Here's another astonishing photo made by a satellite in outer space. This shot of the deep Candor Chasma valley on Mars was taken by a camera aboard Nasa's Mars Reconnaissance Orbiter. Scientists say the photo is important because it shows areas or rock where water could have flowed. They can say what they want, but I think what really intrigues them about the image is just how beautiful it is. And that raises some interest questions about the nature of photography.