5 ms·

wait what?

• simonh 7y ago
  All the other inner planets and asteroids are dry, but Earth is wet, so it’s always been a bit of a mystery where the water came from.
  • encoderer 7y ago
    Where did the water on Mars come from? Any correlation?
    • simonh 7y ago
      Mars, as far as we can tell, has very little water compared to Earth, even back when it appears to have had liquid water on the surface. It's a bit further out, so we'd expect it to have more water compared to the rest of the inner planets. It seems to be consistent with occasional deliveries of water from collisions with comets. In comparison, Earth has vastly more water.