Using a camera on its arm, the Curiosity rover took a break from its Mars excursion to snap a self-portrait.
Maggie Koerth-Baker documents the picture and explores how time passes on Earth versus how it passes on Mars, for Boing Boing. She explains that the Martian equivalent to an Earth day is a “Sol,” and is titled so because a day on Mars is slightly longer:
“What really stuck out to me, though, was the use of ‘Sol 32’. Sol is what you call a ‘day’ on Mars. We use a different word because the length of time is also a bit different. One Martian Sol is equal to 24 hours, 39 minutes, and 35.244 seconds. Sol 32 isn’t, itself, a date, but simply a record tracking the number of sols that Curiosity has been on Mars—starting with Sol 0, which was August 6th. Every mission to Mars since Viking has kept its own sol count, so you can’t really use these sol dates to keep track of history except as it relates to a specific mission.”