That's Spirit, my SUV on my adopted planet, Mars.  It's a digital picture sent to Earth via telemetry through the NASA Mars Orbiter, and yes, it's public domain if you live on Earth or Mars.  If you are from anywhere else, please consult your local legal authorities.

Over my left shoulder is a fine photograph of what few others have seen: a sunset on Mars.  I had to give much thought whether to use this as my avatar here on OS, but decided on Spirit, because the sun powers my SUV on Mars, so it sort of is in the picture anyway.  But if you choose to use it: Courtesy again of the NASA Mars Orbiter and the Spirit SUV:

 Spirit is a solar powered SUV, so it's a green machine.  It isn't easy being green, especially on the Red Planet. 

I love to observe at a distance.  If I were in the midst of all that is happening down there, the family might decrement by one its membership due to a sudden airing out of the cerebrum via high-velocity projectiles.  And that, my OS friends, is messy.  Far better to watch from, ahem, afar.