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How big is Mars compared with Earth?
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Mars
An especially serene view of Mars (Tharsis side), a composite of images taken by the Mars Global Surveyor spacecraft in April 1999. The northern polar cap and encircling dark dune field of Vastitas Borealis are visible at the top of the globe. White water-ice clouds surround the most prominent volcanic peaks, including Olympus Mons near the western limb, Alba Patera to its northeast, and the line of Tharsis volcanoes to the southeast. East of the Tharsis rise can be seen the enormous near-equatorial gash that marks the canyon system Valles Marineris.
Mars is a small planet, larger only than Mercury and slightly more than half the size of Earth.123
Key comparisons between the two planets include:
- Radius: Mars has an equatorial radius of 3,396 km (2,110 miles) and a mean polar radius of 3,379 km (2,100 miles), compared to Earth’s equatorial radius of 6,378 km (3,963 miles).12
- Mass: The mass of Mars is only one-tenth that of Earth.12
- Surface Area: Mars possesses only 28 percent of Earth’s total surface area. However, because a significant portion of Earth is covered by water, the actual land areas of the two planets are considered comparable.12
- Gravity: Due to its smaller mass, Mars has a lower gravitational pull. Surface gravity on Mars is 3.72 meters per second squared, meaning objects weigh slightly more than one-third of what they would on Earth.12