Photo by Ron Hipschman. Photo by Ron Hipschman. Meteorite samples courtesy of the California Academy of Sciences . From the abundance, characteristics, and location of these tektites, Fiske and his colleagues believe the impact of a mile-wide asteroid that formed them occurred relatively recently, about 770,000 years ago, the largest, most recent impact identified so far. Because meteorite impacts have occurred so infrequently in recent history, there aren't many clues for scientists to work with.
Impacts have the potential to cause massive damage to the earth and life on it.
But we really don't understand the details. Eleanor Helin discusses our options if faced with this extremely remote possibility. Sooner or later, history will repeat itself and a globe-threatening impactor will target our planet. There are programs in place to monitor the orbits of known asteroids and comets, and more near-earth objects are being discovered by amateur astronomers and the pros every year. In the best of circumstances, we could have decades, perhaps a century, of advance warning.