The age of the Earth is approximately:

Correct answer: 4.5 billion years. The Earth is about 4.5 billion years old.

Background: Scientists measure the age by dating very old rocks and meteorites.

• 1.5 billion years: 1.5 billion years is too young.
• 3.5 billion years: 3.5 billion years is about when early life appeared.
• 10 billion years: 10 billion years is older than the Earth.

Did you know? The universe is about 13.8 billion years old.

Memory trick: Earth ≈ 4.5 billion years.