Near-Earth asteroid 2013 NE19, which is about the size of a football field, passed within 2.6 million miles of Earth on July 22. There was no danger that it would strike Earth, but there is a concern because it was discovered just last Monday (July 15). Had it been aimed at Earth, we would have had just eight days to prepare. An object that size would have the potential to cause serious damage, even catastrophic damage, if it struck a populated area or a part of the ocean that might have led to tsunamis. There are estimated to be tens of thousands of undocumented asteroids in space, and so far no comprehensive program with sufficient funding to identify and track them all.