September 28 – Discovery of Jupiter’s moon, Ananke (1951)

Ananke is one of Jupiter’s many smaller moons.  It was discovered on September 28th 1951 by Seth Barnes Nicholson at Mount Wilson Observatory.  It takes its name from the mythological personification of “Necessity” (the word means something similar in Greek).  Ananke was the mother of the Fates (also kmown as the Moirai), their father being Zeus (surprise, surprise).


Ananke is an irregular retrograde satellite, and lends its name to the Ananke group  of similarly inclined moons, as at 14km in diameter it is the largest of the type (the other members being Praxidike, Iocaste, Harpalyke, ThyoneEuanthe, and Europie).  The retrograde motion and eccentric orbits of the group lend credence to the theory that they may all be the remains of asteroids captured by Jupiter.

As far as I am aware there are no photographs of Ananke that show it as anything more than a faint grey spot.

 ALSO TODAY . . . .

1852  —  Birth of Elizabeth Isis Pogson, the first woman to attempt to gain membership of the Royal Astronomical Society (it took five years for her to succeed).

1876  —  Discovery of asteroids 168 Sibylla (by J C Watson) and 169 Zelia by Paul and Prosper Henry (a rarity, classified as “O-type” in the SMASS-based system devised by Bus and Binzel).

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