Mars has a diameter of about 4,212 to 4,222 miles (approximately 6,779 to 6,794 kilometers), which is roughly 53% the diameter of Earth, making it a little more than half the size of our planet
. Its radius is about 2,106 miles (3,390 kilometers)
. Mars is not a perfect sphere; it is slightly flattened at the poles due to its rotation, with an equatorial diameter slightly larger than the pole-to- pole diameter
. In terms of volume and mass, Mars has about 15% of Earth's volume and roughly 11% of Earth's mass, resulting in a surface gravity about 38% that of Earth
. Despite being smaller, Mars has a surface area comparable to all the dry land on Earth due to Earth’s large proportion of ocean coverage
. Additional notable size features include:
- Olympus Mons, the largest volcano in the solar system, is about 14 to 17 miles (22 to 27 kilometers) high and 370 to 624 miles (600 to 1,000 kilometers) in diameter
- Valles Marineris, the largest canyon system on Mars, stretches about 1,300 miles (2,100 kilometers) long, up to 300 miles (500 kilometers) wide, and about 5 to 7 miles (8 to 11 kilometers) deep
In summary, Mars is about half the size of Earth in diameter, with a smaller mass and gravity, but it has significant geological features that are the largest in the solar system.
