Here’s a beautiful wallpaper of the Comet ISON. It began its journey from the Oort cloud at least a million years ago, a swath of icy objects that orbit far beyond Neptune. This is its first trip through the inner solar system. As of today it is unclear whether the comet will survive its trip around the sun.
In any case, it makes for a glorious thing to see shooting across the sky on Thanksgiving! More details from NASA here: http://rtna.me/1b2imWc