Glossary term: Mars

Description: Mars is the fourth planet from the Sun in the Solar System. It is named after the Roman god of war. It is often called the ‘red planet’ due to its reddish rusty color. It is a rocky planet and has a very thin atmosphere. It is the second smallest planet, with a radius roughly half of Earth's radius. Mars has large canyon systems, the tallest mountain in the Solar System and two small moons (Phobos and Demos). Scientists have sent many landers to Mars over the years to study its composition and atmosphere. Mars once had liquid water.

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Term and definition status: This term and its definition is still awaiting approval

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".

Related Media

The NASA Mars rover Curiosity stands on a hill on Mars.

Mars rover Curiosity

Caption: This self-portrait of NASA's Curiosity Mars rover shows the vehicle at the site from which it reached down to drill into a rock target called "Buckskin" on lower Mount Sharp. The selfie combines several component images taken by Curiosity's Mars Hand Lens Imager (MAHLI) on 5 August 2015, during the 1,065th Martian day, or sol, of the rover's work on Mars.
Credit: NASA/JPL-Caltech/MSSS credit link
License: PD Public Domain icons
The planet Mars with a rusty red surface, volcanoes, valleys, craters, ice clouds and a white polar cap


Caption: This image of the planet Mars taken by NASA's Mars Global Surveyor Orbiter in 1999 shows its dry surface. The picture features the most spectacular geological regions on Mars. Besides the deep Valles Marineris valley we see four volcanoes. While three of them form the Tharsis ridge, the Olympus Mons is largest volcano we have so far discovered in the Solar System. Ice clouds cover parts of the Martian surface.
Credit: NASA/JPL/MSSS credit link
License: PD Public Domain icons