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Water On Mars
Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere. What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae, may be grains of flowing sand and dust slipping downhill to make dark streaks.Recurring Martian Streaks: Flowing Sand, Not Water? Nasa.org 2017-11-20 The only place where water ice is visible at the surface is at the north polar ice cap. Abundant water ice is also present beneath the permanent |
Atmosphere Of Mars
The atmosphere of Mars is the layer of gases surrounding Mars. It is primarily composed of carbon dioxide (95%), molecular nitrogen (2.8%), and argon (2%). It also contains trace levels of water vapor, oxygen, carbon monoxide, hydrogen, and noble gases. The atmosphere of Mars is much thinner than Earth's. The average surface pressure is only about which is less than 1% of the Earth's value. The currently thin Martian atmosphere prohibits the existence of liquid water on the surface of Mars, but many studies suggest that the Martian atmosphere was much thicker in the past. The higher density during spring and fall is reduced by 25% during the winter when carbon dioxide partly freezes at the pole caps. The highest atmospheric density on Mars is equal to the density found above the Earth's surface and is ≈0.020 kg/m3. The atmosphere of Mars has been losing mass to space since the planet's core slowed down, and the leakage of gases still continues today. The atmosphere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valley Networks (Mars)
Valley networks are branching networks of valleys on Mars that superficially resemble terrestrial river drainage basins.Carr, M.H. (2006), The Surface of Mars. Cambridge Planetary Science Series, Cambridge University Press. They are found mainly incised into the terrain of the martian southern highlands, and are typically - though not always - of Noachian age (approximately four billion years old). The individual valleys are typically less than 5 kilometers wide, though they may extend for up to hundreds or even thousands of kilometers across the martian surface. The form, distribution, and implied evolution of the valley networks are of great importance for what they may tell us about the history of liquid water on the martian surface, and hence Mars' climate history. Some authors have argued that the properties of the networks demand that a hydrological cycle must have been active on ancient Mars,Craddock, R.A., and Howard, A.D. (2002), The case for rainfall on a warm, wet earl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outflow Channels
Outflow channels are extremely long, wide swathes of scoured ground on Mars. They extend many hundreds of kilometers in length and are typically greater than one kilometer in width. They are thought to have been carved by huge outburst floods. Crater counts indicate that most of the channels were cut since the early Hesperian, though the age of the features is variable between different regions of Mars. Some outflow channels in the Amazonis and Elysium Planitiae regions have yielded ages of only tens of million years, extremely young by the standards of Martian topographic features. The largest, Kasei Vallis, is around long, greater than wide and exceeds in depth cut into the surrounding plains. The outflow channels contrast with the Martian channel features known as " valley networks", which much more closely resemble the dendritic planform more typical of terrestrial river drainage basins. Outflow channels tend to be named after the names for Mars in various ancient world ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
