Neptune — the windy planet

Neptune is the farthest planet from Sun. It is also the windiest one.

Neptune’s dimensions

Neptune is a Neptunian planet because it is not as big as gas giants but not as small as rocky planets. It is about 3.9 Earths wide but only 17 times as massive. Also, its g-force is about 1.14 times as strong as Earth’s. That means if you weigh 100 kilograms on Earth, you’ll weigh 114 kilograms on Neptune. But of course, it has no clear surface because it is not rocky.

Neptune’s other features

Like Uranus, it has an atmosphere of hydrogen, helium and some methane, an icy mantle and a rocky core. It rotates quite quickly, taking just 16 hours for a day. It is the farthest planet from Sun at 30 astronomical units, hence it takes 165 years to orbit Sun once. In fact, Neptune has just passed a year in 2011 from its discovery in 1846. Also, it is the coldest planet, at about -200 degrees celsius. Also, its magnetosphere is off course, like Uranus, it is about 47 degrees from the spinning axis.

Interestingly, it is found by calculations of changes in the orbit of Uranus, similar to the radial velocity, a way to find an exoplanet. It was later confirmed in 1846.

Also, it is the windiest world in the Solar System, with wind speeds up to 2,100 kilometers per hour, almost Mach 2! Despite being very cold, the winds are 7 times stronger than a Category 5 hurricane. Moreover, there was a storm dubbed the ‘Great Dark Spot’. It has disappeared but new ones appear on the planet.

Neptune’s moons

Neptune has 14 moons and most of them are small, irregular ones. But Triton, a possible former dwarf planet, is the largest one in the class. It is in a retrograde orbit, which opposes the planet’s rotation. After Triton is being pulled by Neptune from the Kuiper Belt, it disrupts the moon’s orbit. Some moons’ orbits becomes very elongated, like Nereid’s, which is about 7 times closer to Neptune in periapsis than in apoapsis.

Now, Triton is getting closer and closer to Neptune, and will one day, perhaps millions of years later, crash into Neptune or form a Saturn-like ring. Also, Proteus, one of Neptune’s moon, is among the darkest object in the Solar System.

Neptune also has a dim ring system with about 5 main rings.

Relationship to the Kuiper Belt

Neptune also plays a critical role in the Kuiper Belt. Despite not being as large as Jupiter, its gravity is still very powerful and traps many celestial bodies into resonances, including Pluto, the former ninth planet. A lot of icy stuff share the same year too. They are plutinos, and they are the only group of objects that passes through Neptune’s orbit today, along with others in resonances.

Also, Haumea’s orbit seems to be in a 7:12 resonance and, Gonggong, a possible dwarf planet looks like to be in a 3:10 resonance, all with Neptune.

Media Credit: NASA’s Eyes