Mars, the fourth planet remotest from the Sun, has long been an object of close attention of world science. This planet is very similar to the Earth with one small, but fateful, exception - the atmosphere of Mars is no more than one percent of the volume of the Earth’s atmosphere. The gas shell of any planet is a determining factor shaping its appearance and surface conditions. It is known that all the solid worlds of the solar system formed under approximately the same conditions at a distance of 240 million kilometers from the sun. If the conditions for the formation of Earth and Mars were almost the same, then why are these planets so different now?
It's all about size - Mars, formed from the same material as the Earth, once had a liquid and hot metal core, like our planet. Proof - many extinct volcanoes on the surface of Mars. But the "red planet" is much smaller than the Earth. So, it cooled faster. When the liquid core finally cooled down and hardened, the convection process was completed, and with it the planet’s magnetic shield - the magnetosphere - disappeared. As a result, the planet remained defenseless against the destructive energy of the Sun, and the atmosphere of Mars was almost completely carried away by the solar wind (a giant stream of radioactive ionized particles). The "Red Planet" has turned into a lifeless desolate desert …
Now the atmosphere on Mars is a thin, discharged gas shell, unable to withstand the penetration of deadly solar radiation, which burns out the surface of the planet. The thermal relaxation of Mars is several orders of magnitude less than a similar indicator, for example, of Venus, whose atmosphere is much denser. The atmosphere of Mars, which has too little heat capacity, forms more pronounced daily average wind speeds.
The composition of the atmosphere of Mars is characterized by a very high content of carbon dioxide (95%). The atmosphere also contains nitrogen (about 2.7%), argon (about 1.6%) and a small amount of oxygen (not more than 0.13%). The atmospheric pressure of Mars is 160 times higher than that of the surface of the planet. Unlike the Earth’s atmosphere, the gas shell here has a pronounced variable character, due to the fact that the planet’s polar caps containing a huge amount of carbon dioxide melt and freeze over one annual cycle.
According to data from the Mars Express spacecraft, the atmosphere of Mars contains a certain amount of methane. A feature of this gas is its rapid decomposition. This means that somewhere on the planet there must be a source of methane replenishment. There can be only two options here - either geological activity, traces of which have not yet been discovered, or the vital activity of microorganisms, which can turn our idea about the presence of foci of life in the solar system.
A characteristic effect of the Martian atmosphere is dust storms, which can rage for months. This dense air blanket of the planet consists mainly of carbon dioxide with minor inclusions of oxygen and water vapor. Such a protracted effect is due to the extremely low gravity of Mars, which allows even a super-rarefied atmosphere to lift billions tons of dust from the surface and hold for a long time.
