Given the following information, the older the object the less accurate this method of dating becomes. How can scientists say that the Earth is billions years old?

Question

Chemical analysis used to determine the age of organic materials based on their content of the radioisotope carbon-14 is believed to be reliable up to 40,000 years

Emma Arvizu · Accepted Answer

Because it is merely a hypothesis based off strong evidence.

In this case, scientists know that carbon 12 has a half life of about 5730 years, which allows them to predict that it will accurately show time elapsed up to 40,000 years. However, this is all based on an estimate; perhaps it doesn't and advances in the field of radioactive decay over the next few years will show a different, more precise value, but for now, scientists have to make do with what they have. This is the wonderful thing about science: we don't always have a way to prove what we say (and most of the time don't).

Logan Allen · Answer

undefined Scientists can determine the age of the Earth using various methods, such as radiometric dating, which measures the decay of radioactive isotopes in rocks. While radiometric dating becomes less accurate for older objects, scientists can use multiple isotopic systems and cross-checking methods to arrive at a reliable estimate of the Earth's age, which is around 4.5 billion years.