Water on Mars
availability of water on Mars / From Wikipedia, the free encyclopedia
There is less water on Mars compared to Earth. Most of the water known is in the cryosphere (permafrost and polar caps). There is no liquid water. There is only a small amount of water vapor in the thin atmosphere.[1]
The conditions on the planet's surface do not support the long-term existence of liquid water. The average atmospheric pressure and temperature are far too low, which freezes water. However, it seems Mars once had liquid water flowing on the surface.[2][3] This would make large areas like Earth's oceans.[4][5][6][7]
There are a number of signs of water on or under the surface, now or in the distant past.[8] These include stream beds, polar caps, spectroscopic measurement, eroded craters. Also, there are minerals which are often formed when there is liquid water (such as goethite), grey, crystalline hematite, phyllosilicates, opal, and sulfate.[9][10][11][12][13]
The Mars flybys such as Viking, Mars Odyssey, Mars Global Surveyor, Mars Express, and the Mars Reconnaissance Orbiter had cameras. They took pictures of what seem to be ancient lakes, ancient river valleys, and widespread glaciation.[14][15][16][17][18] An orbiting Gamma Ray Spectrometer found ice just under the surface of much of the planet. Also, radar studies found ice that were thought to be glaciers. The Phoenix lander showed ice on Mars when it was landing. Phoenix also showed ice melting, snow falling, and even saw drops of liquid water.[19][20][21]
A recent report says Martian dark streaks on the surface were affected by water.[22]