Knowra Atmosphere of Mars Atmosphere of Mars The thin gaseous envelope surrounding Mars, composed mostly of carbon dioxide. Its low pressure and seasonal variability reflect Mars’s weak gravity, cold climate, and exchange of carbon dioxide with surface ice.
Martian atmospheric pressure : The force per unit area exerted by Mars’s atmosphere, averaging about 600 pascals at the surface. Its low value defines the atmosphere’s thinness and strongly affects liquid water and spacecraft operations.
Carbon dioxide : A colorless gas with the chemical formula CO₂, consisting of one carbon atom bonded to two oxygen atoms. It makes up about 95 percent of Mars’s atmosphere.
Noachian : The earliest major geological era of Mars, extending from its formation to roughly 3.7 billion years ago. Mars likely had a thicker, warmer atmosphere during parts of this early era.
Mars entry, descent, and landing : The sequence by which a spacecraft slows, descends, and reaches the Martian surface. The thin atmosphere provides limited braking, making landing systems difficult to design.
Earth's atmosphere : The layer of gases surrounding Earth, dominated by nitrogen and oxygen and sustained by gravity and geological and biological cycles. Earth’s denser, nitrogen-rich atmosphere provides a sharp comparison with Mars’s low-pressure carbon dioxide air.
Martian dust storm : A weather event in which winds lift dust into the Martian atmosphere, sometimes spreading it planetwide. Suspended dust absorbs sunlight and changes atmospheric temperatures and circulation.
Argon : A chemically inert noble gas with atomic number 18. It is the second most abundant gas in Mars’s atmosphere.
Jezero crater : A 45-kilometer-wide impact crater on Mars that contains an ancient river delta and lake deposits. Its rocks preserve evidence of past surface water under a different atmospheric climate.
Mars helicopter Ingenuity : A small robotic helicopter that completed powered flights in Mars’s thin atmosphere. Its rotor design had to compensate for the low density of Martian air.
Venus's atmosphere : The dense atmosphere surrounding Venus, composed mostly of carbon dioxide and associated with extreme surface temperatures and pressure. Venus shows how a carbon dioxide atmosphere can differ radically under stronger heating and greater atmospheric mass.
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