Green Comet Approaches Red Planet

Green Comet Approaches Red Planet

 On Sunday, Oct. 19th, Comet Siding Spring will pass ridiculously close to Mars--only 140,000 km away. For comparison, that's about 1/3rd the distance between Earth and the Moon. The comet was hurtling toward Mars at 120,000 mph on Oct. 11th when UK astrophotographer Damian Peach snapped this picture:

 

An international fleet of Mars orbiters and rovers will observe the encounter from close range. The most interesting data could come from MAVEN, a NASA spacecraft that has reached Mars just ahead of the comet. MAVEN is designed to study the martian atmosphere. That's good, because when the comet arrives, the atmosphere of the comet will likely brush against the atmosphere of Mars, possibly sparking auroras on the Red Planet. MAVEN could record these alien lights.

"Just as exciting," adds comet researcher Karl Battams of the Naval Research Lab, "is the prospect of the Mars Reconnaissance Orbiter's HiRISE camera being able to actually resolve (i.e. determine the shape of) the nucleus of the comet. ESA and NASA spacecraft have seen comet nuclei before, but comet Siding Spring is a little different. It's an "Oort Cloud comet" on its first ever foray into our solar system. This means it is largely pristine and will likely not have undergone any major changes since it formed. We've never seen one of these comets up close. Never. We don't know exactly what to expect."

 

From SpaceWeather.com