Overview
Neptune, named for the Roman god of the sea, is a brilliant blue planet on the edge of our Solar System. Like the sea it may seem tranquil, but it earns its nickname of “The Windiest Planet”.
Classification
Like Uranus, Neptune is classified as an ice giant. Ice giants are colder and smaller than the gas giants.
Size
Neptune is 4 times wider than Earth with a radius of 15,299.4 miles. It’s just a bit smaller than Uranus.
Rotation
One day on Neptune is 16 hours on Earth, whereas one year is 165 Earth years. Quick days and long years are normal for the planets in the outer Solar System.
Position
Neptune’s tilt is 28 degrees, 5 degrees farther than Earth’s. This means there are seasons. Neptune has an elliptical, oval-shaped orbit. There are times when Neptune’s orbit is farther from the Sun than Pluto. This is due to Pluto’s oval-shaped orbit. There is no likelihood that Neptune and Pluto will collide.
It takes 4 hours for light to reach Neptune because as the eighth planet, Neptune is 2.8 billion miles from the Sun.
Structure
Neptune has a solid core about the same mass as Earth. This makes up about 25% of Neptune. The core is made out of iron and magnesium-silicate.
Like Uranus, Neptune is an ice giant. This means that over 80% of Neptune’s mass is made up of hot dense but “icy” water, methane, and ammonia. There might even be a super heated, but not boiling, ocean under Neptune’s thick clouds. The ocean wouldn’t boil because of the intense atmospheric pressure. Neptune doesn’t have a solid surface. Instead of a surface, water and ice fuse with the atmosphere.
Neptune’s total structure makeup is about 25% rock, 60%-70% ice and 5%-15% hydrogen and helium.
When it comes to planetary mass, Neptune is number 3, despite being a little smaller than Uranus.
The average temperature of Neptune is -353 degrees F. This is very cold, yet not as cold as Uranus. Neptune gets its warmth, not from the sun but from the internal motion of its core.
Neptune has 1.14 times the gravity on Earth. If it had a surface, everything would weigh a bit more on Neptune than on Earth.
Atmosphere
The atmosphere is made up of hydrogen and helium with a bit of methane, but not as much methane as found on Uranus. The bright blue color of Neptune is caused by an unknown element, instead of methane like Uranus.
The winds on Neptune can be 3 times stronger than winds on Jupiter and 9 times stronger than those found on Earth. The winds have a top speed of 1,200 mph. That is about the speed of sound. A massive oval-shaped storm named the “Great Dark Spot” was spotted in 1989 at Neptune’s southern hemisphere. Though it has disappeared, it was large enough to fit all of Earth inside of it. Other large storms have appeared around the planet.
Moons and Rings
Neptune has 13 known moons and another one waiting to be confirmed. They are all named after Greek water deities and nymphs. Triton is the largest moon and orbits Neptune opposite to the planet’s rotation. Triton also has an atmosphere and geysers that shoot out ice, despite the surface temperature of -391 degrees F.
Neptune has 5 rings. They are named Galle, Leverrier, Lassell, Arago and Adams. The rings have arcs, which are clumps of dust. The Adams ring has four. They are named Liberté (Liberty), Egalité (Equality), Fraternité (Fraternity) and Courage. These arcs are thought to be stabilized by one of Neptune’s moons, Galatea.
Fun Facts
As mentioned earlier, Neptune is sometimes farther from the Sun than Pluto is due to its orbit.