In his 1998 book, Yellow Sky: an alternative perspective about the human condition and history, Kenneth Lipton argues that high radon levels in southeastern Pennsylvania may provide evidence of prior high tech civilizations.

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    I'm not sure if this really counts as a "notable claim". A cursory search suggests this was written by a plumber and is based more on theology and hunches than real evidence
    – JMac
    Commented Apr 6, 2018 at 17:11
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    ... or Ancient Aliens. In a nutshell, no evidence at all.
    – user41580
    Commented Apr 6, 2018 at 17:24
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    You could ask the question "What would remain" may be on topic on the Physics site. Commented Apr 6, 2018 at 17:37
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    Welcome to Skeptics! We have a rule that only widely-held beliefs are in scope for this site (or at least, claims made by notable people and organisations that are widely seen). Please quote the actual claim you want us to investigate, rather than limit us to a particular type of evidence.
    – Oddthinking
    Commented Apr 7, 2018 at 1:24
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    @LaurenceClarkCrossen: Please take a step back and read the Welcome to Skeptics link. I am not saying you made a claim. I am saying to get this reopened, your question must be about whether a claim made by someone else [e.g. Lipton] is true, and we need that claim to be as clear and precise as possible. It is currently unclear what the specific claim by Lipton is.
    – Oddthinking
    Commented Apr 7, 2018 at 6:46

1 Answer 1


Isotopes of 7 elements could be found in small amounts 26,000 years after use of nuclear weapons, so it would be pretty easy to figure out if they were used in pre-historic Pennsylvania. Furthermore, radon is produced by decaying uranium or thorium, which just means that it's a good place to mine for large amounts of uranium (such as eastern Pennsylvania) and doesn't in any way indicate that there are small amounts of uranium waste there from weapons use.

Material Produced By Nuclear Weapons: All nuclear weapons derive at least part of their energy from nuclear fission. Without getting too technical, this essentially means you whack an element with a large nucleus, like uranium, hard enough for it to split into other elements. These elements are called fission products, and most are too unstable to stick around for more than a couple hundred years. So, they would likely not be detectable 26,000 years later.

There are 7 long-lived fission products that have half-lives between 200,000 and several million years and would definitely be detectable if produced 26,000 years ago. These elements can occur naturally, as natural nuclear reactors are possible, although they are very rare.

If these fission products were found in any abnormal amount outside of such a natural reactor they would indicate that nuclear weapons were used in the area. I can't find any information regarding large amounts of them being found in Pennsylvania, so there doesn't seem to be any evidence of nuclear weapon use as the books suggests.

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    @LaurenceClarkCrossen The Oklo uranium mine is the only natural nuclear reactor we know of on Earth (See Giter's link) but it was last active 2 billion years ago.
    – Kevin Fee
    Commented Apr 6, 2018 at 19:59
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    @LaurenceClarkCrossen: The people in the uranium mines would certainly be regularly tested for any radioactive isotopes, especially long-lasting ones since they would build up in miner's body until they become lethal. As for nuclear reactors, chances are we'd find the cities housing the thousands of people involved in making the bombs before we found a reactor.
    – Giter
    Commented Apr 6, 2018 at 20:42
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    @notstoreboughtdirt: The radioactive material would be spread around the area as fallout before settling down as just another layer of (unhealthy) sediment. I suppose all of the material could be washed away over time, but that just means either the isotopes would be found elsewhere, or there's no proof one way or the other that the event ever happened.
    – Giter
    Commented Apr 6, 2018 at 20:46
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    @LaurenceClarkCrossen: I think you are poorly informed about all the other stuff that would be found. Sure, concrete wouldn't be found, but if they're making nukes they probably also have glass, plastic, aluminum, platinum, gold, etc., and all of that stuff being found in one place is completely unnatural and easy to identify.
    – Giter
    Commented Apr 6, 2018 at 21:01
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    @LaurenceClarkCrossen: 8 wooden spears that are 350,000 years old were found in Germany in the 1990's. 26,000 years is several orders of magnitude too little to erase a high-tech civilization.
    – Giter
    Commented Apr 6, 2018 at 23:01

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