---
title: "Moon: facts, distance and size – Krillion Space"
description: "The Moon is Earth's only natural satellite, a rocky world a little over a quarter of Earth's width. Size, distance and sourced facts."
url: https://krilion.app/atlas/moon
language: en-US
---

# Moon

Rocky moon. Depth 1 on the Krillion Space voyage, in the Inner Sol.

The Moon is Earth's only natural satellite, a rocky world a little over a quarter of Earth's width. It is the only place beyond Earth that people have walked on, and its rocks preserve a record of the early solar system.

![The Moon at depth 1 in Krillion Space, mapped with NASA's Lunar Reconnaissance Orbiter map.](https://krilion.app/assets/atlas/moon.webp)

## Fact sheet

- **Type:** Natural satellite
- **Moon of:** Earth
- **Distance:** About 384,400 km (238,855 miles) from Earth on average; Earth orbits about 150 million km (1 AU) from the Sun
- **Size:** Diameter about 3,475 km (2,160 miles), a little over a quarter of Earth's
- **Discovered:** Known since antiquity
- **On the voyage:** Depth 1, in the Inner Sol section of the route, between Earth and Mars

## Things to know

- The Moon takes about 27.3 days to orbit Earth, but a full cycle of phases takes about 29.5 days because Earth is moving around the Sun at the same time. ([NASA NSSDC](https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html))
- The Moon is drifting away from Earth by about 3.8 cm (1.5 inches) each year. ([NASA NSSDC](https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html))
- The leading explanation for its origin is that a Mars-sized body crashed into the young Earth and the debris came together to form the Moon. ([NASA](https://science.nasa.gov/moon/facts/))
- Ice is concentrated in permanently shadowed craters near the poles, and in 2020 the SOFIA airborne observatory confirmed water on the sunlit surface in Clavius Crater. ([NASA](https://science.nasa.gov/moon/facts/))
- With no thick atmosphere to hold heat, surface temperatures swing from about 127°C (260°F) in sunlight to about -173°C (-280°F) in darkness. ([NASA](https://science.nasa.gov/moon/facts/))

## Missions

Apollo 11 made the first crewed landing in 1969 and Apollo 17 the last of six in 1972, returning about 382 kg (842 pounds) of samples; India's Chandrayaan-1 detected signs of water across the surface in 2008, and more than 105 robotic spacecraft have been sent to the Moon.

## Sources

- [NASA – Moon: Facts](https://science.nasa.gov/moon/facts/)
- [NASA NSSDC – Moon Fact Sheet](https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html)
- [NASA – The Apollo Program](https://www.nasa.gov/the-apollo-program/)

## On the route

- Previous landmark: [Earth](https://krilion.app/atlas/earth)
- Next landmark: [Mars](https://krilion.app/atlas/mars)
- [The whole Star Atlas](https://krilion.app/atlas)
- [Fly the voyage yourself](https://krilion.app/d/): every right answer warps your ship one stop deeper.