When I mentioned cosmic rays in my article last week, I actually had to restrain myself from taking a big tangent to talk about the effects of stronger rays on earth. These stronger rays are often referred to as “solar storms” or the more accurately, “coronal mass ejections”. These ejections are essentially concentrated amounts of matter (protons and electrons) as well as electromagnetic radiation. While they are generally associated with other solar activity such as solar flares and sunspots, the relationship isn’t yet fully understood.
Our sun is always producing these CMEs. Depending on where the sun is in its solar cycle, there can be up to a few CMEs per day or as few as one CME every week. A CME can be produced basically anywhere on the sun’s surface so the odds that one will shoot out and directly hit earth are generally pretty low. However, it has happened, and despite our magnetosphere shield, the effects on the surface (especially to modern technology and infrastructure) can be severe.
There have been several large CMEs that have impacted earth in recent years, but the largest ever recorded occurred in 1859. To a mostly non-electrified society, a CME poses relatively little risk. The most obvious indication that something has occurred would be aurorae at latitudes much closer to the equator than normal. As I discussed last week, aurorae are the result of high energy particles colliding with particles in the atmosphere. This energizes the particles and can cause luminescence.
The effects of such events are wide ranging. For a society like ours that has a lot more electric gizmos, the effects can even be dangerous. The earth’s magnetic field and atmosphere shield the surface from the most harmful effects, but the effects become stronger the higher up you go. This makes satellites and aircraft particularly vulnerable. The high energy electromagnetic radiation can induce increased voltages in electrical equipment that can cause failures or even fires. During these CMEs communication that relies on satellites can be disrupted. Electrical grids with their miles of transmission wires act like antennae for the electromagnetic radiation. This can easily cause them to overload and destroy key components like transformers. If a CME the size of the 1859 event hit earth today, the damage would likely in the billions of dollars.
There isn’t much that can be done to protect equipment from these electromagnetic storms, but Faraday cages can offer some protection. A Faraday cage is basically just a metal cage into which you place electronics to be shielded from electromagnetic radiation. If the cage wires are thick enough, and the holes smaller than the electromagnetic radiation wavelength, it will block that radiation from getting inside. If you’ve ever tried to use a cell phone in an elevator without success, this is why. The cell phone is transmitting electromagnetic radiation and the elevator is an approximate metal cage that absorbs the radiation before it can escape.
So far we haven’t been faced with a CME with the same strength as the one that occurred in 1859, though they do still happen. In July 2012 there was an event that would’ve rivaled the 1859 event but it missed earth. Smaller events do occur all the time, however, and can interrupt communications and electrical grids. All things equal, I think I’ll take a blizzard over a big solar storm.