Although the idea of an asteroid colliding with Earth is common trope in science fiction, the threat of such an event is very real. Thousands of asteroids and comets in our solar system have been identified as possible threats known as near-Earth objects, or NEOs. Though many are relatively small, even small asteroids can cause disproportionate devastation. Due to the threat NEOs pose, they are being monitored by government agencies. Several methods of protecting the planet from collision have been proposed, though currently none are being actively pursued.
Near-Earth objects are defined as comets (icy bodies) and asteroids (rocky bodies) that come close the Earth during their orbit around the Sun. These objects can range in size from a few meters to several kilometers. So far, 11,573 NEOs have been discovered. Although most are small, over 800 are larger than one kilometer in diameter. Objects are further classified …show more content…
However, even small objects are capable of creating incredible destruction. In 1908, an asteroid only about 35 meters (120 feet) across detonated over Siberia in what became known as the Tunguska Event. The explosion was a result of the intense heat and pressure on the object, and released as much energy as 185 Hiroshima-grade atomic bombs. Eight hundred square miles of forest were destroyed. Though no humans were reported killed, there certainly would have been casualties had the asteroid burst over a populated area. The damage that such an object could cause, both environmental and economic, make it a relevant concern to governments around the world.
Understanding the threat NEOs pose to society, the United States Congress gave two mandates to NASA. First, the agency was directed to identify 90% of NEOs one kilometer in diameter or larger by 2008. Second, NASA was to identify 90% of NEOs 140 meters in diameter or larger by 2020. Methods used to locate