The numbers
The second tile describes an event considered the benchmark for strength. At the time, auroras were seen nearly at the equator, while telegraph lines continued transmitting messages even with their batteries disconnected - current was induced in the wires themselves.
The third tile shows what this means today. Induced currents flow through long conductors - power lines, pipelines and rails - and overload transformers, which are not designed to handle direct current.
What happens, step by step
An eruption. The Sun ejects a cloud of matter. It takes anywhere from several hours to several days to reach Earth.
A field encounter. The magnetic field compresses and reconfigures. Some particles enter along the field lines toward the poles.
The aurora. The particles collide with gases in the upper atmosphere, making them glow: oxygen produces green and red, while nitrogen produces blue.
Induced currents. Changes in the field induce current in long conductors on the ground. This is the practical danger.
The first step provides the only protection that works - time. Satellites can be switched to safe mode, planes can be diverted from polar routes, and grid operators can reduce the load on transformers.
Satellites are also affected directly. The upper atmosphere expands during a storm, causing low-orbit spacecraft to experience more drag and lose altitude; several launches have already been lost for this reason.
Satellite navigation also becomes less accurate: the signal passes through disturbed layers of the atmosphere and arrives with a delay. You will not notice this on your phone, but it can be significant for aviation and surveying.
Finish reading in the Miqo app
1 more minute, then a quiz at the end. Find it under “Space → The Sun”
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Sources
- Geomagnetic storms caused by solar-matter eruptions lead to induced currents in extended conductors, increased drag on low-orbit satellites and reduced satellite-navigation accuracy
- the 1859 event is considered the strongest documented event