Odd Couple: Phobos and Jupiter

I'm hard-pressed to imagine two solar-system bodies more dissimilar than Phobos, the larger of Mars's sooty little moons, and giant Jupiter, the resplendent king of planets.

Phobos and Jupiter
On June 1, 2011, the little moon Phobos loomed large as it passed in front of distant Jupiter. The scene was captured by the High Resolution Stereo Camera aboard the Mars Express orbiter.
ESA / DLR / G. Neukum
Yet earlier this month these two made a joint appearance of sorts, when both were simultaneously viewed by the European Space Agency's Mars Express orbiter.

The craft's High Resolution Stereo Camera snapped 104 frames over 68 seconds as Phobos, looming large because it was 46,000 times closer, scooted across the field and clipped the disk of Jupiter. At the time the little moon was 7,077 miles (11,389 km) from the camera and Jupiter was 329 million miles (529 million km) distant.

You can see the entire video here, along with more details about this recent encounter — or just download and view the high-resolution video. If you have a pair of anaglyphic (red-blue) glasses, check out the 3-D composite frame here.

Just 11 miles (18 km) wide and half again as long, Phobos has a single dominant crater (Stickney), which appears in profile at the lower-left edge of the moon's irregular disk.

Although you don't hear about Mars Express much, this highly capable spacecraft has been studying the Red Planet since late 2003. Its eight instruments record the planet and its atmosphere from a looping polar orbit.

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