Seeing as my spare time has been spent reading up about stars and stellar phenomena, this seemed appropriate. NASA’s photo of the day (in negative here) is of the Solar cycle. Over a period of roughly 11 years, the Sun goes from a tranquil bringer of daylight to a rampaging x-ray spewing beast. It varies, anywhere between 9 and 14 years, but it happens every time. Right now, we’re in a solar minima, so all is nice and quiet. Around 2011 however, things are going to be a bit stormier out in space. The solar maxima causes vast coronal mass ejections, solar flares powerful enough to knock satellites offline and generally, the most spectacular Aurora Borealis you’ll ever see.
In the past, times of solar maxima have caused flares large enough to interfere with ground-based communications, and on extremely rare occasions, Aurorae far enough Southwards to be visible over Plymouth! Mercifully, the worst thing most of us will notice is a case of solar acne. Sunspots are the most well known effect of the solar cycle. What exactly causes this cycle isn’t that well understood, even though people have been studying the sun for hundreds of years. Current theories say it’s all to do with streams of plasma circulating between the sun’s equator and poles… In a way, it’s like solar weather.
Of course, a lot of things that are true about the Sun are true of other stars, being as the Sun’s a star and all. Starspots have been observed elsewhere in the sky, as have flares. It varies to do with the star itself – seemingly, lower mass stars are more convective, and have larger flares (probably because there’s less gravity acting on the material being ejected).
The matter of flares, I find particularly interesting, especially given it may have an effect on any circumstellar chemistry going on. If flares do have such an effect, then you have to wonder what repurcussions a stellar cycle might have too. Of course, this is speculation on my part, but it’s an interesting thought. Either way, some of the chemistries I’ll be researching may be prominently affected by stellar phenomena. X-rays and high energy particles can break chemical bonds, knock away electrons, create free radicals… some energetic particles can even shatter atomic nuclei and create new elements. Interesting how the Sun provided such inspiration for the alchemists of old…