This is actually an active topic of research and debate, and both NASA and ESA have independent and complementary panels to assess the worst case scenario. There are several precedents that indicate very real risks to technology and health.
The first 'space weather' (as the field is called) event recorded was in 1859 when Lord Carrington was taking his daily sunspot images at home with his personal projection telescope. He noticed a couple of bright ribbons appear, grow to be very bright, and then subside over about 5 mins. He published this observation in the Philosophical Transactions of the Royal Society, and it was at this stage the people started to link the various disturbances that had been observed on Earth to the solar event. There's a well written piece on NASA's site here:
http://science.nasa.gov/science-news/sc ... gtonflare/
which mentions aurorae visible as far south as the the NH tropics, and I've heard it said the same was seen in the SH tropics too (aurarae are rarely this symmetrical, it's almost always stronger in either the N or S polar region). Interestingly though, even back then some technological systems - here, the telegraph - was vulnerable. It's not mentioned here, but ships at high N and S latitudes had touble navigating due to compasses going haywire. More recent high-profile events are also covered, specifically in 1972 (telephone networks including transatlantic cables), 1989 (power substation loss and subsequent grid collapse) and 2005 (GPS navigation system loss).
It's likely that as well as being the first solar flare directly observed, it was also the most powerful - as the article explains, it's likely to have been the most intense flare of the past 500 years, and possibly more. So what could we expect if the next 'once in a millennium event' happens during this cycle when we're completely dependent on technology? There's another NASA article that covers this here:
http://science.nasa.gov/science-news/sc ... rediction/
and concludes with an estimate of costs >$1Tn and a 4+year recovery. The types of problem that leads to costs like that are the ones already experienced in less powerful events, so you have to start thinking along the lines of, "If a measly 1989 flare can knock out one transformer, then how many would a Carrington event take out?" and that's when the costs soar. The problem is, where to draw the line? It is possible to over-engineer these systems to cope with all eventualities, but that's terribly expensive too, and there's no point designing something you want to work for 15 years (that's the lifetime of the Galileo satellite) to cope with a once-in-a millennium event. So you design them to cope with 95% (typically) and have to have fallbacks available in case something worse does happen.
Anyway, for all this talk about The Big One in May 2013, there's no reason to
expect it to be a real ball-breaker. The next sunspot maximum is predicted to be pretty low (see the second article) although the fact that it coincides with a magnetic maximum
could make it a bit more tricky. Predicting the date and peak height of the cycle maximum is one thing, predicting the extent and severity of the individual events is entirely different. A lot is being made of the fact that the next maximum is predicted to be the same peak height as the cycle of 1859, but the probability is that this will be no more than coincidental. Look at the long time-series plot of sunspot number and there are several that peak around that level, and they don't all have superflares. Likewise the speculation that it could be a rough ride because it comes right after a prolonged minimum has no solid basis in either theory or historical record.
The fact is that like scientists in all disciplines, we need headlines from time to time to keep us relevent, and to my mind this is a nice way of raising the profile without generating hysteria (just mild hyperbole). I know the folks quoted in both these articles and the others who've cropped up in the Telegraph etc recently, and they all understand the value of a good headline. It's interesting to read articles like these again and see how many times the word 'could' is used ... ;-)
Cheers, Gareth.
Dr S":27fir8uw said:
Thanks for that, really interesting.
Can you tell us what to expect in May 2013 when we get the big one?
Si
