1. 1 There’s lots of evidence for water on Mars…in the past River beds and teardrop-shaped “perched” craters. Lake beds Minerals have been found that only form under water. Outflow Channels Sedimentary layers in the walls of the Valles Marineris and many craters. Gusev Crater! 88

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5. 5 This is the shore of an ancient lake. Notice the layering in the rocks! 92

6. 6 These little nodules, “blueberries”, are made of the mineral hematite that usually forms only under water. The blueberries were found near Meridiani Planum, the landing site of NASA’s Mars Exploration Rover Opportunity. Image credit: NASA 93

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8. 8 Similar hematite nodules here on earth. 95

9. 9 Obvious layering in the rocks near the landing site of NASA’s Opportunity Rover. Image Credit: NASA 96

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11. 11 Finally…Gusev Crater In 2004, NASA’s rover Spirit landed inside Gusev Crater. This crater quickly showed that it had once been full of water. It’s connected by a valley to an outflow channel, and was probably filled with water and sediment during the catastrophic flooding. 98

12. 12 What about recent water on Mars? There is some possible evidence for recent water on Mars: –Gullies in the walls of some craters might have been formed when water ran down the crater walls under layers of frost or ice. Credit: Malin Space Science Systems, MGS, JPL, NASAMalin Space Science SystemsMGSJPLNASA 99

13. 13 Newton Basin 100

14. 14 Where Did the Water Go? Today, liquid water can’t exist long on the surface of Mars due to the low temperature and low atmospheric pressure. Loss of magnetic field... atmospheric erosion … water lost to space. Some water is still in the polar ice caps and may still exist in permafrost. 101