The Bad Astronomer's gallery of comet pictures
From Phil Plait's page at Salon: Gallery: The Red Planet and the Comet:
Yesterday, Oct. 19, at approximately 18:30 UTC, Mars got buzzed by a comet.
The comet, named C/2013 A1 (Siding Spring), passed just 130,000 kilometers (80,000 miles) above the surface of Mars, the closest cometary encounter with a terrestrial planet ever seen. (The adjective is because
Jupiter has been hit by several comets and asteroids in the past few years.)
Siding Spring is an
Oort cloud comet, meaning it came from the very remotest regions of the solar system, almost certainly plunging into the inner system for the first time after billions of years in the dark. It chose quite a path for its first trip here! Mind you, the comet got three times closer to Mars than the Moon is to Earth. This was a close shave indeed.
NASA and other space agencies took precautions, moving their orbiting probes to the far side of the Red Planet during closest approach while the rovers were pretty much on their own. Happily, they all appear to be fine, even after the comet dropped tons of material into the atmosphere at dozens of kilometers per second.
Were still awaiting images taken from those probes, but in the meantime, quite a few dramatic pictures were taken from Earth. Here are a few of the ones I like best
and if you want to learn more about comets, may I humbly suggest my own
Ten Things You Dont Know About Comets page when youre done perusing these images?
The images from this article are a bit big to post here; you'll have to see Phil's post for them in their awesomeness!