Mars is the planet known as the Red Planet in our Solar System.
Its reddish appearance comes mainly from iron minerals in the surface rocks and dust. These minerals oxidize, or rust, when exposed to oxygen and water, producing iron oxides that spread through the planet’s soil and atmosphere. From Earth, this gives Mars a noticeable red-orange color.
Mars is the fourth planet from the Sun and has a thin atmosphere dominated by carbon dioxide. It has two small moons, Phobos and Deimos, and a day lasting about 24 hours and 39 minutes. Its seasons resemble Earth’s because Mars has a tilted axis.
The Red Planet is not the hottest planet; Venus holds that record because its dense carbon-dioxide atmosphere creates an extreme greenhouse effect. Mars instead is a cold, dry world with polar ice caps, ancient valleys, volcanoes, and evidence that liquid water once flowed across parts of its surface.