Question: how old is the earth

Maxime Savatier answered on 12 Nov 2019:

4.54 billions years old !

The oldest piece of rock found on earth was younger, 4.3 billions years old (a zircon in Autralia). But then, the rocks brought back from the moon by the space missions and the meteorites found so far formed 4.4-4.5 billions years ago. One of these meteorites could be dated with more accuracy, and formed between 4.53-4.58 billions years ago. This is thought to be the period when the elements forming earth came together and cooled down to form a rocky planet, and this is where this number come from:)