Wow, now isn’t that the coolest! The STEREO-B spacecraft took this photo of Comet C/2011 L4 PANSTARRS and two planets to boot on March 10. NASA’s dual STEREO sun-watching observatories are positioned in Earth’s orbit, one ahead of the planet and one behind. From these two locations they’re able to monitor both the front and backsides of the sun, something otherwise impossible to do from the ground. Their eyes also see background stars down to 13th magnitude, planets and the occasional comet like PANSTARRS.
Look closely at the comet. Uncompromised by Earth’s atmosphere, we can see four tails.One of the two short spikes is electrified carbon monoxide gas carried away by the solar wind. The other might be made of iron atoms from the iron-sulfur mineral troilite (common in meteorites) blown back by sunlight itself. Two additional tails glow by sunlight reflecting off dust particles released from the comet’s ices as they’re vaporized by the heat of the sun.
Click HERE for maps to help you find Comet PANSTARRS – from Earth – tonight.