Fear and Dread

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The European Space Agency’s Mars Express has captured footage of Mars’ two tiny moons, Phobos and Deimos, passing each other in what is known as a “mutual event”. Although the moons themselves are in no special positions the images are noteworthy, being the first time the moons have been photographed passing each other.

Mars Express’ High Resolution Stereo Camera (HRSC) took 130 images of the moons on November 5 over a time period of 1.5 minutes. The images were then combined to make this animation.

The moons are separated by a distance of 8,948 miles in these images.

14-mile-wide Phobos is named after the Greek word for fear, 8-mile-wide Deimos is named after the word for dread. Small and irregularly-shaped, they are most likely captured asteroids. Both were discovered in 1877 by American astronomer Asaph Hall.

Read more about these images on the ESA site or on The Planetary Society’s blog.

Credit: ESA / DLR / FU Berlin (G. Neukum)