NASA / Voyager 2 / PDS / OPUS / Ardenau4, CC0Neptune
The windiest world we know, found with mathematics before a telescope
Overview
Neptune is the eighth and farthest known planet orbiting the Sun. It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth. Compared to Uranus, its neighbouring ice giant, Neptune is slightly smaller, but more massive and dense. Being composed primarily of gases and liquids, it has no well-defined solid surface. Neptune orbits the Sun once every 164.8 years at an orbital distance of 30.1 astronomical units. It is named after the Roman god of the sea and has the astronomical symbol , representing Neptune's trident.
Source: Wikipedia
Why it matters
- Predicted from irregularities in Uranus's orbit and observed in 1846 within a degree of the predicted spot.
- Supersonic winds reach about 2,000 km/h — the fastest measured on any planet in the Solar System.
- Its large moon Triton orbits backwards and is probably a captured Kuiper belt object, with nitrogen geysers.
System
- Discovered
- known since antiquity
- Discoverers
- John Couch Adams, Johann Gottfried Galle, Urbain Le Verrier, Heinrich Louis d'Arrest
- Star
- Sun · G2 V · 5,772 K · 1 M☉
- System
- 8 known planets
Orbit in the Solar System
| World | Period | Distance | Radius | Mass | Temp. |
|---|---|---|---|---|---|
| Mercury | 88 d | 0.387 AU | 0.38 R⊕ | 0.055 M⊕ | 440 K |
| Venus | 224.7 d | 0.723 AU | 0.95 R⊕ | 0.82 M⊕ | 737 K |
| Earth | 365.2 d | 1 AU | 1 R⊕ | 1 M⊕ | 288 K |
| Mars | 687 d | 1.52 AU | 0.53 R⊕ | 0.11 M⊕ | 208 K |
| Ceres | 4.6 yr | 2.77 AU | 0.07 R⊕ | 0.94 ×10²¹ kg | — |
| Jupiter | 11.9 yr | 5.2 AU | 1 R♃ | 1 M♃ | 163 K |
| Saturn | 29.4 yr | 9.57 AU | 0.84 R♃ | 95.11 M⊕ | 133 K |
| Uranus | 83.7 yr | 19.16 AU | 0.36 R♃ | 14.53 M⊕ | 78 K |
| Neptune | 163.7 yr | 30.18 AU | 3.88 R⊕ | 17.08 M⊕ | 73 K |
| Pluto | 247.9 yr | 39.48 AU | 0.19 R⊕ | 13 ×10²¹ kg | 48 K |
| Haumea | 282 yr | 43.1 AU | 0.12 R⊕ | — | 50 K |
| Makemake | 306.6 yr | 45.6 AU | 0.11 R⊕ | 3.1 ×10²¹ kg | — |
| Eris | 561.3 yr | 67.9 AU | 0.18 R⊕ | 17 ×10²¹ kg | 43 K |
| Sedna | 12,676.2 yr | 544 AU | 0.08 R⊕ | — | 12 K |
By the numbers
- Radius
- 3.88 R⊕24,737 km
- Mass
- 17.08 M⊕102 ×10²⁴ kg
- Orbital period
- 163.7 yr
- Distance from Sun
- 30.18 AU4,515 million km
- Eccentricity
- 0.01nearly circular
- Mean temperature
- -200 °C73 K
- Gravity
- 11 m/s²1.12 g
- Day length
- 16.1 h0.7 Earth days
- Moons
- 16with a ring system
- Density
- 1.64 g/cm³
- Axial tilt
- 28.3°
Sources
Image: NASA / Voyager 2 / PDS / OPUS / Ardenau4, CC0 · CC0 · image page
Text: Wikipedia (CC BY-SA 4.0). Taglines and highlights are editorial.