Curiosity Rover Captures Martian Eclipse

NASA's Curiosity rover snapped an elegant sequence of images showing Mars' moon, Phobos, passing in front of the sun on Sept. 13. Because the tiny moon moves so fast through the Martian sky, the alien eclipse lasted only a few seconds.

The images were taken with Curiosity's MastCams, which were positioned to watch Phobos zoom in front of the sun.

In contrast to its blazing glory in Earth's daytime skies, the sun is a tiny dime-sized circle as seen from Mars. Phobos is even smaller and can never completely engulf the sun, merely taking a nibble in this animation. Our moon, on the other hand, happens to be just the right size and distance away from Earth that when it passes in front of the sun, it completely blocks out its light.

Phobos is really more of an asteroid than a moon — the small potato-shaped object is only 16 miles across at its widest. Because it travels around Mars in a speedy 7.6 hours, it has a high probability of aligning with the sun, and eclipses like this happen somewhere on Mars almost any day of the year. Most landers on Mars have captured at least one Phobos transit. From space, satellites have captured images of Phobos' shadow racing across the Martian surface.

Mars' other moon, Deimos, is farther from the planet and obscures even less of the sun when it eclipses.

Images: NASA/JPL-Caltech/Malin Space Science Systems/Wired Science

Adam is a Wired reporter and freelance journalist. He lives in Oakland, Ca near a lake and enjoys space, physics, and other sciency things.

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