Space is radioactive. One of the main sources of the radioactivity is the Sun, whose magnetic plasma atmosphere—the corona—constantly streams into space as a “solar wind.” Occasionally the wind can ramp up to speeds of 2 million miles per hour and buffet the Earth’s magnetic field, causing geomagnetic storms that load up the Van Allen radiation belts, interfere with radio and GPS transmissions, and even drive electrical currents in the ground that can impact the power grid.
The most visible effect of this “space weather” is the aurora: radiation funneled into the polar regions lights up the night sky as the Earth’s magnetic field works to shield us from the solar wind. Do we need to worry? As ground-dwellers, the natural effects are rarely a concern—who doesn’t like a nice Northern Lights show? The concern is that in addition to solar wind, the Sun can occasionally flare up and spew massive coronal mass ejections, or CMEs, into space. When these “magnetic tsunamis” wash over the Earth, they trigger the largest space weather storms, flooding the ionosphere with X-rays, scrambling airline radio and GPS signals, swamping power grids, and spewing radiation that can penetrate the atmosphere. Astronauts traveling to the Moon or other planets outside the Earth’s protective magnetic shield are particularly at risk from these storms.
In this talk, Dr. Berger will describe the origins, impacts, and our current understanding of space weather and examine what we can do to provide the forecasts needed to protect our technological infrastructure and enable safer spaceflight.