The moon is made up of a substance that emits gamma rays. It bathes the planet in low levels of radiation, and has done so since humanity's inception. It is the same size that it is in real life, and the same distance from earth. The atmosphere is also similar to ours. How would this form of radiation benefit humanity and the rest of the planet?

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    $\begingroup$ Because of the atmosphere, the moon would not be a significant source of gamma radiation. If you wanted a world where organisms evolved in a high radiation environment, you'd have to put the source of radiation a bit closer. Even then, the only real change is increased calorie consumption from higher metabolisms required to repair damaged tissue more frequently. $\endgroup$
    – Ghedipunk
    Commented Jul 10, 2018 at 20:18
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    $\begingroup$ Howdy Incognito. "Benefit humanity" is a very broad phrase. Please remember the help center says "Effects of events or world elements, including biology, technology and magic, on specific aspects of that world's societies, cultures, and environment" are on-topic. Can you narrow this down to a specific aspect? $\endgroup$
    – JBH
    Commented Jul 10, 2018 at 21:27
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    $\begingroup$ What is low level? It's a totally arbitrary definition. Please be more specific $\endgroup$
    – L.Dutch
    Commented Jul 11, 2018 at 2:39
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    $\begingroup$ Do you mean the moon has an atmosphere similar to ours, or that the Earth's atmosphere is the same? $\endgroup$
    – Korthalion
    Commented Jul 11, 2018 at 9:40
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    $\begingroup$ "Benefit"? Are you assuming that bathing in gamma ray radiation will supply things like elastic bodies or impenetrable green skin? I feel like talking about benefits from gamma ray radiation (which is actually most likely to simply cause cancer and kill humans) is entering into a "write whatever you want" kind of science fiction. $\endgroup$ Commented Jul 11, 2018 at 16:20

9 Answers 9


I freely admit I'm reaching here:

It would make the moon unsuitable for an alien invasion fleet to set up a command base there. Their standard invasion protocol requires them to set up a command base on a natural satellite, out of reach of the locals, before orbital bombardment can begin. They took one look at our dangerously radioactive moon, and decided it would be easier to invade someone else.

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    $\begingroup$ Love the creativity $\endgroup$
    – user
    Commented Jul 11, 2018 at 1:09
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    $\begingroup$ +1 Just for the pure creativity $\endgroup$
    – krypticbit
    Commented Jul 11, 2018 at 1:37
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    $\begingroup$ I love it. And since those radioactive moons aren't too popular these days your planet became sort of a defense center for other races as well. You could build a whole plot on that since now the evil aliens look for ways to attack your planet anyway ;-) $\endgroup$
    – Ister
    Commented Jul 11, 2018 at 9:00

It wouldn't be any different.

The Earth's atmosphere absorbs gamma rays. This is a good thing, because gamma radiation is not helpful for humans or most other life.

  • $\begingroup$ What happens to all the air that absorbs gamma rays? I understand it ionizes, which would have radio implication, I think ozone implications and maybe lightning implications. $\endgroup$
    – user25818
    Commented Jul 10, 2018 at 21:05
  • $\begingroup$ @notstoreboughtdirt Maybe not-quite-northern-lights? No. those are caused by particles... But might they make something similar? $\endgroup$ Commented Jul 11, 2018 at 8:18
  • $\begingroup$ I beg to differ, low levels of gamma radiation are very helpful, we likely wouldn't exist without. The necessity, and thus ability to repair DNA (not only due to gamma radiation, but also other reasons) is vital, as is regular mutation followed by selection. Only ever mixing the same set of genes with the same genes from your sex partner doesn't bring you forward. Low levels of radiation thus not only isn't very harmful, on the contrary, they are indeed a positive thing. Else, we would probably still be some form of gooey slime stuff, not mammals. $\endgroup$
    – Damon
    Commented Jul 11, 2018 at 11:35
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    $\begingroup$ @Damon cosmic rays are a small fraction of your yearly radiation dose if you stay under the cloud layer. $\endgroup$
    – user25818
    Commented Jul 11, 2018 at 14:24

As Samuel said, there would be no change to humanity whatsoever. The gamma rays would not penetrate the Earth's atmosphere well enough to affect human DNA. However, depending on the strength of the radiation from the moon, we might see a stronger aurora effect.

I think what would be more notable is the effect on our society's development. Let's assume the world developed the same as it did without the radioactivity. Consider these two scenarios:

  1. Since so much radiation has to come from something, this means there could be a valuable radioisotope in the dust of the moon. NASA has been using decaying radioisotopes for long term power generation for decades. The prospect of unlimited energy has made the world more excited than ever before! Now capitalism has jump-started a gold rush to the valuable materials of the cosmos, causing massive investment in space exploration!

  2. Conversely, society has scorned space travel! In the Space Race with the USSR, the United States exposed all those Apollo Astronauts to radiation, killing them a few years after the missions ended. As a result, Human Space Exploration has been banned because of the inherent risk. With NASA now gone, anti-science rhetoric is at an all time high. The boundary between church and state has begun to thin...

  • $\begingroup$ Good points. There would likely be visual effects and societal changes. $\endgroup$
    – Samuel
    Commented Jul 10, 2018 at 21:07
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    $\begingroup$ Before we even think about putting men on the moon (or even in orbit), all that radiation would severely damage electronics in satellites put in orbit, as well as the mice, dogs, and chimps that we sent up before humans. We'd never send men beyond our upper atmosphere at all until we figured out a way to block the radiation. $\endgroup$ Commented Jul 10, 2018 at 21:33

As jedmeyer mentioned, there would likely be no direct effects from the radiation. The earth already gets hit with a lot of high frequency EM radiation, including gamma radiation, and very little of it gets through the atmosphere.

There would likely be quite a few secondary effects though:

  • Earth would have been warmer throughout it's history. All the extra radiation would be adding extra energy to the atmosphere, which has to go somewhere. How much warmer is hard to tell without exact numbers on the composition of the moon. This in turn, would likely have at least resulted in shorter ice ages, which would have had an impact on both evolution, and human society.
  • The exact atmospheric composition would likely be different, though by how much is hard to tell. It's well known that UV radiation is what produces almost all of the atmospheric ozone on Earth. Similar reactions occur for gamma radiation, though to a much lesser degree.
  • On the same note, lightning might be more common in the upper atmosphere. Ionizing radiation like gamma radiation can cause charge imbalan es that are conducive to creating lightning. Such effects occur relatively infrequently however (thermonuclear explosions for example can cause lightning, but it's mostly because of the atmospheric turbulence and charged particulates, not the radiation directly).
  • Man-made satellites would have lots of issues. Gamma radiation is a serious problem for electronics. It's possible to design systems that are radiation hardened, but they're far more expensive than regular designs. Most LEO satellites are not fully radiation hardened in real life, but in a world like you describe, they would have to be.
  • Human spaceflight will become almost impossible, with becoming an astronaut essentially being a death scentence.
  • The moon might look brighter in the night sky.
  • Baseline background radiation on the surface might be marginally higher (a few PPM at most). Anything that can be done to impacted by this would be, but the effects would be so small they likely would be unnoticeable except on a massive scale.

That last part is where most of the theoretical potential benefits come in. Bacteria and other things that already have a particularly high mutation rate would likely evolve faster and scientists would have another natural random number generator. That's about it though as far as benefits I can think of.


One non-benefit: A seriously radioactive moon would put a big crimp in our space program. Just about everything that's been tried in deep space has been tried on the Moon first. If the moon is hot enough to bathe Earth in gamma rays it's hot enough to play major havoc with the electronics of any nearby spacecraft--you probably can't even orbit it.


You weren't very clear on whether "humanity's inception" was an inclusive or exclusive timeframe, but either way it presents a problem since it means the moon has either been outputting a large amount of energy over billions of years or somehow got "turned on" once humanity appeared.

Still, the point is that this isn't natural at all and contradicts all current theories of moon formation. Therefore those theories are obviously wrong and the moon is giant spaceship parked there by ancient astronauts.

The radiation might just be the first layer of automated defenses that will fall under the control of whoever first reaches the bridge of the Lunar class starship, gains administrative rights over the ship's systems, and inherits the legacy of the Precursors. Or if you insist on the radiation itself being helpful, it might be part of an electronic countermeasures package designed to protect Earth from detection by roving bands of von Neumann machines bent on devouring all organic life.

  • $\begingroup$ Welcome to WorldBuilding.SE Teleka! Interesting idea. If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$
    – Secespitus
    Commented Jul 11, 2018 at 9:27

Now, if the radiation is coming from right below the surface from a claimable source, like radioactive isotopes, building a base on the moon might be more feasible. However, this depends on the amount that is radiated. Too high and there will be no space program, faint but detectable would work perfectly. We could have had project orion if the moon contained claimable nuclear material.


The periodicity that the moon brings via gravitational radiation (i.e. tides) creates a dynamic playground of wet/dryness that add complexity to the environment. This complexity is exploited in various ways by quite a few different organisms (consider a bird hunting in tidal pools, or a barnacle advancing further upshore).

If the moon emitted gamma radiation, which acts as a DNA mutagen, life on earth would have a similarly periodic landscape regarding the rate of mutation that occurs during meiosis (which is when parent DNA combines to form child DNA).

This would allow organisms to vary their behavior and in turn expect more or less variation in offspring. During times of dense population, or for parents that cannot offer a socioeconomic advantage, it might make sense to procreate when the moon is overhead--in hopes that the offspring benefits from the 1:1,000,000 shot that it will receive a beneficial mutation.

On the other hand, during times of sparse population, or in cases where the parents can offer an advantaged situation, it would be better to "play it safe" and procreate when the moon is not visible. This would minimize mutation generally and be culturally a move that indicates support for the status quo.

Realistically, I think that the x-ray moon children are just more likely to just be sickly--genetic evolution is not so potent on human timescales--but as a cultural phenomenon it might lead to an even stronger conservative/liberal divide than we have today.


It gives lifeforms an elevated tolerance to radiation.

Since the entire biology on Earth developed under moderate radiation it adapted to that radiation by optimizing our DNA mechanisms. As an benefit, humans (and other species) are able to withstand high radiation levels without lasting damages.

Advantages include fields as manned spaceflight, healthcare (less cancer) and nuclear industries. The main detriment is that governments have less scruple in using nuclear weapons.


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