Question: how old is the earth

Laurent Dupays answered on 5 Jun 2018:

4.543 billion years, this is really old!

How do I know? I googled it 🙂

I am a biologist and not a geologist. Indeed, a geologist answers questions about how earth came to have its present shape and form. Geologists find important materials in Earth’s crust, such as oil. They can also predict earthquakes and other natural hazards. And obviously they can tell you how old is Earth!