Planet
Mars
A red world with Earthlike days and long, uneven seasons.
Mars spins in about 24.6 hours, so its day is close to ours, but its year lasts 687 Earth days. Its 25-degree tilt brings seasons, and its oval orbit makes them uneven in length. Every 780 days Earth overtakes Mars, and for a few weeks Mars appears to drift backward across our sky.
How it moves
- Mars orbits the Sun every 686.98 days at an average of 24.08 km/s.
- One rotation takes 24.6229 hours; a Martian solar day (a sol) is 24.6597 hours.
- Its 25.19-degree axial tilt gives Earthlike seasons, each roughly twice as long as ours.
- Because the orbit is eccentric (0.0935), northern spring lasts 194 sols while northern autumn lasts only 142.
- Earth catches up to Mars every 779.94 days (synodic period); around those passes Mars traces an apparent retrograde loop against the stars.
Facts
- Mean radius
- 3,389.5 km
- Mass
- 6.417e+23 kg
- Surface gravity
- 3.73 m/s²
- Rotation period
- 24.6229 hours
- Orbital period
- 686.98 days
- Average distance from the Sun
- 1.52366231 AU
- Eccentricity
- 0.0935
- Axial tilt
- 25.19°
- Mean orbital speed
- 24.08 km/s
- Known moons
- 2
- Discovered
- Known since antiquity
Northern spring on Mars lasts 194 sols, the longest of its four uneven seasons.
Sources: nssdc.gsfc.nasa.gov, science.nasa.gov