As scientists have continued to study the sun and its many influences upon the earth, they have discovered many subtle interconnections. Apart from its obvious warmth and light, the sun produces many other dramatic impacts upon humans and their activity on the ground and in space.
Solar storms have interferred with the smooth operation of satellites in space. Sometimes satellites have been damaged because of electrical problems or false commands triggered by high energy charged particles.
The most dramatic affects involve power black outs caused by solar storms such as the one that occurred on March 10, 1989. A surge of electricity caused part of the power grid in eastern Quebec to shut down for hours affecting 6 million people for 9 hours.
During the early 1600's observers saw very few sunspots, and no cyclic changes in their numbers. This was also a time when Europe was affected by the so-called 'Little Ice Age'. Similar climate and solar activity correlations have also been found by studying ancient Chinese sunspot records going back thousands of years. Whenever solar activity seems to be dramatically low, or absent for a few decades, some part of the Earth seems to experience a major cooling episode.
Solar activity also affects the amount of light and heat we receive at the earth. Since the 1970's sensitive satellites have measured the power output of the sun. You would expect that when dark sunspots are present that the sun should be a little less bright. In fact the opposite is seen! This happens because sunspots are accompanied by brightenings of the surrounding solar surface far away from the darkened sunspot region, and this brightening more than compensates for the loss of light due to the sunspot itself.