A blue gas sphere isolated farthest from the Sun, Neptune is an ocean jewel in the coldest region of our solar system. Neptune’s atmosphere is hard to imagine from our Goldilocks perspective on Earth, placed in such perfect proximity to the Sun. The Sun’s effect on Neptune is weak, and unfathomably far away. So lonely and cold, what mysteries does Neptune hide?
• Neptune’s Discovery
Confirmed to exist in 1846 by astronomers Johann Galle and Heinrich Louis d’Arrest , Neptune was the first planet discovered by mathematical prediction rather than actual observation. A quirk in the orbit of the planet Uranus made astronomer Alexis Bouvard conjecture that something was affecting it gravitationally. A more massive gas giant observed a short time later was found to be the reason for the oscillation, and was named Neptune (a namesake borrowed from the Greek God of the sea).
• Strange Orbit
The cold “ice giant” has only been visited by one unmanned spacecraft, Voyager 2. This lack of visits is justified by the fact that Neptune is located thirty Earth-Sun distances (approx. 2,790,000,000 mi.) from its mother star. Neptune, in its elliptical orbit around the sun, can sometimes stray further from the star than even the dwarf planet, Pluto. Neptune is so far from the Sun that it takes 164 Earth-years for it to make a full revolution in orbit. In other words: two generations of human beings will die in the span of one Neptune orbital cycle.
• Life (or Lack Therof) on Neptune
Life and the atmosphere of Neptune are incompatible. Neptune harbors some of the coldest temperatures in our solar system, averaging -200° Celsius (-328° Fahrenheit). Unbreathable and deadly cold, the atmosphere of Neptune is composed of hydrogen, helium and trace amounts of methane. Obfuscated beneath the pressure of these clouds and a molten sphere of ammonia and water, is a solid core of iron and nickel kept under a pressure millions of times greater than Earth’s.
Incredibly fierce winds rip across the atmosphere of Neptune, caused by the planet’s magnetic field rotating slower than the planet itself. Wind gusts on Neptune rage at near-supersonic speeds, an astonishing two-thousand kilometers per hour (1242.742 mph). The most impressive Neptunian storms are called Great Dark Spots; these blemish the otherwise azure hue of Neptune with a darker blue color. Great Dark Spots are anti-cyclonic storms much like the Great Red Spot on Jupiter; however, Neptune’s largest storms do not last as long, and will dissipate every few years.
The presence of seasons is something that Neptune and Earth have in common, though Neptune bears a more severe 28.5° rotational tilt, compared to Earth’s 23.5°. Seasons on Neptune last a total of forty years, whereas Earth’s last three months.
• Rings and Moons
Though not boasting the phenomenal ring structure of Saturn, Neptune does have a small ring of ice and dust circling it. Neptune also boasts thirteen moons, although its only spheroidal moon is a rogue dwarf planet caught from the Keiper Belt named Triton. Triton is slowly being ripped apart by the much larger gravity of Neptune, and in 3.6 billion years will be a nameless cloud of space dust. Triton does hold its fame as the coldest place in the solar system at a chilling -236° Celsius (-392.8° Fahrenheit). Triton is also the only moon in our known solar system to orbit its host in a retrograde fashion.
So many things make Neptune unique. Neptune is a freezing gas giant at the edges of explored space with a deceptive, placid blue surface. The violent winds tearing its poisonous atmosphere apart, and the promise of doom it holds for its moon Triton, indicate the latent violence beneath the planet’s tranquil surface.
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