The notion that the Earth's atmosphere would rapidly be stripped away if the magnetic field vanished is very unlikely. There's a lot of complex chemistry and p

The notion that the Earth's atmosphere would rapidly be stripped away if the magnetic field vanished is very unlikely. There's a lot of complex chemistry and physics that control rates of atmospheric escape from planets - but here's an accessible overview: https://www.scientificamerican.com/article/how-planets-lose-their-atmospheres/ https://www.scientificamerican.com/article/how-planets-lose-... Basically the intensity of sunlight (distance from the Sun) relative to the gravitational field of the planet are the main factors. Magnetic fields play a minor role at best, by trapping charged water-sourced hydrogen ions - but those ions can easily lose their charge and then escape to space: > "An important process for hydrogen loss is “charge exchange”, which probably accounts for about 40 percent of the present escape of hydrogen from Earth and most of the hydrogen escape from Venus. Solar radiation creates electrons and positively charged ions in upper atmospheres by tearing electrons off atoms or molecules. Subsequently, charge attraction and repulsion in collisions accelerates ions. On Earth, the magnetic field traps ions, but a fast hydrogen ion can collide with a neutral hydrogen atom and capture its electron. In this exchange of charge, fast ions turn into escaping neutral atoms." The primary reason Earth doesn't see high rates of hydrogen formation from water and subsequent loss in the upper atmosphere is that the surface temperatures are low enough such that the stratosphere remains very dry. On Mars, due to lower gravity, this stratification should have been less, leading to higher rates of water loss from the upper atmosphere.