Nearly every day I hear from at least one person who thinks I am an idiot. Typically they are complaining about something I wrote months or even years before, so I often confirm my idiocy by not even remembering what has them so upset. This week, however, I was contacted by an upset reader who may well have a good point, so let’s reconsider for a moment the security of Global Positioning System — GPS.

I wrote more than a year ago that a Government Accountability Office report was overblown, claiming a 20 percent chance of the GPS system going down in the next few years because the U. S. Air Force can’t launch new satellites fast enough to replace those that are dying. I just didn’t see this as a big deal and said so.

This week, however, I heard from a retired communication engineer who lectured me at great length about my various failings as a human being, but in the process made a couple points that I have to concede are correct. The first of these is that the GPS system is vulnerable to a catastrophic solar storm and we have reason to believe such a storm might be coming between now and 2013.

Or not.

That’s the way it is with these things, you know. A lot could happen, but nothing must happen. Still, his argument was sobering. Basically we are headed toward a peak of sunspot activity in 2012 or so that could well trigger a Coronal Mass Ejection (CME) that could take out half or more of all geosynchronous satellites, not just GPS. No more satellite navigation, no more cable TV.

Here, simply to infuriate space scientists everywhere, is my simplistic explanation of a CME. Remember how in Ghostbusters they weren’t supposed to allow the beams from their nuclear-powered ghost guns to cross? Well there are similar magnetic beams that emerge from sunspots and solar flares and if two of those with opposite polarities should happen to cross, a magnetic burp follows, ejecting millions of tons of magnetically charged material from the Sun’s corona headed toward the Earth at speeds up to two million miles-per-hour. That’s a Coronal Mass Ejection or CME.

CME’s come in various sizes and velocities. CME’s aren’t intrinsically aimed at the Earth and could just as easily dissipate into empty space. Many CME’s don’t even make it as far as the Earth. But if conditions are right, CME’s can do a lot of damage. A CME hit Quebec in 1989 causing a nine-hour blackout and $4.3 billion in damages to the Canadian power grid. The mother of all CME’s in 1859 took down every telegraph in the world, causing arcing, fires, and melted wires in the equipment. Imagine what something like that would do to your PC or cellphone!

“Something like that” in this case means a very quick release of energy comparable to 100 billion Hiroshima atomic bombs. It would fry satellites, overload power grids, destroy all our computers, and possibly put the lights out for most of us for months simply because it would take at least that long to replace all the blown utility transformers.

Interestingly, CME’s have impact not only on that part of the Earth facing the Sun, but also on the backside where the Earth’s magnetic field is stretched and then rebounds releasing terawatts of destructive energy. So the entire GPS constellation including spare satellites is endangered.

Okay, against a threat of that scope and grandeur I’ll accept that the GPS system is vulnerable, which brings me to the guy’s second point: the only viable alternative to GPS that is ground-based is the old LORAN system, which was recently switched-off for good.

IF we really believe the GPS system is vulnerable and there is even a remote chance of these actions coming to pass, then shutting-down LORAN was a mistake. The U. S. Coast Guard shut down the LORAN system to save $36 million per year in operating costs, which to my critic this week seems a false economy. It might be better, he says, to actually add LORAN capability to all GPS-enabled devices, since LORAN works indoors and in burning buildings, too, where GPS doesn’t.

I stand corrected.