Mars at a glance

Mars is the fourth of the Sun’s nine planets – the next outwards after Earth itself. It is the planet that most resembles Earth and although now dry, Mars was once probably awash with water. Mars has two tiny Moons, Phobos and Deimos, which may be captured asteroids.

Mean distance from Sun: 228,000,000 km/141,700,000 miles (1.524 AU)
Diameter: 6,792 km (4,220 miles)
Length of year: 687 days
Rotation period: 24 hr 37 min
Mean orbital velocity: 24.14 km/sec (15 miles/sec)

Phobos (left):
Mean radius: 11 km (6.8 miles)
Distance from Mars: 9,380 km (5,830 miles)
Period of Rotation: 0.3188 days
Deimos (right):
Mean radius: 6.2 km (3.9 miles)
Distance from Mars: 23,460 km (14,580 miles)
Period of rotation: 1.2625 days
Paul Sutherland

Paul Sutherland

I have been a professional journalist for nearly 40 years. I write regularly for science magazines including BBC Sky at Night magazine, BBC Focus, Astronomy Now and Popular Astronomy. I have also authored three books on astronomy and contributed to others.
Paul Sutherland

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