Neptune, Uranus’ Sister Planet
Neptune's atmosphere, as shown by Voyager 2. Image courtesy http://nasa.gov
Neptune, the eighth planet from the sun, is also known as Uranus’ sister planet. They are both gas giants, but Neptune is a little smaller than Uranus. They are both made of gases. They are both mostly made of hydrogen, helium and frozen methane. This frozen methane is what makes them both blue. They also both have rings, although they are not as impressive as Saturn’s, nor even as large as Jupiter’s. Some of Neptune’s rings do not even go all the way around the planet!
Neptune was the first planet discovered because of math. When Uranus was discovered, astronomers found that the planet was not always where they thought it should be. They thought there had to be another very large planet pulling it away from its normal orbit. It was finally seen in a telescope for the first time on September 23, 1846 by Johann Gottfried Galle. It was very close to where mathematical calculations had predicted it should be. Neptune was named for the Roman god of the sea because of its blue color.
Voyager 2 came within 3,ooo miles of Neptune in 1989 after 12 years. It had traveled 3 billion miles! The pictures it sent back increased our knowledge of the outer planets. There are no more plans to send a probe to the gas giants, but one mission is planned to go to Pluto.
