How radiometric dating supports the theory of evolution
Many independent measurements have established that the Earth and the universe are billions of years old.Geologists have found annual layers in ice that are easily counted to multiple tens of thousands of years, and when combined with radio isotope dating, we find hundreds of thousands of years of ice layers.Once the rock hardens, however, all the Argon-40 is trapped in the sample, giving us an accurate record of how much Potassium-40 has decayed since that time.So, if we find a rock with equal parts Potassium-40 and Argon-40, we know that half the Potassium-40 has decayed into Argon-40, and that the rock hardened 1.3 billion years ago.This conclusion is not based on just one measurement or one calculation, but on many types of evidence.Here we will describe just two types of evidence for an old Earth and two types of evidence for an old universe; more types can be found under further reading.
Astronomers and geologists have determined that the universe and Earth are billions of years old.
Using the known rate of change in radio-active elements (radiometric dating), some Earth rocks have been shown to be billions of years old, while the oldest solar system rocks are dated at 4.6 billion years.
Astronomers use the distance to galaxies and the speed of light to calculate that the light has been traveling for billions of years.
Meteorites are rocks from the solar system that have fallen to Earth recently and haven’t suffered much erosion.
Their pristine interiors give an age that dates back to their formation at the beginning of the solar system.