized.
NASA posted on Twitter, “It’s likely it didn’t survive.”
ISON, which spent several billion years at the frigid edge of the solar system before starting a long journey toward the sun, had been billed as a possible “comet of the century.” Its demise seemed to be an anticlimactic ending to the story.
But “then it appears again,” said Karl Battams, an astrophysicist at the Naval Research Laboratory who has been observing the comet from Kitt Peak National Observatory in Arizona. “We see something come out.”
Images taken by spacecraft showed an increasingly bright point at the head of the comet. Dr. Battams said that current data could not offer a definitive answer, but it appeared Friday that part of ISON’s nucleus was still holding together.Continue reading the main story
“It’s definitely maybe alive,” Dr. Battams said. “There’s a strong definite chance it might be, may be alive.”
Additional observations by spacecraft and ground-based telescopes could provide a clearer picture over the next few days. The Hubble Space Telescope should be able to take a close look in a couple of weeks.
On his Twitter account, Dr. Battams mused, “So, umm ... did I mention that comets are like cats??”
Even more uncertain is whether there will be much to see in the night sky in early December, when ISON is to pass through Earth’s neighborhood. (One thing is certain, astronomers say: There is no possibility that it will strike Earth.)
The apparent resurrection raised the question: if ISON is not dead, why did it disappear during its close approach to the sun?
“At this point, we don’t have an answer to that,” said C. Alex Young, associate director for science in the heliophysics division at NASA’s Goddard Spaceflight Center in Greenbelt, Md.
The tale has gathered a wide following on the Internet, with Dr. Battams juggling media interviews and Twitter postings while also trying to digest the stream of data.
“We’ve got spotlights on us, literally,” he said in an interview, adding that he had slept only a couple of hours. “It’s a lot of pressure because at present we have a lot more questions than answers. But it’s fabulous. It’s an amazing event we’re witnessing.”
On Thursday, Dr. Battams and Dr. Young answered questions in a NASA-organized chat room on Google as ISON neared the sun.
NASA’s Solar Dynamics Observatory spacecraft sent back an image that was expected to show the comet within the corona. It showed nothing, but it was possible the comet was not close enough yet. “We thought maybe we wouldn’t see something right away,” Dr. Young said.
Half an hour later, another image came back, again with no sign of ISON.
“We didn’t see anything — nothing — and we expected we would see at least a little bit,” Dr. Young said.
A much smaller comet last year had given an impressive show, and scientists expected that even if ISON started falling apart, there would still be big pieces left for the observatory to detect.
“We were extremely let down by the lack of a show,” Dr. Young said.
But a couple of hours later, another NASA spacecraft spotted something emerging from the other side of the sun. At first it seemed to be nothing more than debris from the comet’s tail. Dr. Young left for home thinking the day had been a bust.
As he was driving, he heard his cellphone buzzing as text messages poured in. He pulled over to take a look at the data. More images were showing indications of a surviving nucleus. He headed to a diner that was closed for Thanksgiving but whose Wi-Fi network was on. “I pulled out my laptop to see what I could see,” he said.
The news that reports of ISON’s death were premature ricocheted around Twitter. Richard Branson, the British billionaire who founded the constellation of Virgin companies, posted on Friday: “Our sun melts most of comet #ISON. A little survives to fly on.”
Scientists hope that observations of ISON will also provide information about the early solar system when ISON formed.
By now, comet experts are cautious about saying what they expect to happen next.
ISON, Dr. Battams said, “is taking every opportunity to do everything we didn’t expect it to do.”Continue reading the main story