Our Sun goes through a roughly 11 year cycle in which the number of sunspots and overall activity waxes and wanes. Astronomers have been observing this phenomenon for over a hundred years. We are entering cycle 25 based upon direct observations but cycles for the past 10,000 years have been reconstructed from tree rings and carbon dating. Solar flares in which the Sun releases streams of energetic particles are also correlated with sunspots and can affect weather on Earth and cause havoc with senstifive electronics in satellites and even disrupt the electrical grid (google the Carrington Event).
This photo was taken by my good friend Glenn Hitchcock who some of you may remebmer from the great 2017 Solar eclipse event. It was taken with a special filter and camera that can record the hydrogen-beta light from the Sun’s surface.