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MARS AT A GLANCE

General

  • One of the five planets known to the ancients; Mars was the Roman god of war, agriculture and the state
  • Mars has a reddish color, and at times is the third brightest object in the night sky. (The Moon and Venus are first and second, respectively.)

Physical Characteristics

  • Average Diameter = 6,780 km; about half the diameter of Earth, and twice the diameter of the Moon.
  • Mars has the same land area as Earth; that is, the surface area of Mars is approximately equal to the land area of the Earth.
  • Mass = 6.4219 x 10 23 kg
  • Average Density = 3933 kg/m3
  • Equatorial Radius = 3397 km
  • There is no planet-wide magnetic field detected, there are only localized ancient remnant fields in various regions.

Orbit

  • Mars is the fourth planet from the Sun, the next beyond Earth
  • Mars is about 1.5 times as far from the sun as the Earth is.
  • It's orbit is elliptical, its distance from the Sun varies from 206.7 million km to 249.2 million km. Its average distance fromt the Sun is 227.7 million km.
  • It revolves around the sun once every 687 Earth days, so a Mars year is 687 Earth days.
  • A Mars day is 24 hours, 37 min, 23 sec, or 1.026 Earth days.

Environment

  • The atmosphere is composed chiefly of carbon dioxide (95.3%), nitrogen (2.7%) and argon (1.6%).
  • The atmospheric pressure is less than 1/100th that of Earth.
  • Surface winds can be up to 40 m/s (80 miles/hour)
  • There are local and regional dust storms, called whirlwinds or dust devils.
  • The surface temperature averages -53 °C (-64 °F) and varies from -128 °C (-199 °F) to 27 °C (80 °F).

Features

  • The highest point on the planet is Olympus Mons, a huge shield volcano about 26 km (16 miles) high and 600 km (370 mi) across, about the same area as Arizona.
  • The canyon system of Valles Marineris is the largest and deepest known in the solar system. It extends more then 4,000 km (2,500 miles) and reaches depths of 5 to 10 km (3 to 6 miles) from the surface.

Moons

  • Mars has two irregularly shaped moons, Phobos and Demios.
  • The largar moon, Phobos ("fear"), and the smaller moon Demios ("terror"), named for attributes personified in Greek mythology as sons of Ares, the god of war.