n 2005 the United States Congress mandated that NASA find 90 percent of large Near Earth asteroids (NEAs)-those that have the potential to impact Earth-by the year 2020. This mandate was created in response to recent scientific data indicating large impact events were common in Earth's geologic past and therefore will likely occur again in the future. Many new NEAs have been discovered as a result of NASA's efforts and research is under way to find ways to stop such impact events from occurring. The above paragraph suggests that, unlike other natural hazards, asteroid impacts .