I've been hearing and reading about that solar flare in 2012 that could have sent us back to the 18th century, by causing huge geomagnetic storms which would have prevented (every?) electricity-based devices from working correctly. They say the economic cost of this disaster would have been something like 2 trillion USD.

I found this scenario very inspiring, and I have some questions about it.

  1. How far would this regression go if planet Earth was hit by such a solar flare? Would it be just like in the movie "The day the earth stood still"? Could we still find a way to create electrical energy in these conditions? Would we be forced to come back to steam power or something else? Would this actually be our major problem?

  2. Now suppose that we could anticipate such a cataclysm and know its length in advance (say two whole weeks). What would be the most likely security measures we could take to prevent most of the potential material and economical damages?

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    $\begingroup$ Don't have time to write a full answer right now, but if you google EMP (Electro Magnetic Pulse) weapons, you might get some useful material on "hardening" and "shielding" of electronics, as well as the after effects of such a cataclysm. If you have time to do some light reading, S.M. Sterling's Change novels explore life in a post-electric world. $\endgroup$ Dec 18, 2014 at 15:34

5 Answers 5


Our power grids and satellites would be heavily damaged or destroyed.

However, any electronics not plugged into the wall or connected via a very good surge protector would, for the most part, be fine. If the magnetic flux was high enough to induce currents in handheld electronics, computers, or cars, enough to destroy them, we'd have other things to be worried about. I'm most familiar with the US power grid, which is comprised of three sub-grids. Each of the sub grids is, electrically, one piece. The transmission lines (power lines) act as a massive array of antennas. As the magnetic storm hits, these antenna couple in the energy and we get a massive spike. This is what destroys most of the devices plugged into the wall and, depending, the transformers on the residential distribution hubs.

Anyone who says that anything electronic would be destroyed has watched too much television and/or is not considering the stupendous amount of energy that would require.

The higher latitudes would actually be the most affected. In fact, equatorial power grids may fair the storm without excessive damage. This is because of the orientation of Earth's magnetic field. The poles will experience a massive amount of magnetic flux, this is measured in Teslas.

So Alaska will be screwed, but the Aurora's will be absolutely stunning. We'll even get some nice Auroras at much lower latitudes.

Pro Tip: If you live in California, and the sky is on fire with green dancing ribbons, drop what you're doing and buy bottled water and a generator.

enter image description here Source

The satellites, being less protected by Earth's magnetic field, get hit much harder. Though some may survive, because engineers know that they're less protected and so they built some protection in.

So, the destruction would be devastating, no more Netflix for a long time. Unfortunately, you won't be able to make a FWP meme about it for quite a while.

You can protect your stuff.

As mentioned in the comments, you can protect yourself in the same way you'd protect against an EMP. Personally, I'd just use a surge protector and keep emergency supplies. But if you want to go to the extreme you can build a Faraday cage to place sensitive electronics in. Just don't bother trying to build one for your house unless you're also going to isolate all the electrical connections coming into the house.

So, steam power will work, but your TV won't.


First of all, even at the time those with a background in this stuff knew already that the "threat" posed by that solar storm was all hype. However, the theory is sound, and a big enough solar storm could potentially disrupt electronics.


Little-to-none, really. Solar storms are very hard to predict, and when an eruption does occur that could have such catastrophic effects, it moves far faster then we can see it and then brace for it. The only defense we can mount is to prepare for such an event before it occurs.

Edit: Twelfth points out in the comments that we're actually far better these days at detecting and predicting these types of events. I admit I haven't looked into the state of affairs on this point in quite some time, so the preceding paragraph is quite probably quite obsolete.

Immediate Effects:

All unshielded electronics are irreparably "fried" as the EMP caused by the magnetic storms induces massive currents in every unshielded conductor, overloaded and literally burning up sensitive electronics. This means computers, cell phones, cars, televisions -- just about anything and everything that you have to plug in or stick a battery in.

Similar induced currents disrupt and in many cases destroy the infrastructure for generating and distributing electricity. Not the wires themselves, mind you, but the transformers that make it all work will be blowing left and right, not to mention all the computers that control the generators themselves (which, being basically big conductors, may also face damaging inductive currents as well).

Also, don't listen to that horrid movie Broken Arrow -- turning your electronics off will not prevent the EMP from destroying them. It may reduce the overall current and potentially preserve a few components, but really it's the induced current itself that causes the damage, not the combination of the regular current with the induced one.

Note that shielding electronics against EMP is actually rather simple, albeit not exactly cheap and, thus, not extensively done. But anything shielded (much -- but not all, not by a long shot! -- of the military's hardware is shielded, and with the much over-hyped fears of terrorism these days some of our civilian infrastructure has been shielded as well) will survive more-or-less unscathed. Don't underestimate the ability of panicked people to destroy what the storm leaves untouched, though!


There's no problem generating electricity again after the storm passes (the storm itself will be shorter-lived than the widespread panic and civil unrest it causes). At least, not with generation itself -- there's a lot of work ahead to restore modern-era generators, since they're computer controlled and, as mentioned above, computers have been destroyed. Relatively easy to retrofit them to be run manually in the meantime, however. We'll be able to rebuild, though, and we won't really be thrown back into the 18th century -- it might look somewhat like it at first, but thanks to those not-quite-obsolete things called "libraries" most knowledge will remain intact and, with that, we'll be able to get ourselves back to 21st-century tech in a much shorter time frame.

That's not to say that we wouldn't regress in many other ways, but your question seems to be asking about the technological impacts so I'll restrict my answer to those as well.

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    $\begingroup$ @edA-qamort-ora-y Yes, it does. And absolutely we would lose a lot of information -- but not all. Non-magnetic media (DVDs, CDs, books, etc.) would be intact, though, so we wouldn't be starting from scratch, which was my main point. $\endgroup$
    – Kromey
    Dec 18, 2014 at 19:08
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    $\begingroup$ @Kromey - we are getting better at detection then you imply here...the online world that once watched nothing but hurricanes has heavily changed it's focus to the sun. Suspicious Observers is one such group that watches sunspots and looks for the prewarnings of these flarings. A flare that would take earth out to this degree would be proceeded by some pretty heavy sunspot activity that we are getting better at recognizing. $\endgroup$
    – Twelfth
    Dec 18, 2014 at 19:23
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    $\begingroup$ Just to give a timescale reference (besides "little-to-none"), the 2012 CME took around ~18 hours to travel from the Sun to the Earth. So, assuming people are paying attention to the Sun, that's about the minimum amount of warning you would get. $\endgroup$ Dec 18, 2014 at 19:48
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    $\begingroup$ @Samuel Basic physics. A disruption in the magnetic field -- what we're talking about here -- will induce current in conductors. A strong enough disruption will induce more current than they can handle; this generates enough heat to literally burn them up (hence "fried"). Since the question was about an event that "sets us back" to the 18th century, I answered under that assumption. We're not simply talking about surges in the power grid, though those will happen as well; induction in the conductors within electronics themselves will directly fry even disconnected and powered-down devices. $\endgroup$
    – Kromey
    Dec 18, 2014 at 21:07
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    $\begingroup$ Actually I think the aftershock is severely underrepresented in this answer. Power down means no cooling of foods, no heating for everyone not running a manual oven. Automobiles down means no trucks, means no continued supply of foodstuffs. We're looking at widespread looting, followed by a severe case of famine in all the more developed countries where people basically expect to be fed by the grocery store... $\endgroup$
    – DevSolar
    Dec 19, 2014 at 12:17

When humans started laying conductors hundreds of miles long they discovered induction from solar activity. The news was self-delivering as telegraph offices burst into flame.

Nominally, power lines should accommodate it by having isolation points that prevent induction on such a planetary scale, and the "high tension" wires normally carry orders of magnitude more energy.

The problems, IIRC, are two: The grid is chaotic and maintained as a series of mismatched patches, what we call a Stovepipe (anti) pattern. It's pushed past design limits because it works, but that means it erodes the emergency capacity, and it's subject to cascade failures.

Second, the true extent of the solar activity was not known. How bad can they get, on rare occasion?

I recall that the main issue for recovering is a particular component that doesn't have enough spares nor the capacity to produce them quickly. It's a problem of fragility caused by risky single points of failure, not that everything gets trashed.

(FWIW, I have my own 10kW solar generator. Post-flare party at my place, pot luck!)

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    $\begingroup$ Solar generator under a solar flare ... even if it's unplugged when the flare its, would it not be likely to be overloaded anyway ? $\endgroup$
    – Hoki
    Dec 19, 2014 at 11:54
  • $\begingroup$ No, it's not a miles-long conductor. Furthermore, the inverters are transformerless. $\endgroup$
    – JDługosz
    Dec 19, 2014 at 18:33

It seems to me we've become very complacent and dependent on reliable electronic devices and information storage.

With most electronic devices getting destroyed, many vehicles and especially aircraft will suddenly be in trouble. Hospitals will be in trouble, both for existing patients and then for the many new patients who will arrive shortly. Power grids and infrastructure will be in trouble. Supply transportation will be in trouble. Modern cities will be in trouble because of their high dependence on supplies which now may be nearly impossible to deliver.

I would like to feel like I confidently know how much information would be able to survive strong induced currents. I think optical (especially ink-based) disks would survive, and disk platters themselves would survive, but most reading devices for both would be fried, and the information and ability to build new readers for them might be practically lost. The severity of the pulse would matter. Hopefully optical disks and some hard drive information will eventually be recoverable. What information and what technology survives could be significant.

I would also like to know how good military shielding of electronics from EMP is - will enough EMP overcome any shielding? I don't know.

And of course, a very similar crisis can occur from atmospheric nuclear weapons detonation - one detonation can fry electronics in a very wide region, and this has been a known tactic for 50 or more years, so it's quite conceivable that at some point humans will be dysfunctional enough to do this to themselves, thinking they are getting at their enemies.


Consider also that a good part of the economy would go splat. Anything that depends on regular, reliable connectivity (from Facebook to Amazon) is going to tank, because of broken data centers, broken telecom infrastructure and broken devices at the customer and supplier end.

Of course this would affect different countries/lifestyle to a very different grade.


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