The beautiful blue orb of Neptune, named for the Roman god of the sea, is the eighth and farthest planet in our solar system from the sun. This honor used to reside with Pluto until it was demoted from planet status by the International Astronomical Union. Neptune's equator is four times as long as Earth's. It is 17 times as heavy, though not as dense. We have one moon, while Neptune has 11. And now, thanks to the Voyager 2 spacecraft and the Hubble Space Telescope, we can see Neptune as never before.

1 of 7 Hubble captures dynamic atmosphere NASA, ESA, E. Karkoschka (University of Arizona), and H.B. Hammel (Space Science Institute, Boulder, CO). Neptune is one of two planets not visible to Earth by the naked eye. This is perhaps the main reason why it was the first planet to be discovered by mathematical prediction. It was separately discovered in the mid-19th century by English astronomer John C. Adams and French mathematician Urbain Le Verrier. The planet is covered by thick clouds that move rapidly. NASA reports that Neptune's winds move at speeds up to 700 mph. This color-enhanced photo taken by the Hubble telescope in 2005 shows Neptune as never seen before.

2 of 7 Hurricanes NASA. Here two great hurricanes can be seen spinning on Neptune's surface. This photo was taken in August 1989 by Voyager 2, the only spacecraft to travel to Neptune. The Great Dark Spot is seen to the north, while Great Spot 2, with its white center, is more to the south. The white clouds in between were nicknamed "The Scooter" by NASA. The storms were thought to be swirling masses of gases similar to hurricanes on Earth. But when Hubble turned its telescope on Neptune in 1994, the storms had disappeared.

3 of 7 On Triton's horizon NASA. Voyager 2 generated this computer image of Neptune as seen from its moon, Triton. Triton is Neptune's largest satellite and is the only moon in the solar system to orbit opposite of its planet. Experts believe that Triton may have been a large comet that orbited the sun but got caught in Neptune's gravitational pull. Triton boasts the coldest known temperatures in the solar system, at minus 390 degrees F (that's minus 235 degrees C). NASA has discovered evidence of ammonia and water volcanoes on Triton.

4 of 7 Crescents of Triton and Neptune NASA/Ames Research Center. When Voyager 2 took this image, it "was plunging southward at an angle of 48 degrees to the plane of the ecliptic," according to NASA. Besides its 11 satellites, Neptune also boasts a planetary ring system. The three main rings are named for Neptune's first researchers, the Adams ring, the La Verrier ring and the Galle ring. But recent evidence shows that the rings are unstable and may be deteriorating in spots.

5 of 7 Great Dark Spot NASA. Voyager 2 took this photo of Neptune's gigantic anti-cyclonic storm in 1989. Considered to be much like Jupiter's Red Spot, the storm was thought to span 8,000 by 4,100 miles. It was believed to have a vortex structure. When Hubble turned its lens on Neptune in 1994, the Great Dark Spot was found to have vanished. A new storm just like it was found roaming the northern hemisphere of the planet.

6 of 7 Mosaic of Triton NASA/Jet Propulsion Lab/U.S. Geological Survey. This global color mosaic of Triton was taken by Voyager 2 in 1989. Like Earth, Triton is thought to have a nitrogen-rich atmosphere, and it is the only satellite in the solar system that has a nitrogen ice surface. The blue-green band across Triton is thought to be nitrogen frost, while the pink is thought to be methane ice.