Mars, the fourth planet in order of distance from the Sun,
must have been known since very ancient times, since when
at its best it can outshine any other planet or star apart from
Venus. Its strong red colour led to its being named in honour
of the God of War, Ares (Mars); the study of the Martian
surface is still officially known as ‘areography’.

Mars Data:

Distance from the Sun:
max 249 100 000 km (1.666 a.u.)
mean 227 940 000 km (1.524 a.u.)
min 206 700 000 km (1.381 a.u.)
Sidereal period: 686.980 days (= 668.60 sols)
Synodic period: 779.9 days
Rotation period: 24h 37m 22.6s (=1 sol)
Mean orbital velocity: 24.1 km s−1
Axial inclination: 23◦59
Orbital inclination: 1◦5059
Orbital eccentricity: 0.093
Diameter: equatorial 6794 km
polar 6759 km
Apparent diameter from Earth:
max 25
.7
min 3
.3
Reciprocal mass, Sun = 1: 3098 700
Mass, Earth = 1: 0.107
Mass: 6.421 × 1026 g
Density, water = 1: 3.94
Volume, Earth = 1: 0.150
Escape velocity: 5.03 km s−1
Surface gravity, Earth = 1: 0.380
Oblateness: 0.009
Albedo: 0.16
Surface temperature:
max +26 ◦C
mean −23 ◦C
min −137 ◦C
Maximum magnitude: −2.8
Mean diameter of Sun, seen from Mars: 21
Maximum diameter of Earth, seen from Mars: 46
.8