Many people assume that rocks are dated at “millions of years” based on radiocarbon (carbon-14) dating. The most well-known of all the radiometric dating methods is radiocarbon dating.
Carbon-14 can yield dates of only “thousands of years” before it all breaks down.
If you ever wondered why nuclear tests are now performed underground, this is why. Well, there were no nearby supernovae that happened at that time, so that’s out.
There’s no evidence of an unusually large solar flare or any other bizarre solar activity, so that can’t be the culprit, either.
But once they interact with the atmosphere, They produce showers of subatomic particles of many different types, including — for our purposes — the all important neutron.
The reason neutrons are so important is because our atmosphere is 78% nitrogen, which you may remember as the thing that carbon-14 decays .
, and is so rare that only one-in-a-trillion carbon atoms are carbon-14.
With a half-life of just over 5,000 years, any Carbon-14 atoms that were created in stars, billions of years ago, have long since decayed away into nitrogen atoms.
As far as we can tell, the levels of carbon-14 throughout the world have remained roughly constant throughout the past few millenia, so that when an organism dies and the carbon-14 decays, we can measure how long ago it became deceased by measuring the ratio of carbon-14 to its normal carbon-12.
The only major fluctuation we know of occurred when we began detonating nuclear weapons in the open air, back in the mid-20th Century.
But that doesn’t seem likely; there is data from North American and European trees that this is consistent with!
If this confirmed, then there was very likely an extremely large increase in cosmic radiation over a very short period of time, the likes of which we’ve never seen or recorded, until now.
These excited neutrons then collide with nitrogen atoms in the atmosphere, changing them into radioactive carbon-14 atoms.