Mars has an atmosphere, though it is different than our atmosphere here on Earth. The atmosphere of Mars is thin, cold, and dry and contains much less oxygen than the atmosphere of Earth. The oxygen content of the Martian atmosphere is only 0.13 percent, compared with 21 percent in Earth's atmosphere. Carbon dioxide makes up 95.3 percent of the gas in the atmosphere of Mars. It also contains nitrogen and argon and very small amounts of water and methane. Additionally, the atmospheric pressure on Mars is only about 1/100 that of Earth's!