Exhibit Codex
Mars
A cold desert world with giant volcanoes, polar ice, and evidence of ancient flowing water.
Open interactive exhibit ↗About this exhibit
Terrestrial planet
Physical profile · seven measurements
- Mean radius
- 3,389.5 km
- Mass
- 0.641691 ×10²⁴ kg
- Bulk density
- 3.934 g/cm³
- Sidereal rotation
- 1.02595676 Earth days
- Sidereal orbit
- 1.8808476 Earth years
- Equatorial gravity
- 3.71 m/s²
- Escape speed
- 5.03 km/s
Present-day reference values, rounded from JPL Solar System Dynamics. These are not reconstructed ancient measurements. Gas-giant gravity refers to a reference atmospheric level, not solid ground. Sidereal rotation differs from the solar day.
Reference and coverage
Time scaling is shared with the interactive atlas. Surface interpretations and reconstructed history have different levels of certainty.
Planetary record
A desert with a wet past
Channels, deltas and water-altered minerals preserve evidence for ancient water. Today a thin carbon-dioxide atmosphere and low pressure make long-lived liquid water unstable at the surface.
Landmarks
Olympus Mons is a vast shield volcano. Valles Marineris is an enormous canyon system. Water ice exists at the poles and below parts of the surface.
Exploration
Orbiters, landers and rovers study climate, geology and past habitability. Evidence for habitable environments is not evidence that life has been found.
Time in this exhibit
4.6 billion years ago · Cloud & disk
The young Sun is surrounded by a disk of gas and dust. Planet formation is underway.
4.54 billion years ago · Young planets
The terrestrial planets are growing through accretion and impacts. Their orbits and surfaces continue to evolve.
Present · Modern system
Eight planets orbit our Sun. This layout compresses distances and adjusts sizes to make every world accessible.
Exhibit guide
Surface & interior
Mars has a rocky crust, mantle and metallic core. Volcanoes, impact basins, canyons and sedimentary deposits preserve a long geological record. Iron-bearing minerals contribute to the red surface.
Channels, deltas and water-altered minerals preserve evidence for ancient water. Today a thin carbon-dioxide atmosphere and low pressure make long-lived liquid water unstable at the surface.
Olympus Mons is a vast shield volcano. Valles Marineris is an enormous canyon system. Water ice exists at the poles and below parts of the surface.
Atmosphere & climate
The thin atmosphere is mostly carbon dioxide. Dust storms, seasonal polar frost and large temperature changes shape the environment.
Orbit & rotation
A Martian solar day lasts about 24.6 hours. Its year is about 687 Earth days. Axial tilt produces seasons, while the eccentric orbit makes them unequal in length.
Moons & water
Phobos and Deimos are its two small moons. Water ice survives, and surface landforms show that liquid water flowed in the past.
Exploration
Orbiters map the planet while landers and rovers examine local rocks and conditions. Ancient habitability and preservation of possible biological evidence remain major research questions.
Orbiters, landers and rovers study climate, geology and past habitability. Evidence for habitable environments is not evidence that life has been found.
Read the detailed records
Open the full exhibit Codex for individual structure records and time-specific information. The Credits page lists source creators, licenses and adaptations.