Newton's estimate of the age of the Earth?

Question

I was reading many articles about estimates of the age of the Earth throughout the ages. I was dumbfounded when I read that Newton, arguably one of the greatest scientists ever to have ‘calculated’ the age of the earth, estimated that the Earth was created in 4000 BCE. Johannes Kepler arrived at a similar result. Which methods did these scientists use to arrive at such conclusions?

Answer 1

Isaac Newton used rigid body physical mechanics to determine this age. I'm not sure of the exact calculation. I do know however he did not account for the many rigid plates that are in convective motion on Earth. But his biggest miscalculation was the later discovery of radioactive decay. Those elements in rock decay over time into new isotopes and elements. This reaction releases a lot of heat (energy) keeping the Earth warm and hence pushing back the age of the Earth. Later on, Werner Heisenberg observed this reaction in a laboratory and was hired under Hitler to harness this reaction into a weapon. Heisenberg failed. However, this reaction was harnessed by physicist Robert J. Oppenheimer into the atomic bomb during the Manhatten project.