Mon, 21 Aug 2017
After the eclipse...
Solar disc, 21 August 2017. Photo: SDO
If you saw the footage of the toal eclipse on TV, you may have noticed a scattering of sunspots across the disc. These show that although the Sun is winding down to solar activity minimum, it is by no means quiet. The central group is active region 2671, and the smaller group on the left (east) limb is AR 2672.
Although the presence of sunspots is no guarantee that the northern lights will grace our skies, they can't be ruled out, as the spot groups are sources of solar flares.
Notice that the spots seem to be strung out close to the Sun's equator. This is evidence that they are still part of the last solar cycle, which peaked in 2015 and is still declining in activity, and is expected to do so until at least 2020. Each solar cycle begins with spots much closer to the Sun's poles, and they move closer to the equator as the cycle continues. It will probably be some years before we again see sunspots at high solar latitudes, which will be the sign that the new solar cycle has started.
Added by: Robin Scagell