Largest Sunspot in 10 Years
April 04, 2001
The fast-growing sunspot 9393 (in the wihite circle) covered an area of the solar disk equivalent to the surface area of 13 planet Earths on March 29. That makes it the largest sunspot of the current solar cycle. Sunspots are relatively cool areas that appear as dark blemishes on the face of the sun. They are formed when magnetic field lines just below the sun's surface are twisted and poke though the solar photosphere. The twisted magnetic field above sunspots are sites where solar flares are observed to occur. Every 11 years the sun undergoes a period of activity called the "solar maximum", followed by a period of quiet called the "solar minimum". During the solar maximum there are many sunspots, solar flares, and coronal mass ejections, all of which can affect communications and weather here on Earth.