Because, your body ages everyday, so ,,its like a clock ,tik, tik :)
Absolute age is the age of a rock as determined by the measurement of radioactive decay from the time of the rock's formation.
The basic idea is to measure the amount of the radioactive isotope, and of one or more of its decay products. The older the rock, the larger the percentage of the original isotope that decayed - so the ratio between the original isotope and the decay product changes over time.
Radiometric dating is possible because the rates of decay of radioactive isotopes are constant and predictable over time. By measuring the amount of remaining parent and daughter isotopes in a sample, scientists can determine the age of the sample.
If radioactive decay rates were not constant, the passage of time inferred from radiometric dating would be inaccurate. Changes in decay rates would affect the ratio of parent to daughter isotopes used in dating, leading to flawed age calculations. The fundamental assumption of radiometric dating is that decay rates remain constant over time.
Age.
They are determining the age of the rocks. Radioactive elements decay over time, so the composition of a rock can indicate when that particular strata was formed.
After puberty and before decay with age, height and age are not related.
Radioactive or radiometric dating allows us to estimate the Earth's age by giving us the actual age of rock within a range of several million years. Radiometric dating is based on the scientific law of radioactive decay and the half-life of radioactive elements. Uranium and some other elements decay into lead over time at a specific rate. Knowing the content of these elements in the makeup of a rock allows its age to be calculated. Currently, the oldest rocks of Earth origin are estimated to be over 4 billion years old.
Because radioactive decay happens at a constant rate. Once you figure out the rate of decay, called the half life, you can date stuff.
"The radioactive decay of certain unstable isotopes is used to calculate the age of objects."
By radioactive decay process.
by know of initial mass of the earth and mass of the earth in this time we can find mass decay of the earth and by the formula of E=MC2 we can find the energy of the earth and when we have the energy by formula E=E0e(it) we can find t that is the time