Can The Moon Be Hollow?

Axel Battista

Staff Writer

The moon is one of the biggest mysteries of ancient and modern societies. There are endless theories concerning the moon, ranging from where the moon came from to how it was formed. Some scientists claim the Earth’s only natural satellite came to be because of the gravitational pull of the Earth millions of years ago. Perhaps the moon was like any other asteroid and had drifted a bit too close to the Earth and is now eternally stuck revolving around us. 

Other scientists believe the moon was formed from a collision of an asteroid to the Earth. Some believe the moon is a chunk of Earth that somehow blew off. This prevailing theory is called the giant-impact theory, in which a Mars-sized asteroid collided with the Earth and some of the debris accumulated into what we know today as the moon. 

The actual composition of the Moon’s mantle is very similar to the Earth’s mantle, which leads most to believe that the two were once one floating chunk of rock. Prior to 1969, no human had ever stepped foot on the surface of the moon. The U.S. alone has six successful moon landings under its belt, with numerous unsuccessful attempts. 

One of the most infamous missions was Apollo 13, which would have been the seventh mission to the moon if not for the breached oxygen tank causing the astronauts to return home. Our lone satellite has been the source of many questions, hypotheses and conspiracy theories over the decades. 

Conspiracy theories are often ways for people to rationalize things they don’t understand or things that they don’t have any information on. They often stem from government actions or unexplained phenomena, although some conspiracies are created to deviate from the accepted truth of certain situations. The term usually has a negative connotation, with most theories being written off automatically as outlandish, although in recent years, the term “conspiracy theory” has shifted to mean a simple narrative that can or could possibly explain certain phenomena. 

Hollow Moon theory stems from Hollow Earth theory, which is a much bigger rabbit hole than one might think. Hollow Earth theory originated from Ludvig Holberg’s 1741 novel Niels Klim’s Underground Travels, in which the main character is exploring a cave in 1664 Norway. The man falls into the cave and reports feeling as though he was free-falling in space before being catapulted to the ground by a gryphon. 

You may be reading this and thinking this has to be a joke, that this is one of the most outlandish conspiracy theories you’ve ever heard, I would just like to assure you that the very first line in Holberg’s novel is that every event detailed in the novel is indisputably true. 

Hollow Moon theory is one of my all-time favorite conspiracy theories. I first heard of it on a podcast years ago and have been infatuated ever since. The moon is such a curious rock, with so many unanswered questions ranging from simple, “Why do wolves howl at the moon?” to complex, “If the moon was created by debris from impact, why didn’t the impact knock the Earth out of orbit?” 

Hollow Moon theory asks the question: “What’s inside the moon?” Some claim that the moon has a thin, hard crust and then is totally hollow in the middle, with dead air and no gravity. Others claim that the moon was originally a spaceship that got caught in Earth’s orbit. Most believers when faced with scientists and nonbelievers like to state that we have never drilled directly into the moon through to the center, or rather, as far as we can go.

We have done this on Earth, found the mantle and the crust and the core of the Earth, but we have never done the same on the moon. One of the first times that the Hollow Moon theory went public was in H.G. Wells’ novel The First Men in the Moon, in which the characters land on the moon and are met with not only a hollow moon but an alien species. 

Aliens aside, this book was one of the first times that this theory had shot to the forefront of the public’s mind, and was not just something that scientists readily wrote off as impossible. While there is no scientific evidence to back up this theory, there are two main points that believers of Hollow Moon theory fall back on: the bell sound and density. 

Between 1969 and 1977, multiple instruments called seismometers were installed on the surface of the moon, allowing astronauts and scientists to calculate and measure moonquakes, which are the moon equivalent to earthquakes. There are four different types of moonquakes, ranging from mere to severe tremors. This range also included surface-level or deep crust quakes. The shallow quakes, more often than not, were the moments when the moon would reportedly ring like a bell. 

Astronauts would report that the ground underfoot would shake and there would be an indistinguishable ringing in both the ears of those on the surface but also over any communication devices such as walkies or radios. The less convincing piece of evidence, density, relies on the fact that the moon is lighter than the Earth. If we believe the theory that the moon was created as a result of an impact with Earth, then the two would surely have the same density. 

However, the moon is significantly lighter than the Earth, therefore, the inside of the moon must be hollow. Smaller pieces of evidence of a hollow moon go from as simple as the rocks on the outside crust being a different composition than the rocks on the mantle (which supports the spaceship side of this theory), some of the moon craters are convex as opposed to concave which usually only happens to things that are hollow, and finally, that the shallow quakes are the only kind that report bell ringing because there is nothing past the mantle of the moon. 

Although there is much up in the air, the Hollow Moon Theory is an interesting theory to keep in the back of one’s head when looking up at night.

Categories: Opinions

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2 replies

  1. So your argument for the hollow moon has 2 components, the bell sound and density.

    The bell sounds caused by moonquakes could have a reasonable explanation. A team of 16 planetary scientists studied this effect for NASA and said the bell sound is likely the result of more solid rock on the moon compared to the earth’s crust, which has chemical weathering. This weathering will deaden the sounds caused by earthquakes. Here is an article explaining this effect:

    The density of the moon is 3.34 g/cm^3 while the density of the earth is 5.51 g/cm^3, so that argument seems to have some basis in fact. But, the earth has an iron core and the crust has a density of only 2.83 g/cm^3. Since the moon probably lacks an iron core of any significance, it is actually denser than the rocks making up the crust of the earth. Another data point is the 4 largest moons of Jupiter have a density between 1.8 and 3.5 g/cm^3. So the earth’s moon would seem to have a density at the upper end of the Jupiter moons, in other words totally unremarkable.

    As Carl Sagan once said, “extraordinary claims require extraordinary evidence” and this hollow moon claim has zero evidence.


  2. “Most believers… like to state that we have never drilled directly into the moon through to the center, or rather, as far as we can go.

    We have done this on Earth, found the mantle and the crust and the core of the Earth, but we have never done the same on the moon.”
    Err, no – we never needed to drill into the crust to find the crust – because we’re already standing on the crust! We have *never* drilled into the Earth and found mantle and the core.
    Hollow-earthers like to claim we need to drill a hole before we know what’s under the ground, but we don’t. Technologies far more sophisticated than eye-balling, are employed by geologists to determine the structure of our planet.


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