A moon in the Martian sky

The moon Phobos as photographed in the Martian sky by Curiosity on sol 45. It is faintly visible to the upper right.
Credit: NASA / JPL-Caltech

While most of Curiosity’s attention is of course on the surrounding terrain, as it traverses across the remains of an ancient streambed, it does sometimes look up at the sky as well. The Spirit and Opportunity rovers have also done so, photographing water-ice clouds overhead (as in the header image for this blog) and even occasional transits of the two tiny Martian moons Phobos and Deimos in front of the Sun.

Cropped and enhanced version of the image showing more detail on the moon Phobos. Credit: NASA / JPL-Caltech

Curiosity also recently watched Phobos partially cross in front of the Sun, but now has one-upped that, taking the first daytime photograph of a Martian moon (Phobos again) as it normally looks in the sky, on sol 45 (September 21, 2012). You have to look carefully at the first image, but Phobos is there, appearing almost the same as a crescent moon in Earth’s sky, except that the shape is more irregular (Phobos is potato-shaped). In the second cropped and enhanced imaged, a few more details are visible.

This is the first time such a photograph has been taken of an alien moon in an alien sky; a reminder of how Mars is both similar to, and different from, the Earth. Hopefully sometime in the relatively near future, astronauts will be able to stand on Mars’ surface and see this view for themselves…