Put yourself in Curiosity's wheels for a moment. You're 99 million miles from where you were born. You can never go back. The only other creatures like you are somewhere else on a big planet, and you're unlikely to ever meet. You're doing amazing things for science and you're adored by millions. Still, you might want to take a picture of home for posterity.
That's just what Curiosity did, snapping its first picture of Earth and the moon from the surface of Mars. Though the two heavenly bodies are just pinpoints of light, they are still much brighter than any star seen through the Martian twilight.
The photo makes for a very spare composition. It almost looks like it could have been taken on Earth, with just a jagged black horizon line to show the surface of Mars. The image was captured 80 minutes after sunset on January 31, which represents the rover's 529th Martian day.
We're used to seeing closer-up photos of Earth from space, but the Curiosity pic is a reminder of just how far away Mars is from our blue marble. The rover is a long way from home. If we ever succeed in sending humans to Mars, this is the view they will get when they look back to where they came from.