Carbon 14 dating dinosaur fossils
When paleontologist Mary Schweitzer found soft tissue in a Tyrannosaurus rex fossil, her discovery raised an obvious question -- how the tissue could have survived so long?The bone was 68 million years old, and conventional wisdom about fossilization is that all soft tissue, from blood to brains, decomposes.Once all the parents have become daughters, there's no more basis for comparison between the two isotopes.Scientists can't tell whether the clock ran down a few days or millions of years ago.This means that isotopes with a short half-life won't work to date dinosaur bones.The short half-life is only part of the problem when dating dinosaur bones -- researchers also have to find enough of the parent and daughter atoms to measure.
If, however, there are too many or too few neutrons, the atom is unstable, and it sheds particles until its nucleus reaches a stable state.
Radiometric dating relies on the properties of isotopes.
These are chemical elements, like carbon or uranium, that are identical except for one key feature -- the number of neutrons in their nucleus.
But you can predict how long it will take a large group of atoms to decay.
The element's half-life is the amount of time it takes for half the parent atoms in a sample to become daughters.