An explosive, green comet racing toward Earth is currently zooming past the nearby Andromeda galaxy in the night sky, setting the stage for some stunning photographs. You can also watch the comet fly past our spiralling galactic neighbor in real time, thanks to an upcoming livestream.
Comet 12P/Pons Brooks (12P), also known as the devil comet, is a 10.5-mile-wide (17 kilometers) comet that circles the sun on a highly elliptical orbit every 71 years or so. 12P is a cryovolcanic, or ice volcano, comet. This means that it occasionally erupts when solar radiation cracks open its icy shell, or nucleus, allowing it to shoot out a combination of ice and gas, known as cryomagma, into space. When this happens, the cryomagma massively expands 12P's coma — the cloud of gas and dust surrounding the nucleus — making the comet appear much brighter for the next few days.
