Sunspots (dark areas) on the surface of the Sun, with filaments and lighter patches known as 'plages'. This image covers about a third of the width of the solar disc. Sunspots are areas of magnetic activity that are cooler than the rest of the Sun's surface. They range in size from hundreds to thousands of kilometres across. The darkest regions (nearly vertical magnetic fields) are the umbras, surrounded by penumbras (bronze regions). The background consists of convection cells called solar granules. This image of the chromosphere was obtained in 2015 by an H-alpha telescope at the European Space Astronomy Center (ESAC) in Madrid, Spain.