Explosions on the surface of the sun, known as solar flares, can have an impact on life and technology on Earth and experts say the sun is now in its most active period in two decades. Bill Murtagh is the program coordinator for the NOAA's Space Weather Prediction Center and described the sun as one big magnet with a north and south pole-- it also has negative and a positive polarity. Over the course of 11 years, the sun does a rotation of that polarity. "The sun is a big ball of electrically ch