The Atmosphere of Mars

The atmosphere of planets is an important variable that drastically affects the surfaces. For example, since the atmosphere of Venus is so thick, Venus is a barren and burning planet. The Earth's atmosphere is a vital factor to life on earth. Neptune is blue because of the composition of its atmosphere, mostly methane, and has storms up to 2,400 km/hr, the fastest winds in out of all the planets.

The Planets and Pluto. Not to scale.

Mars in particular has a thin atmosphere. It is 100 times thinner than that of Earth and composed of 95.3 percent carbon dioxide, 2.7 percent nitrogen, 1.6 percent argon, .13 percent oxygen, and .08 percent carbon monoxide, with trace amounts of water, nitrogen oxide, neon, hydrogen-deuterium-oxygen, krypton and xenon. The atmosphere is thick enough to support weather, clouds, and winds. Seasonally, the density of the atmosphere changes because the carbon dioxide freezes out of the air in the winter. Mars also has the largest dust storms in the solar system, capable of blanketing the entire planet for months. These dust storms occur because the airborne dust absorbs sunlight, which warms the surrounding atmosphere, causing warmers air to flow to colder regions, generating winds; gradually strong winds lift dust off the ground, creating huge dust storms.

Two images taken by the Hubble Space Telescope showing Mars before (left) and during (right) the great Martian dust storm of 2001. 

Some scientists believe that at one point in history, Mars had a thicker atmosphere, cloudy skies, and liquid water flowing on the surface. But then, throughout its history, a process called sputtering would have knocked away atoms from its atmosphere through impacts from energetic particles. This video explains the process. 

It is interesting to see that while Mars and Earth look drastically different, in the past Mars might have just been like the Earth of the present, capable of housing life. This is what the hopes of many scientists lie on, the chance that Mars will once again be able to house life. While it might seem like a scene straight out of a sci-fi movie, life on mars might not be in the too distant future.