🧲 What if Earth's magnetic field disappeared?
More radiation at the surface and slowly stripping atmosphere — over geological time.
The science
Our magnetosphere deflects most of the solar wind. Without it, charged particles would reach the upper atmosphere directly: auroras could appear worldwide, radiation exposure at the surface would rise, and the solar wind could strip atmosphere molecule by molecule — as is thought to have happened on Mars.
Immediate consequences (modelled)
Compasses useless; auroras at all latitudes; more satellite and power-grid disruption from solar storms.
Possible long-term consequences (hypotheses)
Gradual atmospheric loss over hundreds of millions of years — not an overnight catastrophe.
Assumptions: Field loss is total and permanent; atmosphere thickness initially unchanged.
Limitations: Does not model climate, geology, biology or engineering in full detail.
Reference: NASA magnetosphere research; Mars MAVEN results