Mars

Mars is the fourth planet from the Sun in our solar system. It is named after Mars, the god of war in Roman mythology (the counterpart to Ares in Greek mythology), because of its red color as viewed in the night sky. This feature also earned it the name "The Red Planet." Mars has two moons (Phobos and Deimos) which are both small and oddly-shaped, possibly being captured asteroids. The prefix areo- refers to Mars in the same way geo- refers to Earth—e.g. areology versus geology.

Observation of Mars

Earth passes Mars every 780 days (or two years plus seven weeks and one day) at a distance of about 80,000,000 km. However, this varies because the orbits are elliptical. To a naked-eye observer, Mars usually shows a distinct yellow, orange or reddish colour, and varies in brightness more than any other planet as seen from Earth over the course of its orbit, due to the fact that when furthest away from the Earth it is more than seven times as far from the latter as when it is closest (and can be lost in the Sun's glare for months at a time when least favourably positioned). At its most favourable times — which occur twice every 32 years, alternately at 15 and 17-year intervals, and always between late July and late September — Mars shows a wealth of surface detail to a telescope. Especially noticeable, even at low magnification, are the polar ice caps.

Related Topics:
Elliptical - July - September - Telescope - Polar ice cap

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On August 27, 2003, at 9:51:13 UT, Mars made its closest approach to Earth in nearly 60,000 years: 55,758,006 km (approximately 35 million miles) without Light-time correction. This close approach came about because Mars was one day from opposition and about three days from its perihelion, making Mars particularly easy to see from Earth. The last time it came so close is estimated to have been on September 12, 57,617 BC. Detailed analysis of the solar system's gravitational landscape forecasts an even closer approach in 2287. However, to keep this in perspective, this record approach was only an imperceptibly tiny fraction less than other recent close approaches that occur four times every 284 years. For instance, the minimum distance on August 22 1924 was 0.37284 AU, compared to 0.37271 AU on August 27 2003, and the minimum distance on August 24 2208 will be 0.37278 AU.

Related Topics:
August 27 - 2003 - Light-time correction - Opposition - Perihelion - September 12 - 57,617 BC - 2287 - August 22 - 1924 - AU - August 24 - 2208

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A transit of the Earth as seen from Mars will occur on November 10, 2084. At that time the Sun, the Earth and Mars will be exactly in a line. There are also transits of Mercury and transits of Venus, and the moon Deimos is of sufficiently small angular diameter that its partial "eclipses" of the Sun are best considered transits (see Transit of Deimos from Mars).

Related Topics:
Transit of the Earth as seen from Mars - November 10 - 2084 - Transits of Mercury - Transits of Venus - Deimos - Angular diameter - Transit of Deimos from Mars

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