Most attribute Neptune's discovery to mathematical mastery in the s. After the discovery of Uranus at the turn of the century, astronomers noticed it seemed to be affected by a strange gravitational tug.
This oddity led British mathematician John Couch Adams to calculate Neptune's potential position in the s. A couple of years later, French astronomer Urbain Le Verrier did the same. Neptune's Great Dark Spot is clearly visible in this image of the planet, taken in by Voyager 2. The calculations were finally confirmed in when German astronomer Johann Gottfried Galle used Le Verrier's predictions to locate the ice giant, which was dubbed Neptune after the Roman god of the sea.
Neptune is just one of two ice giants in our cosmic family, along with Uranus. It's blanketed in an atmosphere of hydrogen and helium, with traces of methane, water, and ammonia. Underneath an initial chilly layer, temperatures and pressures rapidly increase. Deep under its cloud tops, Neptune might sport a vast, roiling-hot ocean of water that envelops its rocky core. But not all scientists agree that the planet is cool enough for such liquid to stick around without evaporating. Methane in the atmosphere reflects blue light, painting the world in vibrant color.
In most pictures, Neptune seems to be a deeper and more brilliant blue than Uranus, which looks like a pale turquoise dot. But Neptune is likely similarly pale as its neighbor and just appears darker in images because of its greater distance from the sun. Still, according to NASA , there may be some other, unknown component of Neptune's atmosphere that colors the world a slightly different hue.
Neptune has 14 known moons as of Its largest celestial tagalong, Triton, is the solar system's only large moon that has a retrograde orbit, which means it zips around Neptune in the opposite direction than its host planet's rotation.
This curious orbital direction may be evidence that it wasn't always a moon. Instead, researchers propose Triton started as a binary system —similar to the dwarf planet Pluto and its moon Charon. As it passed by, Neptune's gravity kidnapped Triton from the pair and trapped it in orbit.
Triton has a thin atmosphere that seems to be growing warmer, but scientists are unsure why. Five known rings of rocks and dust encircle Neptune—all named after astronomers who helped bring to light details about the windy world.
Neptune also has several partial rings, known as arcs. Only one spacecraft has ever visited the dark blue world. Voyager 2 whipped by in , collecting captivating data and images.
Though many scientists have proposed additional visits, none have yet been approved. This nickname first arose during the months leading up to the Voyager 2 encounter in , when the cloud group was observed moving at speeds faster than the Great Dark Spot. The Small Dark Spot , a southern cyclonic storm, was the second-most-intense storm observed during the encounter.
It was initially completely dark; but as Voyager 2 approached the planet, a bright core developed and could be seen in most of the highest-resolution images. For reasons that astronomers are still not clear on, the interior of Neptune is unusually hot. In fact, Neptune gives off 2. Even without the Sun, Neptune glows.
This high amount of interior heat matched with the coldness of space creates a huge temperature difference. And this sets the winds blasting around Neptune. Deep down inside Neptune, the planet might have an actual solid surface.
But temperatures at this region would be thousands of degrees; hot enough to melt rock. And the pressure from the weight of all the atmosphere would be crushing. We have many interesting articles about Neptune here at Universe Today.
Astronomy Cast has some interesting episodes about Neptune. Does this definition only apply to gas planets? And if it does apply to gas planets only, what value do people get from this definition? Because there is no consistency when it comes to the depth liquid can be found on gas giants.
You go with what you know. What a bunch of half truths, distortions and just plain wrong. Neptune has a surface, depending on the temperature it will be solid or liquid.
Due to the pressure the ocean may be liquid hydrogen rather than water. Neptune is the eighth planet from the sun. It was the first planet to get its existence predicted by mathematical calculations before it was actually seen through a telescope on Sept. Irregularities in the orbit of Uranus led French astronomer Alexis Bouvard to suggest that the gravitational pull from another celestial body might be responsible.
German astronomer Johann Galle then relied on subsequent calculations to help spot Neptune via telescope. Previously, astronomer Galileo Galilei sketched the planet, but he mistook it for a star due to its slow motion. In accordance with all the other planets seen in the sky, this new world was given a name from Greek and Roman mythology — Neptune, the Roman god of the sea. Only one mission has flown by Neptune — Voyager 2 in — meaning that astronomers have done most studies using ground-based telescopes.
Today, there are still many mysteries about the cool, blue planet, such as why its winds are so speedy and why its magnetic field is offset. While Neptune is of interest because it is in our own solar system, astronomers are also interested in learning more about the planet to assist with exoplanet studies.
Specifically, some astronomers are interested in learning about the habitability of worlds that are somewhat bigger than Earth. Those that are closer to Earth's size are called "super-Earths", while those that are closer to Neptune's size are "mini-Neptunes. Like Earth, Neptune has a rocky core, but it has a much thicker atmosphere that prohibits the existence of life as we know it.
Astronomers are still trying to figure out at what point a planet is so large that it may pick up a lot of gas in the area, making it difficult or impossible for life to exist.
Neptune's cloud cover has an especially vivid blue tint that is partly due to an as-yet-unidentified compound and the result of the absorption of red light by methane in the planets mostly hydrogen-helium atmosphere. Photos of Neptune reveal a blue planet, and it is often dubbed an ice giant, since it possesses a thick, slushy fluid mix of water, ammonia and methane ices under its atmosphere and is roughly 17 times Earth's mass and nearly 58 times its volume, according to a NASA fact sheet.
These winds were linked with a large dark storm that Voyager 2 tracked in Neptune's southern hemisphere in This storm seemed to have vanished when the Hubble Space Telescope later searched for it. Hubble has also revealed the appearance and then fading of other Great Dark Spots over the past decade.
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