The Earth has had a magnetic field for the last ___ years.

Question

Quizplus · Accepted Answer

Scientists believe that the Earth's magnetic field has been present for at least 3.5 billion years based on evidence found in ancient rocks. While there is some evidence of a magnetic field existing up to 5 million years ago, it is thought to have been sporadic and not as continuous as the present-day field. The idea that the Earth's magnetic field has been present for 1 billion years is unsupported by current scientific evidence.

The Earth Has Had a Magnetic Field for the Last