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How does atmospheric pressure on Mars compare with atmospheric pressure on Earth?
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Mars
An especially serene view of Mars (Tharsis side), a composite of images taken by the Mars Global Surveyor spacecraft in April 1999. The northern polar cap and encircling dark dune field of Vastitas Borealis are visible at the top of the globe. White water-ice clouds surround the most prominent volcanic peaks, including Olympus Mons near the western limb, Alba Patera to its northeast, and the line of Tharsis volcanoes to the southeast. East of the Tharsis rise can be seen the enormous near-equatorial gash that marks the canyon system Valles Marineris.
The atmosphere of Mars is extremely thin compared to that of Earth. At the Martian surface, the atmospheric pressure is less than 1 percent of the atmospheric pressure found on Earth.1
Several factors contribute to the nature of this pressure:
- Topographical Variation: Because of significant altitude differences across the Martian landscape, surface pressures can vary by a factor of 15 depending on the location.1
- Seasonal Fluctuations: Unlike Earth, Mars experiences large annual pressure changesāup to 26 percentāas carbon dioxide, which makes up the vast majority of the atmosphere, freezes into the polar caps during winter and sublimes back into a gas during the spring.1
- Historical Loss: While Mars once possessed a much thicker atmosphere, much of its original inventory of volatile substances was lost to space over time due to the solar wind and ultraviolet radiation from the Sun.2