A G1-class geomagnetic storm is underway today (19 February 2020) as the Earth enters a minor stream of solar wind. Even before the solar wind arrived, Earth’s magnetic field was humming with energy because of a crack that opened for over 8 hours yesterday; solar wind poured in, setting the stage for today’s storm. A G1 storm can mildly impact on satellite operation and power grids.
The Earth is surrounded by a magnetic force field, a bubble in space called “the magnetosphere”, which is tens of thousands of kilometres wide. It’s a far-flung part of the same planetary magnetic field that deflects compass needles here on Earth’s surface. And it’s important. The magnetosphere acts as a shield that protects us from solar storms.