# Neptune

*In the Solar System*

The furthest planet, four and a half billion kilometres out, and the only one found by arithmetic before anybody looked: its position was worked out from the way it was pulling Uranus off course. It has the fastest winds in the Solar System, over 2,000 km/h, and Triton - a moon going round it backwards, which means it was captured, and which vents nitrogen at −235 °C.

| | |
| --- | --- |
| Radius | 24,764 km |
| Around the equator | 155,597 km |
| Mass | 1.02 x 10^26 kg |
| Compared with the Earth | 17 × |
| Turns once in | 15 h 58 m |
| From the Sun | 4,469,783,088 km (-3,611 km/d) |
| From the Earth | 4,327,974,556 km (-824,155 km/d) |
| A signal takes | 4 h 1 m |

Distances and speed are computed from JPL Horizons trajectories and are true of 2026-09-05, changing at the rate given beside each. The interpolation itself is good to a few kilometres; what ages these figures is the date, not the arithmetic.

## Elsewhere

- On the live map: https://www.orbitalmap.space/?world=solar-system&focus=neptune
- This object as a page: https://www.orbitalmap.space/o/neptune/
- Every object: https://www.orbitalmap.space/o/
- What this site is and what it reads: https://www.orbitalmap.space/llms.txt