# ch4

the Earth was created at midday on October 23, 4004 BCE.

Marie curie discovered, Certain elements release energy without changing size or shape.

Rutherford discovered radioactive elements disintegrate in other elements like uranium-235 into lead-207

Decay happens at same speed

Half life is used for estimating age of something

Claire Cameron Patterson discovered precise dating method that estimated earth to be 4.55 billion years old +/- 70million years
