Mars is the fourth planet from the Sun and is the second smallest planet in the solar system. Named after the Roman god of war, Mars is also often described as the Red Planet due to its reddish appearance. Mars is a terrestrial planet with a thin atmosphere composed primarily of carbon dioxide.

Mars has two small moons, Phobos and Deimos. They were discovered in 1877 by astronomer Asaph Hall, who named them for the Latin terms fear and panic. These moons are thought to be captured asteroids and are among the smallest natural satellites in the solar system.

Mars has the largest volcano in the solar system Olympus Mons. It measures some 600 kilometres across and rises nearly 27 kilometres above the surrounding terrain. It is a shield volcano built by the continuous action of flowing lava over millions and millions of years that began some 3 billion years ago.

Olympus Mons is part of a complex of volcanoes that lie along a volcanic plateau called the Tharsis Bulge. This entire region lies over a hotspot, a place in the planets crust that allows magma from deep inside to flow out to the surface.

The Valles Marineris is an extensive canyon system on the Mars equator. It is 4,200 kilometres long and, in places, is 7 kilometres deep. On Earth, it would span the entire North American continent and beyond.

Mars has has a very primitive form of plate tectonics, and the action of two plates past each other began splitting the surface some 3.5 billion years ago. That set the stage for the formation of the Valles Marineris.

Sources: https://solarsystem.nasa.gov/planets/mars/overview/ , https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html, https://astrogeology.usgs.gov/maps/mars-viking-hemisphere-point-perspectives First Published: June 2012Last Updated: May 2020Author: Chris Jones

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Mars Facts - Interesting Facts about Planet Mars