Reviewing 2013: Comet ISON

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Oh Comet ISON, what the heck happened?

In September 2012, Comet ISON was discovered by Russian astronomers and it was quickly revered as the “Comet of the Century.” It was a virgin comet, fresh from the Oort Cloud, and it was destined to barrel past the sun to become one of the brightest objects in the sky. The world rallied behind the comet. Daily comet health updates read like war reports. The media cheered ISON on. As it got closer and closer to the sun everything was looking good! The comet was holding it together! It was going to make it! Until… it didn’t. The Thanksgiving Day roast proved to be too much for this famous comet. Although there were signs that ISON’s nucleus survived the encounter, the sun’s extreme heat and tidal shear likely ripped it to shreds. This cosmic story may not have had a a happy ending, but ISON was no turkey; it was mainstream news for months, proving that mankind’s fascination with astronomy is alive and well.

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Sad news, comet fans: ISON is no more. It’s a vaporized husk of its former self. A sublimated dirty snowball. Comet ISON is an ex-comet and this time it’s not playing.

This sad turn of events is brought to you by the joint NASA/ESA Solar and Heliospheric Observatory (SoHO)’s LASCO instrument that gives a wide-angle view of the sun’s atmosphere (pictured above). For the duration of Comet ISON’s close approach to our nearest star, LASCO has been carefully tracking the comet’s progress. After many heart-stopping hours post-perihelion on Nov. 28, space experts nearly gave up hope — ISON had vanished from LASCO’s view, apparently not surviving the sun’s extreme tidal forces and powerful radiation.

But then, just as the U.S. was recovering from Thanksgiving turkey and wine, ISON re-energized; a component of its roasted nucleus had survived the turmoil and was brightening.

ANALYSIS: All Eyes on ISON as ‘Phoenix’ Comet Rises from Ashes

Unfortunately, the brightening was short-lived. Despite a couple of days of hope, Comet ISON’s nucleus has all but disappeared, leaving a ghostly wisp of dust behind.

The “Comet of the Century” is now, officially, the Turkey of the Century.

“Among experts, a consensus is building that the comet broke apart shortly before perihelion (closest approach to the sun),” writes Tony Phillips, NASA astronomer and curator of Spaceweather.com.

ANALYSIS: Comet ISON Barely Survives Thanksgiving Solar Roast

Like the countless sungrazing comets that have come before it, ISON succumbed to the close solar pass. Although hopes were high that the comet would survive the plunge, no one really knew what ISON was going to do. As a “virgin” comet from the Oort Cloud (a hypothetical cloud of cometary objects approximately one light-year from the sun), this was ISON’s first visit to the inner solar system. With little information on the comet’s composition, cometary fragmentation was always a possibility.

All that remains of Comet ISON seems to be a fan-shaped debris field of small fragments of the once-mighty cometary nucleus, each shard frantically venting the remaining ices into space. Any hope of seeing a dazzling naked-eye comet just in time for Christmas is vaporizing faster than the sublimating ISON fragments that now litter interplanetary space.

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