The Earth constantly receives radiation from astrophysical objects and events. The Sun, of course, produces a constant stream of photons and charged particles that both benefit and harm life on our planet. More energetic but short lived solar events can have larger effects. In addition, astrophysical events far beyond the borders of our solar system can have major effects on the Earth. These events are much less frequent, but much more energetic, and may have connections to one or more of the extinction episodes in the history of life. I will review what we know about the various astrophysical events that could be significant, how often they may occur and what the effects are or would be on the Earth's atmosphere and biosphere.
Refreshments in CW 119 at 4:15 p.m.