Related topics: nasa · mars · red planet

Dust storms on Mars

Dust is a critical component in the Martian atmosphere. It influences the atmosphere's circulation by heating or cooling it and is in turn redistributed around the planet by atmospheric winds. In this dust cycle, dust storms ...

New water cycle on Mars discovered

Approximately every two Earth years, when it is summer on the southern hemisphere of Mars, a window opens: Only in this season can water vapor efficiently rise from the lower into the upper Martian atmosphere. There, winds ...

Scientists find likely source of methane on Mars

The mystery of methane on Mars may finally be solved as scientists Monday confirmed the presence of the life-indicating gas on the Red Planet as well as where it might have come from.

NASA's Mars helicopter completes flight tests

Since the Wright brothers first took to the skies of Kill Devil Hill, North Carolina, Dec. 17, 1903, first flights have been important milestones in the life of any vehicle designed for air travel. After all, it's one thing ...

Asteroids, hydrogen make great recipe for life on Mars

A new study reveals asteroid impacts on ancient Mars could have produced key ingredients for life if the Martian atmosphere was rich in hydrogen. An early hydrogen-rich atmosphere on Mars could also explain how the planet ...

Anxiety abounds at NASA as Mars landing day arrives

A NASA spacecraft's six-month journey to Mars neared its dramatic grand finale Monday in what scientists and engineers hoped would be a soft precision landing on flat red plains.

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Atmosphere of Mars

Mars, the fourth planet from the Sun, has a very different atmosphere than that of the Earth. There has been much interest in studying its composition since the recent detection of a small amount of methane, which may signal life on Mars; it could also be a geochemical process or the result of volcanic or hydrothermal activity.

The atmosphere of Mars is relatively thin, and the atmospheric pressure on the surface varies from around 30 Pa (0.03 kPa) on Olympus Mons's peak to over 1155 Pa (1.155 kPa) in the depths of Hellas Planitia, with a mean surface level pressure of 600 Pa (0.6 kPa, or 6 millibars, or 0.087 psi), compared to Earth's 101.3 kPa, and a total mass of 25 teratonnes, compared to Earth's 5148 teratonnes. However, the scale height of the atmosphere is about 11 km, somewhat higher than Earth's 7 km. The atmosphere on Mars consists of 95% carbon dioxide, 3% nitrogen, and 1.6% argon, and contains traces of oxygen, water, and methane, for a mean molecular weight of 43.34 g/mole. The atmosphere is quite dusty, giving the Martian sky a tawny color when seen from the surface; data from the Mars Exploration Rovers indicate that the suspended dust particles are roughly 1.5 micrometres across.

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