After months of quiet simmering, the Sun at last let loose at the end of October, spewing flare after flare in a resurgence that can only mean one thing: the second half of the double-peaked solar maximum has arrived.
2013 was long anticipated as the year of a solar maximum, that once-every-eleven-years period of time when the Sun becomes extremely energetic, letting off coronal mass ejections and solar flares from darkened sunspots, shooting out violent solar winds to disrupt electromagnetic transmissions of all varieties and leave its mark in haunting swirls of green above Earth’s poles.
But that’s not what happened, exactly. After a couple spurts early in the year, the Sun seemed to just peter out.
At first, heliophysicists were puzzled. All the signs had pointed to a solar max taking place in 2013. Then came the new hypothesis: a double peaked solar maximum. According to that theory, instead of a single fiery climax, the Sun would exhibit a small peak, taper off into a valley, then peak again at the end of 2013 into the beginning of 2014.
Well, the end of 2013 is upon us, and so is a very active Sun. October 27th, 28th, and 29th all saw X-class flares, the strongest and most dangerous variety. NASA reported three X-class flares between October 23rd and 28th, accompanied by more than 15 M-class flares, one level down.
So far, the flares haven’t proven particularly hazardous, having shot off radiating winds in directions other than Earth. But with our view of the Sun currently pockmarked with 132 visible sunspots, ripe breeding grounds for flares and coronal mass ejections, we can be pretty sure that more is yet to come.
That ‘more’ can be a problem here on Earth. The sometimes severe geomagnetic storms that bombard Earth’s magnetosphere are no joking matter. While the magnetosphere absorbs much of the energy from these impacts, it cannot protect the satellites outside its limits nor the exposed polar regions below. Strong storms can break through these defenses entirely to affect the entire globe.
Those who keep an eye on space weather know that we are sitting on a ticking bomb when it comes to solar weather impacts. On a regular basis, airliners are required to reroute to avoid excessive radiation exposure in polar routes during severe events. (As a result of these periodic exposures, airline pilots are classified as radiation workers in the US, receiving about the same radiation exposure on an annual basis as nuclear power plant workers.) Satellite operators know to batten down the hatches when a coronal mass ejection comes through, making sure any sensitive systems are powered down to avoid aberrations. But that is nothing compared to what could happen if a really strong geomagnetic storm hits: at a minimum, we could be facing complete loss of access to our electrical grids. At worst, those power outages would be accompanied by electrical fires and shorts combined with loss of access to critical spacecraft infrastructure that would make getting back to business a prolonged and smoky process.
For this reason, space weather and space weather prediction remains a global concern at the policy level. But even “nowcasting,” i.e. understanding local and global radiation events occurring in the present, can be a challenge. Nowcasting is the focus of a new NASA model designed to help effectively plan flight paths, called Nowcast of Atmosphere Ionizing Radiation for Aviation Safety or NAIRAS. Check out the video below for an introduction from NAIRAS’ principal investigator.
In the meantime, keep an eye out for some great aurorae in higher latitudes as we see the impact of flares already emitted and look ahead to more to come. Welcome to Solar Maximum 2013 Part 2.
Image caption: The Sun on October 31, as seen from the Solar Dynamics Observatory (Credits: NASA).