NASA Science Briefing: Comet Siding Spring at Mars

Five months after landing in Jezero Crater, the Perseverance Mars rover is finally ready to begin collecting samples for eventual return to Earth.

Where did the two natural satellites of Mars, Phobos and Deimos, come from? For a long time, their shape suggested that they were captured asteroids. However, the shape and course of their orbits contradict this hypothesis. Two independent and complementary studies now provide an answer: these satellites formed from the debris of a gigantic collision between Mars and a protoplanet one-third its size.

The red planet Mars is destined to become the ringed planet within 40 million years’ time, when its largest moon Phobos is torn apart, according to two scientists from the University of California, Berkeley.