Monday, March 12, 2012

Solar Flares - Can We Get A Grip?

I assume that everyone saw last weeks' dire warnings about a pair of X-class flares and the hand wringing about all the damage they could do?  One of those two flares was a respectable X5.4, and while the chances of Really Bad Things from an X5.4 are slightly above zero, there was still way too much hand wringing over it.  The really bad part was that they made a fuss over an M-8 class flare over the weekend.

Guys, I don't quite know the best way to put this in perspective, but most of us can damage the grid more with a fart than a M-8 flare ever could. 

In a way, I've covered this before, with my August 2010 post, "Yo, NASA! Can We Knock Off the Solar Storm Scare Tactics?" but it's worth talking about again.  Solar flares are (obviously) a real phenomenon, and the Coronal Mass Ejections (CMEs) that accompany the big ones are a real concern for satellite operators.  A really big CME could damage the power grid.  But "a flare" is not the same as "a really big CME" .  Back in that August, '10 post, I noted;
See, solar flares vary over orders of magnitude in size.  The smallest go from C1 to C10.  Next up, M class flares also go from a 1 to a 10.  Finally, the biggest flares are X class or X-ray flares.  There's no top to that scale, but in the peak of the last solar cycle, back around 2003, X class flares were hitting every month.  An X10 flare hitting directly can make auroras visible in the southern US.  A monumental flare in 2003 made them visible in north central Florida.  I have heard a big flare in the previous cycle (1990s) caused an aurora visible in the Caribbean.
The strengths of these solar events vary like all natural processes, with weaker ones much more common than strong ones.  A flare strong enough to do the damage people worry about is a very rare event .  Let me quote from that 2010 post:
Is it possible for a solar CME to do the things they talk about? Absolutely. How likely? There has been one CME since 1900 that damaged parts of the grid (it shut down power in Quebec) and that was in the last peak of the 1990s (1996?).  It's not precise to say expect it to happen once in a hundred years, but probably close enough for discussion.  If you own a satellite, you can shut it down when a big CME is coming because you see the flare and ejection when they happen (ignoring that the light takes 8 minutes to get here from the sun) while the particles from the CME take a couple of days to get here.   
Again, during the peak days of the last cycle, in 2003, we were getting X-class flares a few times every month, and the grid was fine, wasn't it?  There was a super flare in November of 2003 that was genuinely scary and the kind of flare to worry about.  The biggest flare seen since the satellite age started, it was classed as X28 in retrospect - only because it saturated the X-ray detectors on the satellites and they couldn't measure it properly.  Why didn't it harm us? Because it was on the limb of the sun and the CME went 90 degrees to our direction.  So not only does this extremely rare event need to happen, but it has to be pointed at Earth - basically perfectly centered on the sun from where we view.
The mother of all CMEs (that we know of) is called the Carrington Event, and occurred in 1859.  It was such a bright flash that legend says people noticed the daylight get brighter.  Auroras were reported in Cuba and Hawaii.  This was in the early days of wired telegraphy and the "grid", such as it was, was damaged.  There were reports of telegraph keys arc'ing and even fires being set.  I remember reading an unlucky telegrapher was electrocuted by his key.   While we can estimate the strength of that flare/CME by other means, it's fair to call it the strongest CME to hit Earth in the last 150 years.  So what do you think the chances of another one are?  According to someone quoted by Reason, the chances of another one between now and 2020 are 12% - 1 in 8.  So something that hasn't happened since 1859, through all those solar cycles, including the strongest cycle on record, has a 1 in 8 chance of happening now?  In this weak, erratic solar peak - in the next 8 years?  Really, dude, you don't have to say between now and 2020.  The next 2 or 3 years should locate the peak pretty well.

I don't buy it.

Wake me up when an X10 flare and CME is on the way.  I wanna see the auroras.  Until then, keep your hype to yourself. 


2 comments:

Anonymous said...

I blame global warming. (It makes about as much sense....)

drjim said...

Thanks for putting this in penrspective.
I was goig to post about it, but couldn't possibly have said it better!