Cathy Plesko is a Research Scientist in Applied Physics at Los Alamos National Laboratory. She uses the supercomputers there to study what happens when asteroids and comets hit a planet and how to prevent them from hitting Earth. She was a teenager when she became interested in asteroids and comets. Cathy was awarded her Ph. D. in Geophysics and Planetary Sciences in 2009. That was at UC Santa Cruz where she studied the effects that large asteroid and comet impacts had on the climate of Mars early in the history of the solar system. She has also studied asteroid impact mitigation, and uses those supercomputers to model how a nuclear explosion might deflect an asteroid just enough to miss our home planet.