Mars, in astronomy: Physical Characteristics

Mars has a striking red appearance, and in its most favorable position for viewing, when it is opposite the sun, it is twice as bright as Sirius, the brightest star. Mars has a diameter of 4,200 mi (6,800 km), just over half the diameter of the earth, and its mass is only 11% of the earth's mass. The planet has a very thin atmosphere consisting mainly of carbon dioxide (95%) with some nitrogen, argon, oxygen, and other gases. Mars has an extreme day-to-night temperature range, resulting from its thin atmosphere, from about 80℉ (27℃) at noon to about −100℉ (−73℃) at midnight; however, the high daytime temperatures are confined to less than 3 ft (1 m) above the surface.

Sections in this article:

• Introduction
• Satellites of Mars
• Astronomical Characteristics
• Seasonal Changes
• Surface Features
• Physical Characteristics
• Bibliography

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