The solar cycle swings between solar maximum and solar minimum and for the past few years we have been in the peak of that cycle. Over the last 12 months or so however, the sun has well and truly moved into its less active period – known as solar minimum.
What is the Solar Cycle?
The solar cycle has been documented for centuries and is basically a (roughly) 11 year cycle of solar activity. Peak periods are characterised by a dramatic increase in sunspots, which are dark (and slightly cooler) patches on the suns disc. Each peak lasts a few years and this time round there has been significant solar activity (ie regular sunspots and solar flares) from around 2012 to 2015. 2017 started with a long stretch of zero sunspots and it would appear we are well on the way to solar minimum.
Solar Minimum and the Aurora
The period of solar minimum will result in a lot less regular aurora here on earth, due to the relative stability of the solar surface. It does not mean there will be no aurora at all, as the solar wind can still escape the sun through “coronal holes” as was the case last week. These photos are from Wednesday night (Jan 18) at Cradle Mountain. It was a relatively weak aurora but the pinky-purple hue was really quite nice. As was the position of the Milky Way and Magellanic Clouds.
For more of my aurora photos, check out my aurora index page of a list (and links) to all my aurora chasing from the past few years.