Earth vs Mars: Size, Gravity, Day Length and Life, in 3D
Mars is the planet most like Earth, and still a very different world. It is about half as wide, its gravity is about a third of ours, its air is thin and mostly carbon dioxide, and it is far colder. But its day is only about 40 minutes longer than ours.
Earth vs Mars: true size
Earth vs Mars at a glance
| Earth | Mars | |
|---|---|---|
| Diameter | 12,742 km | 6,779 km, about half |
| Mass | 1 Earth | About 0.11 Earths |
| Gravity | 9.8 m/s² | 3.7 m/s², about 38% of Earth’s |
| Day | 24 hours | About 24 hours 40 minutes |
| Year | 365 days | About 687 Earth days |
| Average temperature | About 15 °C | About −60 °C |
| Air | Mostly nitrogen and oxygen | Very thin, about 95% carbon dioxide, under 1% of Earth’s pressure |
| Moons | 1 | 2, Phobos and Deimos |
| Distance from the Sun | About 150 million km | About 228 million km |
Could people live on Mars?
Not without a lot of help. There is no air to breathe, the pressure is so low that water boils away at body temperature, and there is no magnetic field or thick air to block radiation from space. People would need sealed homes, spacesuits, and ways to make water, oxygen and food. Mars does have water ice under the ground and at its poles, which would be key for any base.
Why Mars is red
The surface is covered in dust rich in iron oxide, the same compound as rust. Fine dust in the thin air makes the Martian sky look butterscotch by day and turns sunsets blue.
Quick facts
- Olympus Mons on Mars is the tallest volcano in the solar system, about 22 km high.
- You would weigh only about 38% of your Earth weight on Mars.
- Light takes between about 3 and 22 minutes to travel from Earth to Mars, depending on where they are.
- Mars has seasons, because its axis is tilted by a similar amount to Earth’s.
- Several robot rovers have driven on Mars, including Curiosity and Perseverance.
See them in 3D
Earth vs Mars questions
How big is Mars compared to Earth?
Mars is about half as wide as Earth, 6,779 km against 12,742 km, and has about a tenth of Earth’s mass.
How long is a day on Mars?
About 24 hours and 40 minutes. A Martian day is called a sol.
How strong is gravity on Mars?
About 38% of Earth’s. Someone who weighs 50 kg on Earth would feel like they weigh about 19 kg on Mars.
Can humans breathe on Mars?
No. The air is very thin and about 95% carbon dioxide.
How cold is Mars?
On average about −60 °C, though a summer day at the equator can reach about 20 °C.
More face-offs: see all 3D comparisons.
The 3D Solar System is made by Julian Neagu, a solo founder in London, as part of VisionVix Simulators. It is free to use in the browser on desktop and phone, with no sign-up.