Robert Weaver and Cathy Plesko, astrophysicts at Los Alamos National Laboratory, are part of a planetary defense team that's exploring ways to deflect an asteroid should it get within striking distance of Earth. The results of such an impact could be catastrophic. Weaver and Plesko use the Laboratory's supercomputers to create simulations of what would happen should the asteroid be deflected by a kinetic ("cannonball") or nuclear device.