Explanation:

The Van Allen belts are a collection of charged particles, gathered in place by Earth’s magnetic field. Most of the particles that form the belts are thought to come from solar wind and other particles by cosmic rays. By trapping the solar wind, the magnetic field deflects those energetic particles and protects the Earth's atmosphere from destruction. Presumably the magnetic field of the Earth is generated by a dynamo effect that involves its rotation. If the Earth stopped rotating, its magnetic field would no longer be regenerated and it would decay away to some low, residual value due to the very small component which is ‘fossilized’ in its iron-rich rocks. There would be no more 'northern lights' and the Van Allen radiation belts would probably vanish, as would our protection from cosmic rays and other high-energy particles. This is a significant biohazard.