CAPE CANAVERAL, Fla. (AP)—For months, all eyes in the sky have pointed at the comet that’s zooming toward a blisteringly close encounter with the sun.
The moment of truth comes Thursday—Thanksgiving Day.
The sun-grazing Comet ISON, now thought to be less than a mile wide, will either fry and shatter, victim of the sun’s incredible power, or endure and quite possibly put on one fabulous celestial show.
Talk about an astronomical cliffhanger.
Even the smartest scientists are reluctant to lay odds.
Should it survive, ISON, pronounced EYE’-sahn, would be visible with the naked eye through December, at least from the Northern Hemisphere. Discernible at times in November with ordinary binoculars and occasionally even just the naked eye, it already has dazzled observers and is considered the most scrutinized comet ever by NASA. But the best is, potentially, yet to come.
The closer the comet gets to the sun, the faster it gets.
In January, it was clocked at 40,000 mph.
By last Thursday, with just a week to go, it had accelerated to 150,000 mph.
Right around the time many Americans will be feasting on turkey, the comet will zip within 730,000 miles of the sun, less than the actual solar diameter. In other words, another sun wouldn’t fit in the missed distance.
By the time ISON slingshots around the sun, it will be moving at a mind-boggling 828,000 mph.
Whether it survives or is torn apart, earthlings have nothing to fear.
The comet will venture no closer to us than about 40 million miles, less than half the distance between Earth and the sun. That closest approach to Earth will occur Dec. 26. Then it will head away in the opposite direction forever, given its anticipated trajectory once it flies by the sun.
The newly launched Maven spacecraft en route to Mars will gaze at ISON the second week of December, once its ultraviolet instrument is up and running.
"That’s well after closest approach to the sun," the University of Colorado’s Nick Schneider, who’s in charge of the instrument, said in an email. So it’s not known "whether we’ll see a comet, comet bits or the last wisps of comet vapor."
"Whatever happens, it’s bound to be interesting. The quip from my colleagues is, ‘Comets are like cats: They have tails and do whatever they want.’"
Some sky gazers speculated early on that ISON might become the comet of the century because of its brightness, although expectations have dimmed over the past year.
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