Mars, the Red Planet, has a cold, dry surface covered in iron-oxide dust. Evidence of ancient river channels and lakebeds shows it once had liquid water on the surface. It hosts the largest volcano and the deepest canyon in the Solar System. Mars is approximately 6,778 km across.
How to observe Mars
Mars is most rewarding in the weeks around opposition, but its apparent size varies greatly between oppositions. Wait until it is high, let the telescope cool, and look for the bright polar region and broad dark markings during steady moments. Dust can obscure surface detail.
Scientific context
Useful scale comparisons are 0.532 Earth diameters, 0.378 g surface gravity, 1.881 Earth years per orbit. These values are rounded from the catalogue measurements shown on this page.
- Radius
- 3,389 km
- Diameter
- 6,778 km
- Mass
- 6.417E+23 kg
- Mean density
- 3.936 g/cm³
- Surface gravity
- 3.71 m/s² (0.378 g)
- Mean temperature
- -63°C
- Orbital period
- 687 days (1.881 years)
- Semi-major axis
- 1.52 AU
- Mean sunlight travel time
- 12.64 minutes
Source: NASA Science ↗
At your observing time
3 Oct 2026, 14:54 UTC · Change observing time
- Apparent magnitude
- 1.1
- Disc diameter
- 5.7 arcsec
- Constellation
- Cancer
- Next opposition
- 19 Feb 2027, 15:44 UTC
