General Facts about Mars

ORBITAL PARAMETERS

 

  Mars Earth
Equatorial Mean Radius (x1011 m) 2.28 1.50
Sun Distance (UA) 1.38-1.67 0.98-1.02
Orbital Eccentricity 0.093 0.017
Orbital Inclination 1.85 0.00
LS at perihelion 251º 281º
Obliquity 25.19º 23.93º
Rotation (10-5s-1) 7.088 7.294
Passage 687 Earth's days-667 Mars' days 365.256 Earth's days
Satellites Phobos and Deimos Moon

 

 

PLANETARY FEATURES COMPARISON

 

Mars has a very small mass (about 10% of the Earth's mass) and a radius perceptibly smaller. Thus, Mars' surface gravity is 1/3 of the terrestrial.

  Mars Earth
Equatorial Radius (106m) 3.396 6.378
Mass (1024kg) 0.642 5.94
Density (g cm-3) 3.9 5.5
Surface Gravity (m/s2) 3.72 9.81

 

ATMOSPHERES COMPARISON. CHEMICAL COMPOSITION

 

  • Martian atmosphere is mainly compound of carbon dioxide, being water vapor ratio perceptibly smaller than terrestrial.
  • Molecular Oxygen proportion is also very small, thus atmosphere's Ozone is smaller than terrestrial too.
  • Next table shows atmospherical main gases proportion in each planet.

 

Compounds(%) Mars Earth
CO2 95 0.035
N2 2.7 78
O2 0.13 21
H2O 0.02 0-4
Ar 1.6 0.9
CO 0.07 0.00001
Ne 0.00025 0.0018
Kr 0.00003 0.000114
Xe 0.000008 0.000009
O3 0.000003 0.000004

 

  THERMODINAMICAL PARAMETERS COMPARISON

 

  • Martian atmosphere is very light (100 times lighter than terrestrial).
  • The pressure on the surface of Mars depends on the seasons. During Martian winter, the 30% of the Martian atmosphere condense at polar icecaps.
  • The temperature has a higher range of variation. This is caused by the lack of a thermodynamic regulator as terrestrial oceans are.
  • Dust storms are common and they can be active during months.

 

  Mars Earth

Gas constant R(m2s-2K-1)

192 287

Specific heat capacity at constant pressure(m2s-2K-1)

730 1010

Pressure on the surface (hPa)

7(VARIABLE)

1013

Temperature on the surface (K)

140-300 230-315

Mean density (kg/m3)

0.015 1.2