THE SUN IS DIMMING: Today at the Cape Canaveral Air Force Station in Florida, SpaceX launched a new sensor to the International Space Station named "TSIS-1." Its mission: to measure the dimming of the sun. As the sunspot cycle plunges toward its 11-year minimum, NASA satellites are tracking a slight but significant decline in total solar irradiance (TSI). TSIS-1 will monitor this dimming with better precision than previous satellites as Solar Minimum approaches in the years ahead. Visit today's edition of Spaceweather.com to learn more about TSIS-1 and natural variations in the sun's electromagnetic output.
Above: This plot shows the total solar irradiance (TSI) since 1978 as observed by NASA and European satellites. The sun's electromagnetic output (top frame) waxes and wanes with the sunspot cycle (bottom frame).
