https://thenextweb.com/syndication/2020/10/17/why-the-moons-early-magnetic-field-might-be-responsible-for-life-on-earth/

The habitability of a planet depends on many factors. One is the existence of a strong and long-lived magnetic field. These fields are generated thousands of kilometers below the planet’s surface in its liquid core and extend far into space – shielding the atmosphere from harmful solar radiation.

Without a strong magnetic field, a planet struggles to hang on to a breathable atmosphere – which is bad news for life as we know it. A new study, published in Science Advances, suggests that the Moon’s now extinct magnetic field may have helped protect our planet’s atmosphere as life was forming around 4 billion years ago.