Taking Extreme Space Weather to the Extreme

Extreme Space Weather events are large solar flares or geomagnetic storms, which can cost billions of dollars to recover from. Geomagnetic storms are the source of the largest economic impacts as they can destroy the electrical grid for substantial periods of time. We have few examples of such events; the Carrington Event (the solar superstorm) is one that had superlatives in three categories: size of solar flare, drop in Dst, and amplitude of aa, but it happened before the growth of satellites and continent-spanning electrical grids. Kepler observations show that stars similar to the Sun can have flares releasing millions of times more energy than an X-class flare, an energy deposition that could strongly affect the atmosphere surrounding a planet orbiting such a star. What level of solar activity would be necessary to strongly affect the atmosphere of the Earth? Can we anticipate the effects of the coronal mass ejections and geomagnetic storms that might accompany these enormous flares? At the other extreme, what would space weather look like if the Sun stopped producing a magnetic field? These are the extremes of Space Weather explored in this talk.