Neptune is the eighth and farthest planet from the Sun in the Solar System. It is the fourth largest planet by diameter, and the third largest by mass. The planet is named after the Roman god of the sea. Discovered on September 23, 1846, Neptune was the first planet found by mathematical prediction rather than regular observation. Unexpected changes in the orbit of Uranus led astronomers to deduce the gravitational perturbation of an unknown planet. Neptune was found within a degree of the predicted position. The moon Triton was found shortly thereafter, but none of the planet's other 12 moons were discovered before the 20th century. Neptune has been visited by only one spacecraft, Voyager 2, which flew by the planet on August 25, 1989. Neptune is similar in composition to Uranus, and both have different compositions from those of the larger gas giants Jupiter and Saturn. Traces of methane in the outermost regions, in part, account for the planet's blue appearance. At the time of the 1989 Voyager 2 flyby, its southern hemisphere possessed a Great Dark Spot comparable to the Great Red Spot on Jupiter. Neptune has a faint and fragmented ring system, which may have been detected during the 1960s but was only indisputably confirmed by Voyager 2.

Read the rest of this article:
http://en.wikipedia.org/wiki/Neptune

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Today's selected anniversaries:

1885:

Mahdist War: British troops defeated Mahdist Sudanese forces at the Battle of Abu Klea in Khartoum, Sudan.
(http://en.wikipedia.org/wiki/Battle_of_Abu_Klea)

1899:

The United States took possession of Wake Island in the Pacific Ocean.
(http://en.wikipedia.org/wiki/Wake_Island)

1929:

Popeye the Sailor, a cartoon character created by E. C. Segar, first appeared in his newspaper comic strip Thimble Theater.
(http://en.wikipedia.org/wiki/Popeye)

1946:

The United Nations Security Council, the organ of the United Nations charged with the maintenance of international peace and security, held its first meeting at Church House in London.
(http://en.wikipedia.org/wiki/United_Nations_Security_Council)

1966:

The Palomares hydrogen bombs incident: A U.S. Air Force B-52 Stratofortress collided with a KC-135 Stratotanker during aerial refueling over the Mediterranean Sea, dropping three hydrogen bombs near the town of Palomares, Spain, and another one into the sea.
(http://en.wikipedia.org/wiki/Palomares_hydrogen_bombs_incident)

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Wiktionary's word of the day:

accentuate  (v)         1. To pronounce with an accent or vocal stress.
                              2. To bring out distinctly; to make prominent; to emphasize.
(http://en.wiktionary.org/wiki/accentuate)

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Wikiquote quote of the day:

All true histories contain instruction; though, in some, the treasure may be hard to find, and when found, so trivial in quantity, that the dry, shrivelled kernel scarcely compensates for the trouble of cracking the nut. Whether this be the case with my history or not, I am hardly competent to judge. I sometimes think it might prove useful to some, and entertaining to others; but the world may judge for itself. Shielded by my own obscurity, and by the lapse of years, and a few fictitious names, I do not fear to venture; and will candidly lay before the public what I would not disclose to the most intimate friend.   --Anne Brontė
(http://en.wikiquote.org/wiki/Anne_Bront%C3%AB)