Mars is the fourth planet from the Sun and the second smallest planet in the Solar System, after Mercury.
| Diameter | 6,794 km |
| Mass | 6.4219e23 kg |
| Temperature | 130 K (-143 °C) to 308 K (35 °C) |
| Composition | Percentage |
|---|---|
| carbon dioxide | 95.97% |
| argon | 1.93% |
| nitrogen | 1.89% |
| oxygen | 0.146% |
| carbon monoxide | 0.0557% |
| water vapour | 210 ppm |
| nitric oxide | 100 ppm |
| molecular hydrogen | 15 ppm |
| neon | 2.5 ppm |
| HDO | 850 ppb |
| krypton | 300 ppb |
| formaldehyde | 130 ppb |
| xenon | 80 ppb |
| hydrogen peroxide | 18 ppb |
| methane | 10 ppb |
Mars is a terrestrial planet that consists of minerals containing silicon and oxygen, metals, and other elements that typically make up rock.
Mars is home to the tallest mountain in the solar system. Olympus Mons, a shield volcano, is 21km high and 600km in diameter. Despite having formed over billions of years, evidence from volcanic lava flows is so recent many scientists believe it could still be active.