Mars got its crust quickly
Just 20 million years after the solar system formed, the Red Planet already had its outer shell
SURFACE SURVEYOR In 1997, NASA’s Sojourner rover explored the “Rock Garden,” an ancient floodplain strewn with large rocks that were swept into the valley during Mars’ wetter past. Scientists now say the Red Planet’s crust solidified much quicker than once thought.
JPL/NASA