Let’s say you were in the market to buy an authentic Leonardo Da Vinci painting. You will need two things.
First, a lot of money.
Second, a knowledge of nuclear bombs. Or, more specifically, isotopes created by the detonation of nuclear bombs.
Isotopes (atoms that have different numbers of neutrons than the standard for that element and therefore a different atomic mass) such as strontium-90 and cesium-137, did not exist in nature until 1945 when the first nuclear bombs were detonated.
Nuclear bombs (both the ones dropped over Japan in 1945 and the hundreds detonated in tests during the early Cold War period) created a thermonuclear explosion which resulted in neutrons of radioactive elements colliding in massive quantities to create new isotopes.
What does this have to do with buying a Da Vinci painting?
Well, Da Vinci lived during the 16th century, well before anyone had developed, let alone detonated, a nuclear bomb. And if you were to spend a fortune on a Da Vinci painting you would probably want to ensure it’s authentic.
One way to do that is to check for isotopes. If it is a masterful forgery (and many forgeries these days are highly convincing and often fool even expert art dealers) you should check whether the painting contains traces of these isotopes. If it does, you will know that it cannot pre-date 1945. So if the seller is purporting to offer an authentic Da Vinci and it contains these isotopes, you will know it’s a fake.
Of course there are other considerations to check for authenticity, but this one is pretty helpful. And it could save you a lot of money!