# Mercury

*In the Solar System*

The smallest planet and the nearest to the Sun, a cratered ball of rock a little larger than the Moon with a metal core taking up some 60% of its mass. It has almost no atmosphere, so the day side reaches about 430 °C while the night side falls to −180 °C, and there is water ice in the floors of polar craters the sunlight has never entered. It goes round the Sun in 88 days and turns three times on its axis for every two of those years.

| | |
| --- | --- |
| Radius | 2,440 km |
| Around the equator | 15,329 km |
| Mass | 3.3 x 10^23 kg |
| Compared with the Earth | 0.055 × |
| Turns once in | 58.6 d |
| From the Sun | 60,710,396 km (+776,494 km/d) |
| From the Earth | 205,700,976 km (-350,216 km/d) |
| A signal takes | 11 min |

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=mercury
- This object as a page: https://www.orbitalmap.space/o/mercury/
- Every object: https://www.orbitalmap.space/o/
- What this site is and what it reads: https://www.orbitalmap.space/llms.txt