Neptune
Neptune‘s atmosphere is made up of hydrogen, helium and methane. The methane in Neptune’s upper atmosphere absorbs the red light from the sun but reflects the blue light from the sun back into space. This is why Neptune appears to be blue. The Romans named the five planets closest to the sun after their most important gods. Later, when telscopes were used, other planets were discovered. Astronomers decided to continue naming the Planets after Roman Gods. Neptune was named after the Roman god of the Sea.
Neptune has thirteen moons (that we know of). The largest moon is Triton. Triton is slightly smaller than Earth’s moon and has active volcanoes which erupt like geysers and eject nitrogen frost over the surface. The other moons of Neptune are Nereid, Proteus, Larissa, Despina, Galatea, Thalassa, and Naiad. These moons are much smaller than Triton.
Neptune is the fourth largest planet in our solar system and it is the smallest of the giant gas planets. Neptune has a diameter of 34,503 miles (55,528) kilometers. Its volume is 57.7 times the volume of Earth.
The average distance of Neptune from the sun is 2,795,084,800 miles or 4,498,252,900 kilometers. Because its orbit is elliptical, its distance from the sun changes depending on where it is in its orbit. The closest Neptune gets to the sun is 2,771,087,000 miles or 4,459,630,000 kilometers. The farthest it gets from the sun is 2,819,080,000 miles or 4,536,870,000 kilometers.
Neptune has several rings around it. There are three main rings which are very thin and dark. The rings are made up of small rocks and dust. Neptune’s rings are not the same thickness all around. There are areas of the rings which are much thicker than other areas of the rings. These thicker parts are called ring arcs. Some of these ring arcs are also twisted. Because Neptune’s rings are so dark and faint, they were not discovered until the 1980′s.
The Great Dark Spot was a huge spinning storm in the southern atmosphere of Neptune which was about the size of the entire Earth. Winds in this storm were measured at speeds of up to 1,500 miles per hour. These were the strongest winds ever recorded on any planet in the solar system! The Great Dark Spot was first discovered when the Voyager 2 spacecraft flew by Neptune in 1989. When the Hubble Space Telescope looked at Neptune in 1994, the Great Dark Spot was gone and a different dark spot had appeared in the northern atmosphere of Neptune.
Because Pluto has an orbit around the sun which is very elliptical, there are times when it crosses Neptune’s orbit and becomes the 8th planet from the sun instead of the 9th. When this happens, Neptune becomes the 9th and farthest planet in the solar system. For 20 years, from 1979 to 1999, Neptune was actually farther from the sun than Pluto. For now, Pluto is back to being the 9th and farthest planet from the sun. It will be more than 230 years before Neptune and Pluto trade places again. Pluto slips inside of Neptune’s orbit once every 248 Earth years for a period of twenty years.
Important update: Neptune Finally Makes First Orbit Around the Sun Since Discovery In 1846.
