Instead, the radiocarbon atoms in their bodies slowly decay away, so the ratio of carbon-14 atoms to regular carbon atoms will steadily decrease over time (Figure 1c).Let’s suppose we find a mammoth’s skull and we want to date it to determine how long ago it lived.
By comparing the surviving amount of carbon-14 to the original amount, scientists can calculate how long ago the animal died.
Since the atmosphere is composed of about 78% nitrogen,2 a lot of radiocarbon atoms are produced—in total about 16.5 pounds (7.5 kg) per year.
The radiocarbon half-life or decay rate has been determined at 5,730 years.
Next comes the question of how scientists use this knowledge to date things.
These excited neutrons then collide with nitrogen atoms in the atmosphere, changing them into radioactive carbon-14 atoms.
CARBON-14 IS ABSORBED (Figure 1b): Plants absorb this carbon-14 during photosynthesis.
Although many people think radiocarbon dating is used to date rocks, it is limited to dating things that contain the element carbon and were once alive (like fossils).
Rb)—are not being formed on earth, as far as we know.
These rapidly combine with oxygen atoms (the second most abundant element in the atmosphere, at 21%) to form carbon dioxide (CO).
This carbon dioxide, now radioactive with carbon-14, is otherwise chemically indistinguishable from the normal carbon dioxide in the atmosphere, which is slightly lighter because it contains normal carbon-12.
Thus it appears that God probably created those elements when He made the original earth.