An ocean god for an ocean-colored planet

• Astronomers use Neptune’s fishing spear, the trident, for the planetary symbol.
• Neptune is the Roman equivalent of the Greek Poseidon, god of the sea.

A few scientific facts about Neptune:

• Neptune had to wait until modern times to have a planet named in his honor.
• In the early 1800’s, astronomers carefully observed the planet Uranus in order to determine its exact orbit around the sun.
• They found to their surprise, that its actual movement lagged a bit behind what their calculations were predicting.
• In 1820, French astronomer Alexis Bouvard began making tables predicting the movements of Jupiter, Saturn, and Uranus.
• The tables seemed to work for Jupiter and Saturn, but he found it impossible to predict where Uranus should be.
• Some believed there might be another planet beyond Uranus whose gravitational pull was slowing it slightly.
• An English astronomer, John Couch Adams, and a French astronomer, Urbain J. J. Leverrier, unknown to each other, both calculated where such a planet must be to account for the effect on Uranus.
• They both came out with the same results: Leverrier was the first to announce his results and on September 23, 1846, Johann Galle, in Berlin, confirmed the existence of a new planet, less than one degree from the predicted position and, behold, there was the eighth planet.
• It was named Neptune, not for any particular reason, but because Neptune was one important god who did not have a planet named in his honor.
• Neptune is another gas giant, similar in size and structure to Uranus.
• Although discovered in 1846, the eighth planet will not return to the position where scientists first saw it until 2011.
• Neptune orbits slowly because it is far from the Sun.
• In size and color, Neptune seems to be a twin to Uranus, but Neptune does not spin on its side; its axis tilts only a little more than that of Earth.
• The orbits of two moons, Triton and Nereid, crisscross the equator diagonally.
• Between Triton, the largest satellite, and the planet itself, six small, recently discovered moons also orbit.
• The planet is about seventeen times more massive than Earth.
• Astronomers now regard Neptune and Uranus as twin planets, somewhat alike in size, density, mass, and rotation.

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