Neptune is the eighth and farthest planet from the Sun. Discovered in 1846, it is a cold, windy world that is much larger than Earth. Let’s learn some interesting facts about Neptune.
Facts about Neptune (everything you need to know)
Orbit
- Neptune orbits at a distance of 2.8 billion miles (average) from the Sun. 2.8 billion miles (4.5 billion km) is approximately equal to 30 Astronomical Units (AU). 1 Astronomical Unit is the average distance of Earth from the Sun. In other words, the distance of Neptune from the Sun is 30 times the distance of Earth from the Sun.
- Neptune takes about 165 Earth years to complete one revolution around the Sun.
1 Neptune year = about 165 Earth years
- Neptune takes about 16 hours to complete one rotation on its axis, making its day much shorter than a day on Earth.
1 Neptune day = about 16 hours
Physical Overview of Neptune
- Neptune is the third most massive planet after Jupiter and Saturn.
- Neptune is the fourth-largest planet by diameter, after Jupiter, Saturn, and Uranus.
- Water, methane, and ammonia make up a large portion of Neptune’s interior. These compounds exist in a hot, dense, and slushy fluid state under high pressure and temperature.
- Neptune’s upper atmosphere is mostly made up of hydrogen and helium with a small amount of methane.
- There is no true surface at Neptune. It has a small rocky core with roughly the same mass as Earth.
- Neptune is about 4 times wider than Earth.
Mean radius of Neptune = 24,622 km
Mean radius of Earth = 6,371 km
- Neptune is approximately 17 times more massive than Earth.
Mass of Neptune = 102.413 * 10^24 kg
Mass of Earth = 5.9724 * 10^24 kg
- Neptune is the densest of the four giant planets. However, its average density is still less than one-third of Earth’s.
Neptune’s average density = 1,638 kg / m3
Earth’s average density = 5,514 kg / m3
Rings of Neptune
All giant planets have rings around them. There are at least 5 main rings of Neptune. These are named Galle, Leverrier, Lassell, Arago, and Adams. The rings are mostly made of dust and the material is extremely dark.
Along with 5 main rings, there are 4 dust arcs named Fraternité, Égalité, Liberté, and Courage. These arcs are present in the outermost ring Adams.
(Also read: 10 quick facts about the Solar System)
Natural satellites of Neptune
There are 16 known moons of Neptune. Triton is the largest moon of Neptune. It is also the seventh-largest moon in our solar system.
Neptune vs Earth comparison
| Neptune | Earth | |
|---|---|---|
| Radius | 24,622 km (15,299.4 miles) | 6,371 km (3,959 miles) |
| Mass | 102.413 * 10^24 kg | 5.9724 * 10^24 kg |
| Planet type | Gas/Ice giant | Terrestrial |
| Position from the Sun | 8th | 3rd |
| Number of moons | 16 | 1 |
| Day length | ~16 hours | ~24 hours |
| Year length | ~165 Earth years | ~365 days |
| Time taken by sunlight to reach | ~4.1 hours | 8 minutes 20 seconds |
| Average distance from the Sun | 4.5 billion kilometers (2.8 billion miles) | 150 million kilometers (93 million miles) |
| Ring system | Yes | No |
Additional facts about Neptune
- Neptune was named after the Roman god of the seas.
- Neptune is the windiest planet in our solar system, with wind speeds reaching over 1,200 miles per hour (2,000 km/h) in some regions.
- Voyager 2 is the only spacecraft that has visited Neptune.