It appears there will be no once-in-a-lifetime celestial light show this month asstreaks past Earth trailed by a glorious tail of ice, water, rock, and dust.
On Monday, one of the leading ISON watchers, Karl Battams of the U.S. Navy's Sungrazer Comets citizen science project and the NASA-sponsored comet ISON observing campaign, posted a eulogy for ISON, which is now believed to have disintegrated into millions of fragments as it swung around the sun, coming within a million miles of the star's surface.
"Tragically, on November 28, 2013, ISON's tenacious ambition outweighed its ability, and our shining green candle in the solar wind began to burn out," Battams writes (NASA itself has since issued a statement saying that it continues to investigate ISON's fate, but calls it "likely" that ISON is now "only dust").
Last Thursday, as many Americans feasted with their families for Thanksgiving, Comet ISON reached perihelion -- its closest point to the sun before swinging around the star to pass us again on its way out of the solar system.
What followed was a confusing roller-coaster of uncertainty as to the fate of the comet. For hours there was no sign of ISON on images returned by solar observatories, leading some to jump to the conclusion that the space rock had been essentially vaporized by the heat of the sun.
Then NASA observations began to show something emerging from the other side of the sun that appeared to be a comet with at least a small surviving nucleus. It now appears that what we were seeing was the fragmentedthat will likely begin to rapidly fade away from view.
ISON was a big comet on its virgin trip through our solar system that first became visible toearlier this fall, and was believed to hold the potential to become one of the most spectacular such visitors in decades, if not centuries, but only if it could survive its close encounter with the sun.
But don't despair, fellow super space nerds, such a historic event could still be in our future. As Battams points out, ISON was undiscovered until a little over a year ago and is "survived by approximately several trillion siblings."
Updated at 12:05 p.m. with a statement from NASA.