Never dark, never seen: the far side of the Moon
Published
Earth’s tides have slowed the Moon’s spin until the same side always faces Earth: tidal locking[1]. So there is a side we never see. It is not dark, though. On average the near and far sides get almost equal amounts of sunlight[2]; “dark side” only ever meant unseen.
How much we see
The Moon wobbles a little as it goes round, so over time 59 % of its surface can be seen from Earth at one time or another[3]. The rest was unknown until 7 October 1959, when the Luna 3 probe took the first photographs of the far side[4]. The first soft landing there came on 3 January 2019, by Chang’e 4[5].
The far side is also shielded from Earth’s radio noise, which makes it a good place for radio telescopes[6].
The far side in the game
The game’s Moon is tidally locked too: its near side always faces Earth. One of its three high-orbit points, “Moon high far side”, sits 10,000 km above the middle of the far side. From there the whole Moon is in view, about 17° across.
- Earth is hidden. From the far side, Earth and Earth–Moon L1 are behind the Moon, so there is no link to L1. The way out is round to the Moon’s east or west point first. Nothing jumps through a body.
- It is in daylight. In game the Moon sits 5° off the line between Earth and the Sun, close to new moon. From Earth it is a dark disc beside the Sun, and its far side is lit: the “dark side” myth, turned round.
- The map is NASA’s CGI Moon Kit colour map, made from Lunar Reconnaissance Orbiter camera data. It is credited on the credits page.
The Moon in game is at its true size, 1,737.4 km in radius, and its true distance, 384,400 km: see A real-scale Earth and Moon. How the Moon’s points connect to Earth’s: Travel nodes.
Related
- 326,400 km out: the Earth-Moon L1 point
- 384,400 km apart: the Earth and the Moon at true scale
- 11 places, 14 links: how travel works in Hostile Flagship
- Credits
Sources
- Far side of the Moon, Wikipedia.
Tidal forces from Earth have slowed the Moon's rotation to the point where the same side is always facing the Earth—a phenomenon called tidal locking
- Far side of the Moon, Wikipedia.
In reality, both the near and far sides receive, on average, almost equal amounts of light directly from the Sun
- Far side of the Moon, Wikipedia.
In total, 59 percent of the Moon's surface is visible from Earth at one time or another
- Far side of the Moon, Wikipedia.
On 7 October 1959, the Soviet probe Luna 3 took the first photographs of the lunar far side
- Far side of the Moon, Wikipedia.
The China National Space Administration (CNSA)'s Chang'e 4 achieved the first ever soft landing on the lunar far side on 3 January 2019
- Far side of the Moon, Wikipedia.
Because the far side of the Moon is shielded from radio transmissions from the Earth, it is considered a good location for placing radio telescopes