Themisto, also known as Jupiter XVIII, J XVIII, S/1975 J 1 or S/2000 J 1, is a moon orbiting Jupiter. Themisto has a mass of 689,387,479,224,709 kilograms, a volume of around 270 kilometers cubed, a surface area of around 200 kilometers squared, a mean radius of 4 kilometers, a circumference of around 25 kilometers, a diameter of 9 kilometers, a mean density of 2.6 grams per centimeter cubed and a temperature of around 124 Kelvin or Negative 149.15 degrees Celsius. Themisto has an orbital period around Jupiter of 130 Earth Days with an orbital velocity of 14891 kilometers per hour.
Profile of Themisto
Themisto was discovered first on September 30th, 1975, by American Astronomer Charles Thomas Kowal and American Astronomer Elizabeth Pat Roemer; then rediscovered on November 21th, 2000, by English-American Astronomer David Cliff Jewitt, Canadian-American Astronomer Yang Roland Fernandez and American Astronomer Eugene A. Magnier. The reason for the lost discovery is because an orbit for this moon was not established back in 1975 so it becomes a footnote in the 1980s and wouldn't be rediscovered until 2000. Themisto has a strange orbital patterns as opposed to other Jupiter moons, for unlike the other moons, which orbit in a system like the Galilean moons, Themisto orbits alone. Themisto was named after The Classical World's Themisto would was the daughter of Hypeseus, The King of The Lapiths, and wife of Athamas, The Boeotian King.
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