Mars is smaller than the Earth, with an equatorial radius of 3,395km, which is half of the Earth's, its volume is less than 1/6 of the Earth's, and its mass is only110 of the Earth's. The rotation of Mars is very similar to that of the Earth, with a rotation of 24 hours, 37 minutes and 22.6 seconds. A day and night on Mars is slightly longer than a day and night on Earth. Mars makes a revolution of about 687 days, and a year of Mars is about two years for the Earth.

There are obvious seasonal changes on Mars, which is its main similarity with the Earth. But beyond that, Mars is very different from the Earth. The surface of Mars is a desolate world, and carbon dioxide in the air accounts for 95%. The dense carbon dioxide atmosphere causes the high temperature on Venus, but on Mars, the situation is just the opposite. The atmosphere of Mars is very thin, and its density is less than 1% of the earth's atmosphere, so it is impossible to store heat. This causes the surface temperature of Mars to be extremely low, rarely exceeding 0℃. The lowest temperature at night can reach-123℃.