Ancient relic points to a turning point in Earth's history 42,000 years ago

Originally published at: Ancient relic points to a turning point in Earth's history 42,000 years ago | Boing Boing


Well that’s not terrifying at all…


A cursory glance at these observations makes me wonder if we are not apt to draw conclusions with the wisdom of the present that were not as apparent in the era. vis: “We think that the sharp increases in UV levels, particularly during solar flares, would suddenly make caves very valuable shelters,” unless I am wrong UV light is not visible and so the only way that the observation makes sense is if there was also a huge peak in the rate of sunburn. As it is direct light the people of the time would be escaping one would think that sitting under a shady tree would work just as well. That is, I have to presume that vegetation was still in existence and if necessary it could be woven into some kind of shade???
There are all kinds of good reasons why people sheltered in caves and these would surely have predated 42K years. A defensible entrance being one of them and a cooler more even temperature environment being another. So after perhaps several millenium passed they might have just said I know all those old songs and the TV reception is terrible - let’s invent art. Presumably cave walls presented a more durable canvas too.


I would give this a while to settle down.

Research is done by people. People are pan narrans, the story-telling ape. We knew the poles flip. Now we have some evidence from trees that this may have affected the climate, from trees which cannot move into the shade at will. So we try fitting every other bit of evidence in with this new bit. If something is believed to have happened at 39,000 years ago or 45,000 then they may get dragged in if they fit with the story, and may get rejected if they don’t.

There is a lot of energy in the Earth’s magnetic field. I tried calculating how much you would need to create a magnetic field for Mars - it was about 500 amps in a cable all around the equator which sounds possible, but the energies were enormous. So the Earth’s magnetic field may not have just shut off when it reversed, because all that energy has to go somewhere. But a sideways magnetic field does not give the same protection.

The Starfish Prime space atomic test in 1962 turned off the Van Allen belts for months. Several satellites were cooked, but hardly the End of Days. However, the winter of 62-63 felt a bit that way. Maybe the two were connected?


A good reminder of the time when we set off nuclear explosions with very little idea of what could happen. No idea if the yield would be accurate, what collateral damage could occur, etc etc. Crazy crazy.


UV light is invisible, but speaking as one who moved from the northern hemisphere to the southern: you can certainly feel it. The earth is closer to the sun during the southern-hemisphere summer than during the northern-hemisphere summer, and you can feel a sunburn happening here in a way that’s less obvious in the lower-UV north.

My first southern hemisphere sunburn was a very unpleasant surprise; until then, the worst I’d felt was something that tingled the next day, so when I felt the usual tingles I mostly ignored them (even if they were a bit louder than usual). This one stung for three days.

So it’s easy for me to imagine that our ancestors of 42,000 years ago would’ve noticed that shade was a much nicer place to be.


…yet a part of me still says “H-Bombs in Space, hells yeah! Young people today do science but they don’t do batshit like we did.” I don’t think that makes me a bad person. No-one who understands wants those days back.


UV, like blue light, is highly scattered by the atmosphere. So sitting under the acacia trees would only provide limited protection from sunburn.

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Oh, alas. All we have to work with is acacias. Who knew? Nevertheless, you can weave even grass into a mat that is impervious to light. Of course, this is only an issue during daylight hours. I always thought of cave dwelling to be a nocturnal thing. Anyways, those hunter gatherers had to eat and that cave was no supermarket. It is a pity that those early cave wall depictions of parasols have not stood the test of time.
I used to spend a lot of time in the (Southern Hemisphere) sun as a youngster. But by the time I was graduating high school - at the time that it was a worrying thing that CFCs were eroding the ozone layer - which was theoretically confined to the Antarctic but in actuality manifested in blotchy patches of ozone-depleted air masses being blown toward the Southern part of Australia - I had already noticed that the sun had a much stronger “bite” and seemed like about 15 minutes was enough to burn you. I live in the tropics now but still don’t spend a huge amount of time outdoors - perhaps because it’s bloody hot.

Solar flares, ionized air, aurora, and electrical storms would have been quite frightening.

“Yeah, purple lightning. That always good sign.”

The researchers theorise that the dramatic environmental changes may have caused early humans to seek more shelter.

“World ending! Only fallout cave save you! No-cave others eaten by giant sky demons! Low down payment accepted, soon as Grak invent concept of money.”

This could explain the sudden appearance of cave art around the world roughly 42,000 years ago.

OONA: “You give how many spearhead to Grak for this dump? Me not mate with dead mammoth in place like this.”
BAZ: “Okay, maybe me rush into deal, maybe not. You no complain when giant sky demons going to eat Oona!”
OONA: “Fine. Me do me best. Put up cave art. Put gazelle on wall. Maybe some handprint in corner tie cave together.”


EXTREME SCIENCE!!! Base jumping, ice diving, sciencing and other risky behaviour!

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Phew, this is palaeoclimatology, not ancient aliens theories. The term “relic” had me concerned.

I wouldn’t call tree rings relics, personally.


I found this very interesting article about Ochre which has a history of use running 300,000 years. Body art came before wall art. Primal baby. What the Ancient Pigment Ochre Tells Us About the Human Mind | Discover Magazine

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