Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury .
In English, Mars carries a name of the Roman god of war , and is often referred to as the “Red Planet“ because the iron oxide prevalent on its surface gives it a reddish appearance that is distinctive among the astronomical bodies visible to the naked eye.
Mars is a terrestrial planet with a thin atmosphere , having surface features reminiscent both of the impact craters of the Moon and the valleys, deserts, and polar ice caps of Earth .
Internal structure
- Like Earth, Mars has differentiated into a dense metallic core overlaid by less dense materials.
- This iron(II) sulfide core is thought to be twice as rich in lighter elements as Earth’s.
- The core is surrounded by a silicate mantle that formed many of the tectonic and volcanic features on the planet.
- Elements in the Martian crust are iron, magnesium , aluminum , calcium , and potassium .
- The average thickness of the planet’s crust is about 50 km (31 mi).
- Earth’s crust averages 40 km (25 mi).
