What does Mars consist of?

The center of Mars likely has a solid core composed of iron, nickel and sulfur. It is estimated to be between 930 and 1,300 miles (1,500 and 2,100 km) in diameter. The core does not move, and therefore Mars lacks a planet-wide magnetic field. read more

The atmosphere of Mars is less than 1% of Earth’s, so it does not protect the planet from the Sun’s radiation nor does it do much to retain heat at the surface. It consists of 95% carbon dioxide, 3% nitrogen, 1.6% argon, and the remainder is trace amounts of oxygen, water vapor, and other gases. read more