What’s on the Dark Side of the Moon?

What makes the dark side of the moon so mysterious and…uh…dark? Ask Science ventures into the unknown.

Lee Falin, PhD
3-minute read
Episode #26

What’s on the Dark Side of the Moon?

Imagine a warm summer night at the beach. You’re walking hand-in-hand with a loved one as the warm waves ripple against your bare feet. You gaze idly up at the full moon and a feeling of peace and happiness fills your heart.

But then something in your subconscious mind starts to gnaw away at this peaceful feeling. Something about the moon isn’t quite right. It looks familiar, too familiar. Haven’t you always been told that the moon is round? That it spins as it rotates around the Earth? Then why in the name of green cheese is the same side facing you tonight as it was last night?

You feel a slight tug on your arm. You look back towards your loved one, a questioning look in their eye. You just shake your head, all traces of peace now gone. Something sinister is going on with the moon. Why is the same side always facing the Earth? What’s happening with the other side, the side we never see; the dark side?

Beware the Dark Side

The first thing you should know about the dark side of the moon, is that it isn’t any darker than the rest of the moon. It’s called the “dark side” only because it appears dark or unseen to viewers here on Earth.

The reason for this is because of a phenomenon called tidal locking. Tidal locking takes place when one body orbits another and their respective gravitational influences pull on one another. After enough of this pulling takes place, the smaller object’s spin gets synchronized with its revolutions around the larger object. After that, only one side of the smaller object will ever face the larger one.

I’ve Got My Eye on You

Think about it like this: Imagine a fight scene from a cheesy action movie. The bad guy stands in the center of the room, while the good guy circles around him warily. As the good guy circles, his eyes stay fixed on his enemy, his body angled towards him slightly in case there’s an attack. Even though the good guy is constantly circling the bad guy he’s also constantly spinning his body so as to never turn his back on his enemy, the moon and Earth behave in a similar way (just without the animosity).

Ground Control to Major Tom

Okay, so now you understand why we can only see one side of the moon from Earth, but we still haven’t talked about what’s on the dark side of the moon. Why hasn’t anyone ever tried to explore it? Well we actually do know what’s on the far side of the moon. In the 1950s and 1960s several Russian satellites circled the moon and took pictures of it. In addition, multiple Apollo astronauts saw the far side of the moon with their own eyes while circling it in the 1960s and 1970s.

The reason NASA isn’t so keen on sending a manned or unmanned expedition there is because radio transmissions can’t be sent from the far side of the moon to the Earth. This would mean that any craft traveling there would be unable to contact mission control in the event of a problem.

Trust No One

And yet, all of these pesky facts haven’t stopped some individuals from coming up with their own ideas about what might be on the far side of the moon. Popular theories include an alien base or, alternatively, a secret U.S. military base, as well as the theory that the moon is a popular parking spot for UFOs that want to spy on Earth. Obviously.


So now you know a little more about the far side of the moon. If you’ve got your own theory about what’s out there, leave it in the comments below.

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Earth and Moon and Alien images from Shutterstock

Please note that archive episodes of this podcast may include references to Ask Science. Rights of Albert Einstein are used with permission of The Hebrew University of Jerusalem. Represented exclusively by Greenlight.

About the Author

Lee Falin, PhD

Dr. Lee Falin earned a B.S. in Computer Science from the University of Illinois, then went on to obtain a Ph.D. in Genetics, Bioinformatics, and Computational Biology from Virginia Tech.