We have just passed the Summer Solstice on 21st June where our Sun reached its highest point in the sky and gave us the longest day of the year. But back in May the Sun kicked out more than just sunlight. You may have seen in the news that around the world the night sky was lighting up in multi colours. On the evening of May 10th you may have even been out yourself in the dark countryside or on the cliffs with many others looking north to see the Aurora Borealis or Northern Lights. This was a spectacular show with patches, rays and ribbons of shifting greens, purples and reds covering the whole sky. If you took pictures with a mobile phone or a camera with the shutter open for 20-30 seconds the intense colour was well captured as in this image I got at my home in Rosenannon.
The Sun’s activity fluctuates on an 11-year solar cycle, with periods of peak activity known as solar maxima. Solar activity is now on the rise during the current solar cycle which is predicted to peak in 2025. The cause of all this spectacle was a complex massive sunspot (the size of 14 Earths!) on the face of the Sun which I imaged in the afternoon through a small telescope with a solar filter.
This sunspot spewed out charged particles that hit our Earth at 45 million mph and were captured along our planet’s magnetic field lines and funnelled into our north and south poles. The particle interaction with the atmospheric gases at varying heights causes the different colours to emanate like neon lights. Green auroras are produced when charged particles collide with high concentrations of oxygen molecules in Earth’s atmosphere at altitudes of around 60 to 190 miles. Red auroras occur when solar particles react with oxygen at higher altitudes, around 180 to 250 miles. Blue and purple auroras are even less common and also tend to appear during periods of high solar activity when solar particles collide with nitrogen in Earth’s atmosphere at an altitude of 60 miles or less. Some images taken by our club members are on this website HERE. So you don’t miss out on the next big show, for daily updates and forecasts of future solar activity and possible aurora, visit spaceweather.com
By Glynn Bennallick