I can’t recall seeing the sun this peppered with sunspots in a long time. Through the scope this morning I counted nine separate groups. No single spot or group stood out as unusually large, but the combined effect of seeing so many blemishes in one glance made an impression. I encourage you to point your telescope – suitably equipped with a safe solar filter of course – at the sun today to appreciate how fraught with magnetic activity our sun has become.
Each group marks a region on the sun’s shiny outer skin called the photosphere where magnetic energy is concentrated. Strong magnetic fields within a sunspot group quell the turbulent churning of the photosphere, chilling the region by several thousand degrees. Sunspots appear dark against the sun’s blazing disk because they’re cooler.
Energy stored in sunspots’ twisted magnetic fields can suddenly be released in violent, explosions called solar flares. Billions of tons of solar plasma – the sizzling mix of protons and electrons that composes the sun – are heated to millions of degrees during the explosion and rapidly accelerated into space. Radiation from radio waves to X-rays and gamma rays fan out at the speed of light. Fortunate for us, our atmosphere and planetary magnetic field protect us from most of what flares can dish out.
Not everything though. Strong X-class flares can cause radio blackouts, damage satellite electronics and disrupt poorly protected power grids. They also can spark displays of northern lights. An M-class flare from sunspot region 2035 on April 16 may kick off auroras overnight Saturday April 19-20. NOAA forecasters predict a 25% chance of a minor auroral storm.
Video of February’s X4.9 flare shown in multiple wavelengths of light
Conditions are ideal if it comes to pass. Moonlight won’t be a problem and night temperatures are decidedly more pleasant than in February.