5 Things You Probably Didn't Know About Neptune

On September 23, 1846, German astronomer Johann Gottfried Galle discovered the planet Neptune, the eighth planet in our solar system. To celebrate this landmark event in astronomical history, here are five things you probably didn't know about the planet Neptune...

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The Discovery of Neptune is Still a Controversy The first person to have seen Neptune was likely Galileo, who marked it as a star in one of his drawings. However, since he did not identify it as a planet, he is not credited with the discovery.  That credit goes to French mathematician Urbain Le Verrier and the English mathematician John Couch Adams, both of whom predicted that a new planet – known as Planet X – would be discovered in a specific region of the sky. When astronomer Johann Gottfried Galle actually found the planet in 1846, both mathematicians took credit for the discovery.

Neptune Is The Coldest Planet in The Solar System The temperatures on Neptune can dip down -221.45 degrees Celsius (-366.6 °F). That’s almost three times the coldest temperature ever recorded on Earth (-89.2°C; -129°F), which means that an unprotected human being would flash freeze in a second!

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Neptune's Has The Fastest Wind Speeds In The Solar System Neptune's winds can reach speeds of up to 1,500 miles per hour, faster than the speed of sound. Scientists are puzzled exactly how an icy cold planet like Neptune can get its cloud tops to move so fast. One idea is that the cold temperatures and the flow of fluid gasses in the planet’s atmosphere might reduce friction to the point that it’s easy to generate winds that move so quickly.

Neptune Has Dark Rings Neptune has five rings, all named after people involved in the discovery of Neptune (Galle, Le Verrier, Adams, Arago, and Lassell). The rings are not bright like Saturn's, so it's difficult for people to spot the rings even with powerful telescopes. The rings may be the remnants of a moon that was destroyed in an inner orbit, possibly by Neptune's gravity.

Voyager 2 Is the Only Earth Spacecraft to Visit Neptune Despite all the probes and telescopes that have been launched from Earth, the only spacecraft that has ever visited Neptune was NASA’s Voyager 2.  Voyager 2 made its Neptune flyby on August 25, 1989, passing within 1,860 miles of the planet’s north pole. Voyager 2's data showed geysers on Triton (Neptune's moon) and dispelled the notion that the moon was all ice; it also proved the theory that Neptune has rings. Voyager 2 also viewed Neptune’s “Great Dark Spot“, the rotating storm system which has since disappeared, according to observations by the Hubble Space Telescope.