Inside Mars, a 'rocky road' mantle reveals a violent past

Breakthroughs, discoveries, and DIY tips sent every weekday. Don't let the appetizing description fool you. When planetary scientists say the interior of Mars resembles a rocky road brownie more than a piece of buttery shortbread, the tasty metaphor masks billions of years of geological violence. In a re-examination of previous observations collected by NASA's decommissioned InSight probe, researchers have discovered that the Martian mantle is embedded with ancient fragments measuring as much as 2.5 miles wide. The data is detailed in a study published on August 28 in Nature.