Mars (astronomy)

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Fourth planet from the Sun. It is much smaller than Venus or Earth, with a mass 0.11 that of Earth. Mars is slightly pear-shaped, with a low, level northern hemisphere, which is comparatively uncratered and geologically ‘young’, and a heavily cratered ‘ancient’ southern hemisphere.

Mean distance from the Sun
227.9 million km/141.6 million mi

Equatorial diameter
6,780 km/4,210 mi

Rotation period
24 hours 37 minutes

Year
687 Earth days

Atmosphere
95% carbon dioxide, 3% nitrogen, 1.5% argon, and 0.15% oxygen. Red atmospheric dust from the surface whipped up by winds of up to 450 kph/280 mph accounts for the light pink sky. The surface pressure is less than 1% of the Earth's atmospheric pressure at sea level

Surface
the landscape is a dusty, red, eroded lava plain. Mars has white polar caps (water ice and frozen carbon dioxide) that advance and retreat with the seasons

Satellites
two small satellites: Phobos and Deimos

The flags of Qatar and Bahrain are very similar, reflecting the countries' historical links. The proportions of the Qatari flag are unique. Effective date: c. 1949. >>