Earth, Mars and Venus all looked pretty similar when they first formed. Today, Mars is dry, cold, and dusty; Venus has a hot, crushing atmosphere. Why did these sibling planets turn out so different?

Scientists are thrilled with the tiny asphalt-black rocks, and most of the sample hasn't even been revealed yet.

Since touching down in Jezero Crater, NASA's Perseverance rover has already cached 6 samples that could one day be brought back to Earth. Astrobiologists hope they hold signs of past microbial life.