Bright new deposits seen in NASA images of two gullies on Mars suggest liquid water carried sediment in the past seven years. Liquid water is considered necessary for life, so these new findings heighten intrigue about possible microbial life on Mars. These findings were provided by NASA's Mars Global Surveyor.
The atmosphere on Mars is so thin that liquid water cannot persist at the surface. However, researchers propose that water could remain liquid long enough, after breaking out from an underground source, to carry debris before totally evaporating and freezing.
The Global Surveyor team also assessed the rate at which new impact craters appear on Mars.