If not carbon dating then what
However, radioisotope dating may not work so well in the future.
For example, say a fossil is found that has 35% carbon 14 compared to the living sample. We can use a formula for carbon 14 dating to find the answer.
Other useful radioisotopes for radioactive dating include Uranium -235 (half-life = 704 million years), Uranium -238 (half-life = 4.5 billion years), Thorium-232 (half-life = 14 billion years) and Rubidium-87 (half-life = 49 billion years).
The use of various radioisotopes allows the dating of biological and geological samples with a high degree of accuracy.
Where t is the age of the fossil (or the date of death) and ln() is the natural logarithm function.
If the fossil has 35% of its carbon 14 still, then we can substitute values into our equation.