To most people, the sun is a steady, never-changing source of heat and light. But to scientists, it's a dynamic star, constantly in flux, sending energy out into space. Experts say the sun is now in its most active period in two decades, causing potential disruptions to radio and satellite communications. John Yang speaks with Bill Murtagh of NOAA's Space Weather Prediction Center to learn more. PBS News is supported by - https://www.pbs.org/newshour/about/funders