From the Earth, we always see the same face of the Moon. The other is sometimes called the “dark side”.
The question
Is the far side of the Moon always in darkness?
What you do Move the month on, from full Moon to full Moon. Look at the Moon from the Earth, then from the other side: where is the day, where is the night? Try a Moon that does not turn on its axis, too.
Without JavaScript, here are the animation’s data.
| Period | Hours | Source |
|---|---|---|
| One turn on its axis (relative to the stars) | 655.7 | 1 |
| One lunar day (from one noon to the next, at the same place) | 708.7 | 1 |
| Fact | Value | Source |
|---|---|---|
| One turn on its axis, one trip round the Earth | the same time | 2 |
| Each half of the Moon | two weeks of day, then two weeks of night | 3 |
The animation’s month (29.5 days) is calculated from NASA’s lunar day (708.7 hours). Sizes and distances are not to scale; the orbit is drawn as a circle, and the Moon’s slight rocking (libration, which shows us 59% of it over time) is not shown.
The takeaway The far side is in night no more often than the near side: at new Moon, it is in full daylight. We never see it because the Moon takes the same time to turn on its axis as to go round the Earth.
Photo credits 2
- Map of the Moon’s surface, made by NASA’s Scientific Visualization Studio (equirectangular projection). NASA's Scientific Visualization Studio, Public domain, source
- The Earth photographed on 7 December 1972 by the Apollo 17 crew on their way to the Moon: Africa, Antarctica and the Arabian Peninsula are visible. NASA, Apollo 17 crew, Public domain, source
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Sources 3
Williams, David R., “Planetary Fact Sheet – Metric”, NASA Goddard Space Flight Center (NSSDCA), updated 18 March 2025, rows “Rotation Period (hours)” and “Length of Day (hours)”, column Moon (fourth value).
Rotation Period (hours) 1407.6 -5832.5 23.9 655.7 […] Length of Day (hours) 4222.6 2802.0 24.0 708.7
Open access open the source · checked on 28 October 2026
Fraknoi, Andrew, Morrison, David and Wolff, Sidney C., Astronomy 2e, OpenStax, 2022, chapitre 4 “Earth, Moon, and Sky”, § 4.5.
rotates on its axis in exactly the same time that it takes to revolve
Open access open the source · checked on 9 September 2026
Fraknoi, Andrew, Morrison, David and Wolff, Sidney C., Astronomy 2e, OpenStax, 2022, chapitre 4 “Earth, Moon, and Sky”, § 4.5 “Phases and Motions of the Moon”, introductory paragraph (before the subheading “Lunar Phases”) and last paragraph (section “The Moon’s Revolution and Rotation”).
[…] with the Moon starting dark and getting more and more illuminated by sunlight over the course of about two weeks. After the Moon’s disk becomes fully bright, it begins to fade, returning to dark about two weeks later. […] The back side is dark no more frequently than the front side. Since the Moon rotates, the Sun rises and sets on all sides of the Moon.
Open access open the source · checked on 9 September 2026