Astronomy for all
Tuesday April 6th 2010

Phobos, our closest look

Phobos is the larger of the two moons orbiting Mars. Both Phobos and Deimos appear very similar to asteroids, however capturing 2  asteroids, circularizing their orbits, and dragging them into Mars’ equatorial plane seems unlikely. Here is Phobos as it appeared during last week’s flyby of ESA’s Mars Express. You can clearly see in great detail just how irregular Phobos really is, with strangely dark terrain, numerous unusual grooves, and a spectacular chain of craters crossing the image center. Phobos is only about 25 kilometers in length and does not have enough gravity to compress it into a ball. Phobos orbits so close to Mars that sometime in the next 20 million years, tidal deceleration will break up the rubble moon into a ring whose pieces will slowly spiral down and crash onto the red planet. The next planned mission to Phobos is the Russian mission Phobos-Grunt which is scheduled to launch and land on Phobos next year.

Phobos from Mars Express Credit: G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA

Leave a Reply