Science Library - free educational site


Mars is the first planet outside the Earth's orbit, with a year 1.88 Earth years long. It has a very thin carbon dioxide atmosphere, and a mean surface temperature of a chilly -63°C.

    Vital statistics:
  • Mass: 6.4 x 1023 kg = 0.107 Earths/8.8 Moons
  • Diameter: 6779 km = 0.53 Earth's
  • Density: 3.93 tonnes/m3 = 0.713 Earth's density
  • Surface gravity: 3.7 m/s2 = 0.38g
  • Distance from Sun: 207 - 249 million km (227.9 Mkm semi-major axis) = 1.38 - 1.67 AU (Earth-Sun distances)
  • Period of orbit: 687.0 Earth days / 1.88 Julian years
  • Period of rotation: 1.03 Earth days (24.62 h)
  • No. of moons: 2
  • Atmosphere: 0.64 kPa (0.63% Earth's atmosphere), 96.0% CO2, 1.9% argon, 1.9% nitrogen, 0.15% O2, and trace gases, including 210 ppm (parts per million) water vapour.


Mars has two natural satellites, the small moons Phobos and Deimos.

Phobos, moon of Mars
Phobos, moon of Mars

Content © Renewable.Media. All rights reserved. Created : October 25, 2015 Last updated :December 27, 2015

Latest Item on Science Library:

The most recent article is:


View this item in the topic:

Vectors and Trigonometry

and many more articles in the subject:

Subject of the Week


Mathematics is the most important tool of science. The quest to understand the world and the universe using mathematics is as old as civilisation, and has led to the science and technology of today. Learn about the techniques and history of mathematics on


Great Scientists

Bernhard Riemann

1826 - 1866

Bernhard Riemann was a German mathematician whose revolutionary ideas of multi-dimensional space challenged Euclidean geometry perspectives, and ultimately led mathematics to radically new approaches, and found applications in many fields, such as General Relativity.

Bernhard Riemann, 1826 - 1866, German mathematician
Transalpine traduzioni

Quote of the day...

Mathematics is the language with which God has written the universe.

ZumGuy Internet Promotions