Phobos (moon)

Phobos (IPA {{IPA|/?fo?b?s/}}, Greek Φόβος: "Fright"), is the larger and innermost of Mars' two moons, and is named after Phobos, son of Ares (Mars) from Greek Mythology. Phobos orbits closer to a major planet than any other moon in the solar system, less than 6000 km above the surface of Mars, and is also one of the smallest known moons in the solar system. Its systematic designation is Mars I. The adjectival form of the name is Phobian, and in fairly common usage.

Discovery

Phobos was discovered by American astronomer Asaph Hall on August 18, 1877 at the US Naval Observatory in Washington, D.C at about 09:14 GMT (contemporary sources, using the pre-1925 astronomical convention that began the day at noon, give the time of discovery as August 17 16:06 Washington mean time). http://adsabs.harvard.edu//full/seri/AN.../0091//0000014.000.html. Asaph Hall also discovered Deimos, Mars' other moon.

Related Topics:
Asaph Hall - August 18 - 1877 - US Naval Observatory - GMT - August 17 - Washington mean time - Deimos

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The notebook of the discovery of Phobos by Asaph Hall is as follows:

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:"I repeated the examination in the early part of the night of 11th, and again found nothing, but trying again some hours later I found a faint object on the following side and a little north of the planet. I had barely time to secure an observation of its position when fog from the River stopped the work. This was at half past two o'clock on the night of the 11th. Cloudy weather intervened for several days.

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:"On Aug. 15th the weather looking more promising, I slept at the Observatory. The sky cleared off with a thunderstorm at 11 o'clock and the search was resumed. The atmosphere however was in a very bad condition and Mars was so blazing and unsteady that nothing could be seen of the object, which we now know was at that time so near the planet as to be invisible.

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:"On August 16th the object was found again on the following side of the planet, and the observations of that night showed that it was moving with the planet, and if a satellite, was near one of its elongations. Until this time I had said nothing to anyone at the Observatory of my search for a satellite of Mars, but on leaving the observatory after these observations of the 16th, at about three o'clock in the morning, I told my assistant, George Anderson, to whom I had shown the object, that I thought I had discovered a satellite of Mars. I told him also to keep quiet as I did not wish anything said until the matter was beyond doubt. He said nothing, but the thing was too good to keep and I let it out myself. On Aug. 17th between one and two o'clock, while I was reducing my observations, Professor Newcomb came into my room to eat his lunch and I showed him my measures of the faint object near Mars which proved that it was moving with the planet.

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:"On August 17th while waiting and watching for the outer moon, the inner one was discovered. The observations of the 17th and 18th put beyond doubt the character of these objects and the discovery was publicly announced by Admiral Rodgers."

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The names were suggested by Henry Madan (1838–1901), Science Master of Eton, from Book XV of the Iliad, where Ares summons Fear and Fright.

Related Topics:
Henry Madan - Eton - Iliad - Ares

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Phobos was photographed close-up by Mariner 9 in 1971, Viking 1 in 1977, Phobos 2 in 1988, Mars Global Surveyor in 1998 and 2003, and by Mars Express in 2004 .

Related Topics:
Mariner 9 - 1971 - Viking 1 - 1977 - Phobos 2 - 1988 - Mars Global Surveyor - 1998 - 2003 - Mars Express - 2004

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