Star-gazers could be in for quite the show in 2013. Two Russian astronomers, Vitali Nevski and Artyon Novichonok discovered an object that is causing quite a stir. The duo found the object using telescopes that are part of the International Scientific Optical Network (Ison), a world-wide sky survey that scans the skies for comets and asteroids. The comet, a ball of rock and ice the size of a mountain, has been dubbed Comet Ison, and some are already dubbing it "the comet of the century".
Why all the hubbub over what amounts to a dirty snow ball? Comet Ison is believed to have originated from the Oort Cloud, a shell of comets and dust that surrounds our solar system about of quarter of the way between the Sun and its nearest stellar neighbor, Proxima Centauri, a distance of roughly a light-year. From that distance, the sun is little more than a dull point of light, only slightly brighter than the starry backdrop. Despite the distance, the Sun's gravity is enough to keep Oort Cloud objects in orbit. On occasion, a passing body or a hitherto unknown star or planet disturbs the balance and causes a comet to fall inward, toward the solar system.
But none of that explains what makes Ison unique. The comet's orbit will take it within about two million miles of Sol. This is closer even than the planet Mercury, whose orbital distance of about forty-three million miles does not save it from having surface temperatures hot enough to melt lead on its day-light side. This close orbital pass is what could lead to one of the greatest night time light shows of 2013. The comet could be as bright as the full moon. Brighter, even. Or not. There is always a chance that Ison could simply vaporize in the intense heat so close to the Sun. Or it could be that Ison may not have enough ice within it to produce the expected bright coma and tail. Whether Ison is a spectacle, or a spectacular flop, only time will tell.
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