Home   Sun & Moon   Moon   Far Side

No Permanently Dark Side of the Moon

The notion that there is a permanently dark side of the Moon is wrong. But there is a far side of the Moon, a side we never see from Earth.

Close-up of the far side of the Moon with partial Earth in the background.

The far side of the Moon in front of Earth.

We can never see the far side of the Moon from Earth, but, thanks to satellites and spacecrafts, we can see pictures of it.


The Moon does not radiate its own light, but its surface reflects the Sun’s rays. Half of the Moon's surface is always illuminated, and during the course of a lunar month, most areas of the surface have about 14-15 days of sunlight. On the far side, the Moon phases are exactly opposite from the ones we see from Earth, on the near side. When we see the Moon fully illuminated at Full Moon, the far side is in darkness. When it is New Moon here, it is Full Moon on the far side.

A Mystery until 1959

Humans had no idea what the far side of the Moon looked like until October 1959, when a Soviet spacecraft, Luna 3, transmitted the first grainy images.

During the next five decades, the quality of lunar images has vastly improved, especially because of NASA’s Lunar Reconnaissance Orbiter (LRO), a spacecraft which has been orbiting the Moon collecting data since 2009. Today, we have detailed maps of the Moon’s topography, including of the once mysterious far side.

Why Do We Never See the Far Side?

Illustration of the Moon's position in space in relation to Earth and the Sun at New Moon.
The far side is fully illuminated at New Moon.
At New Moon, the side we see from Earth is in darkness, while the far side of the Moon is fully lit up by the Sun's rays.

The reason the same side of the Moon always faces Earth is that the Moon rotates around its axis at the same speed as it revolves around Earth. This effect is known as tidal locking, and it is caused by the tidal forces of our planet.

In the same way as the Moon exerts tidal force on our planet, causing tides on Earth, our planet exerts tidal force on the Moon. Earth is larger than the Moon, so its tidal force is much more powerful. Over time, this force has slowed down the Moon's rotation until it reached a speed matching the speed of its orbit around Earth.

Lunar Libration

However, there is a small variation to this rule. Since the Moon revolves around Earth on an elliptical path, the Moon's distance from Earth varies from day to day. The point of the orbit closest to Earth is called perigee, while the point farthest away is known as apogee.

Like all celestial objects with elliptical orbits, the Moon's speed varies a little on its path around Earth. It speeds up when it is closest and slows down when it is farthest away from us. At perigee, the Moon's orbital speed is a little faster than its rotational speed.

This variation in speed, along with other factors, causes an effect called lunar libration. From Earth, the Moon seems to rock slightly from north to south and wobble a little from east to west. Over time, it is possible to see up to 58% of the Moon’s surface, but only 50% at a time. In other words, over time, we can see up to 8% of the outskirts of the Moon's far side from Earth.

Far Side Conspiracy Theories

Moon phases on the far side of the Moon, Crescent, Quarter, and Full Moon.
Moon phases on the far side of the Moon.
The far side of the Moon has the same Moon phases as the side we see from Earth, at the opposite time.

A quick search on the web shows plenty of references to the “Dark Side of the Moon.”

It is the title of a widely popular album from 1973 by English rock band Pink Floyd. There are also several films with the same name, including an American 1990 science fiction thriller and fantasy action “Transformers: Dark Side of the Moon” from 2011, and the German thriller “Die dunkle Seite des Mondes” from 2015 involving a lawyer who becomes a wanted man after a psychedelic mushroom trip.

You will also find a vast amount of more or less humorous conspiracy theories about secret Moon bases and UFOs, along with images from the far side of the Moon showing what some claim to be structures created by humans or aliens.

Topics: Moon, Astronomy

Next Full Moon

Jul 9, 2017 at 12:06 am

Previous Full Moon

Jun 9, 2017 at 9:09 am

Times for Full Moon can vary by time zone. Dates are based on the local time in Washington DC. Change location


Moon Phases In Your City

Full Moon Names

  1. Traditional Full Moon Names
  2. Wolf Moon – January
  3. Snow Moon – February
  4. Worm Moon – March
  5. Pink Moon – April
  6. Flower Moon – May
  7. Strawberry Moon – June
  8. Buck Moon – July
  9. Sturgeon Moon – August
  10. Harvest Moon – September or October
  11. Full Corn Moon (Harvest) – September
  12. Hunter's Moon (Harvest) – October
  13. Beaver Moon – November
  14. Cold Moon – December

Moon Index

Moon Phase ChartMoon phases visualized in real time, the past or the future.

The 12 Months of the Year

  1. January
  2. February
  3. March
  4. April
  5. May
  6. June
  7. July
  8. August
  9. September
  10. October
  11. November
  12. December

Months of the Year

You might also like

Why 3 Shadows?

The Earth and the Moon cast 3 different shadows: umbra, penumbra, and antumbra. Why are there 3 types of shadows and how are they defined? more

What Is the Antumbra?

The antumbra is the lighter part of a shadow that forms at a certain distance from the object casting the shadow. It is involved in annular solar eclipses and planet transits. more

Lunar Eclipse Penumbral

What Is the Penumbra?

The penumbra is the lighter outer part of a shadow. The Moon's penumbra causes partial solar eclipses, and the Earth's penumbra is involved in penumbral lunar eclipses. more

What Is the Umbra?

The umbra is the dark center portion of a shadow. The Moon's umbra causes total solar eclipses, and the Earth's umbra is involved in total and partial lunar eclipses. more