How did Mars Moon Phobos Become so Groovy?

Billions of years ago, Mars suffered from numerous big impacts, and the resulting backwash ultimately scarred the surface of Phobos, one of the Red Planet's two tiny moons.

Published On 05/27/2014
11:59 AM EDT
The dark surface of Mars' moon phobos was captured in this photo by the European Mars Express orbiter in 2010. | G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA; Acknowledgement: Peter Masek