Mars

Physical Characteristics

Diameter

• 6,779 km (4,212 miles)

Mass

• 6.42 × 10²³ kg

Surface gravity

• 3.71 m/s²

This is about 38% of Earth’s gravity.

Density

• 3.93 g/cm³

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Temperature

Mars is generally cold because it is farther from the Sun and has a thin atmosphere.

Average temperature

• About −63°C (−81°F)

Typical range

• −125°C (−195°F) near the poles in winter
• Up to 20°C (68°F) at the equator during summer afternoons

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Gravity: 38% of Earth’s gravity.

Moons

• Mars has 2 small moons.
• Phobos
• Deimos

Atmosphere

• Mars has a thin atmosphere composed mostly of:
• ~95% carbon dioxide
• ~2.7% nitrogen
• ~1.6% argon
• Surface pressure is about 0.6% of Earth’s atmospheric pressure.
• This thin atmosphere means:
• Temperature changes rapidly
• Liquid water is unstable on the surface

Surface and Geology

Mars has many major geological features.

Olympus Mons

• Largest volcano in the solar system
• About 22 km (13.6 miles) high

Valles Marineris

• Massive canyon system
• About 4,000 km (2,500 miles) long

Mars also has:

• Ancient river valleys
• Polar ice caps made of water ice and frozen CO₂
• Global dust storms

Water

Evidence suggests Mars once had:

• Rivers
• Lakes
• Possibly oceans

Today water exists mainly as ice underground and in polar caps.

Periodic Table

• Oxygen (O)
• Silicon (Si)
• Iron (Fe)
• Magnesium (Mg)
• Aluminum (Al)
• Calcium (Ca)
• Potassium (K)
• Titanium (Ti)
• Sodium (Na)
• Sulfur (S)
• Phosphorus (P)
• Chlorine (Cl)
• Hydrogen (H) — as water/ice and hydrated minerals
• Carbon (C) — mostly as atmospheric CO2 and trace carbonates and organics
• Noble gases (Argon, Neon) — in the atmosphere in trace amounts