Water under the bridge. (that is the right expression I hope?)
All atoms have what is called a half life. They are all slowly dieing, though extremely slowly. Uranium dies faster than most, and as such, releases a lot of energy which we harness. You can see the age of a sample by measuring the levels of a certain isotope (decaying atoms). They choose very particular elements though.
This is just one method however. They can also see at what level in the earth fossils were found. Annual rains deposit sediment in different amounts at the bottom of rivers for example. They can count the number of years the deposit has been building for, and, instead of counting 65 million, extrapolate the age simply by measuring the depth. Like counting rings of a tree.
I'm rusty on this, but this is what I remember. Radio carbon dating. I don't think this works for really old samples like 65 million years. They use a different method for that. They check the levels of a certain isotope to determine the substances age.juantoo3 said:How does science know it took place 65 million years ago? With the certainty you proclaim? Actually, I have done some homework, I'm checking to see if you've really done yours.
All atoms have what is called a half life. They are all slowly dieing, though extremely slowly. Uranium dies faster than most, and as such, releases a lot of energy which we harness. You can see the age of a sample by measuring the levels of a certain isotope (decaying atoms). They choose very particular elements though.
This is just one method however. They can also see at what level in the earth fossils were found. Annual rains deposit sediment in different amounts at the bottom of rivers for example. They can count the number of years the deposit has been building for, and, instead of counting 65 million, extrapolate the age simply by measuring the depth. Like counting rings of a tree.