How do scientists know how old the Earth is?

It’s a question humans have grappled with for centuries – how old is the Earth?

For a long time in the Western world, the history of our planet and species was derived word-for-word from the Christian Bible.

Back in 1642, John Lightfoot, an English clergyman, calculated what he thought to be the exact date of the creation of the universe: September 17, 3928 BC. He arrived at this conclusion by counting backwards through the epic genealogies recorded in the Bible

According to science, however, the Earth is a much older rock. It’s been labouring around the sun for 4.54 billion years, in fact, which we often round down to 4.5 billion. 

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