Talk:Atmosphere of Mars

Wiki Education assignment: SPAC 5413 - Planetary Geology

This article was the subject of a Wiki Education Foundation-supported course assignment, between 17 January 2023 and 13 May 2023. Further details are available on the course page. Student editor(s): Alec Fitting (article contribs).

— Assignment last updated by Alec Fitting (talk) 17:24, 9 May 2023 (UTC)

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The atmosphere of Mars is a layer of gases surrounding Mars, which is composed primarily of carbon dioxide (95%), along with molecular nitrogen (2.8%), and argon (2%) and trace levels of other compounds. The Martian atmosphere is much thinner than Earth's, its average surface pressure of 610 pascals (0.088 psi) being less than 1% of the Earth's value. This 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 effective temperature at the surface is around 210 K (−63 °C; −82 °F), and it has a large daily temperature range due to the low thermal inertia; in some regions it can vary from −75 °C (−103 °F) to near 0 °C (32 °F). Dust devils and dust storms are prevalent on Mars, which are sometimes observable by telescopes from Earth, and can threaten the operation of Mars rovers. Planet-encircling dust storms occur on average every 5.5 Earth years (3 Martian years), but the mechanism responsible for these storms is not well understood. This small dust devil was captured by NASA's Curiosity rover in 2020.

Animation credit: NASA / JPL-Caltech / Space Studies Institute

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carbon dioxide vs water

i took out a sentence saying water vapor would make Mars warmer, and t hen self-reverted. CO2 is much more powerful than water vapor, and at global warming potential we say water may even be negative. but it seems the relationship isnt proportional to total amt in atmosphere, so i self-reverted. i will try to look into this if i get a chance.—Soap— 23:05, 2 August 2023 (UTC)

Calculation about greenhouse effect on Mars is wrong!

It says at the beginning of the article that "The average surface pressure (on Mars) is about 610 pascals (0.088 psi) which is 0.6% of the Earth's value.". But further below the article claims that "Although Mars's atmosphere consists primarily of carbon dioxide, the greenhouse effect in the Martian atmosphere is much weaker than Earth's: 5 °C (9.0 °F) on Mars, versus 33 °C (59 °F) on Earth due to the much lower density of carbon dioxide, leading to less greenhouse warming." That cannot be. The amount of carbondioxide in the Earth's atmosphere is 0.04%. When the density of Mars' atmosphere is 0.6% of the earth's value but it consists to 95% of carbondioxide then the density of carbondioxide would be equal to ~0.55% in the Earth's atmosphere. So the carbondioxide density on Mars is much higher than on earth, it is 0.55% in compare to the Earth's 0.04%, however thin the atmosphere might be. Thus, if carbondioxide would indeed be the only gas to cause greenhouse effects then Mars should have a much stronger such effect than Earth has. The truth is that ALL gases casue greenhouse effects, nitrogene and oxygen have even higher heat factors than carbondioxide and capture heat and keep it (the greenhouse effect) and that gives earth a much stronger greenhouse effect. It is the atmospheric density which is relevant, not the composition. Helge Tietz (talk) 22:47, 6 July 2025 (UTC)

No, nitrogen and oxygen have comparably negligible greenhouse potentials. Water, however, does--and it's very strong. It's actually the strongest contributor to the Earth's greenhouse effect, not CO2 (so the article still needs correction). The reason why CO2 is still important (and why it's so relevant to climate change, natural and anthropogenic) is because the amount of water in the Earth's atmosphere is still dependent on CO2. Remove CO2, and the Earth cools and its atmosphere becomes drier, and vice versa. ArkHyena (they/any) 23:18, 6 July 2025 (UTC)