Neptune was named after the Roman god of the sea.
After astronomers demoted Pluto to a dwarf planet, Neptune became the last planet in this solar system. Urbain Le Verrier, John Couch Adams and Johann Galle discovered Neptune on September 23, 1986. This was the first planet discovered through mathematical methods rather than telescope observation. The bulk of NASA's information on Neptune came from Voyager 2's 1989 documentation of the planet.
A Hue of Blue
Earth is not the only blue planet in this solar system. Neptune's vibrant blue hue is a widespread blanket across the planet. This vivid, bright blue is the result of methane in the atmosphere. NASA states that since Uranus's atmosphere also is composed of methane, but since its coloring is not as dramatic as the blue of Neptune, Neptune must have some unknown component that contributes to the intense, truer blue color.
Distant Gas Giant
Neptune cannot be seen without a telescope, even though it is almost four times the size of Earth at 30,776 miles in diameter. This is because Neptune sits 2.8 billion miles from the sun and roughly 2.7 billion from Earth.
Neptune is one of the gas giants, but it is the smallest of those. In addition to the methane, the gases present are hydrogen and helium. In comparison, Earth is mainly composed of nitrogen and oxygen.
Stormy Freeze
Beyond chilly, Neptune's temperature registers at minus 353 degrees Fahrenheit. According to Space.com's website, winds on Neptune are the fastest in the solar system, sometimes reaching 1,500 miles per hour.
In 1989, the Hubble telescope discovered an Earth-sized storm moving westward at 750 miles per hour. Subsequent satellite explorations showed these "Great Dark Spots" disappear and reappear.
Many Moons
William Lassell discovered Triton, the first known moon of Neptune, 17 days after the discovery of the planet. Now, NASA lists 13 moons in Neptune's Orbit. The moons are named for the nymphs and demigods in Greek Mythology and are as follows: Triton, Nereid, Naiad, Thalassa, Despina, Galatea, Larissa, Proteus, Halimede, Psamathe, Sao, Laomedeia and Neso.
National Geographic's website states, "Neptune's largest moon, Triton, is the coldest body yet visited in our solar system."
Neptune's Rings
While most pictures of Neptune do not show prominent rings, NASA reports that there are six small rings around the planet. These rings are not as solid as the rings around Saturn, but rather dusty arcs thought to be rather unstable and short-lived.
Longer Years, Shorter Days
Neptune will complete its first orbit around the sun since discovery in 2011. Due to the planet's vast distance from the sun, Neptune's year lasts 60,190 days or 165 Earth years. In contrast to the long year, the days on Neptune only last 16 hours.
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