SpaceWeather.com reports that amateur astronomers have observed a “comet explosion”:

Almost 450 million km from Earth, Comet C/2012 X1 (LINEAR) has exploded. Amateur astronomers are reporting a 100-fold increase in the comet’s brightness compared to predictions, and the comet’s atmosphere or “coma” now resembles that of exploding Comet 17P/Holmes in 2007. Using a remotely-controlled 0.5 meter telescope in New Mexico, European observers Ernesto Guido, Martino Nicolini and Nick Howes took this picture of the spherical explosion on Oct 21st:

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Image from Ernesto Guido, Nick Howes and Martino Nicolini

“The predicted magnitude of the comet on Oct. 20th was about +14,” says Guido. “Now it is close to +8.5.” This is below the threshold for naked-eye visibility, but bright enough for backyard telescopes equipped with digital cameras.

The comet may not have literally exploded but instead a vein of water ice or other volatile material may have become exposed and erupted, creating a cloud of material around the object.

Here is a video showing images of the comet:

>http://youtu.be/95wvUxUQqxo