According to a NASA survey, there are around 1,000 asteroids close to Earth that are large enough to cause significant damage if they were to collide with our planet. This survey, known as Spaceguard, was initiated by Congress in 1998 with the goal of identifying 90 percent of objects near Earth that are at least 1 km in diameter. The survey has been completed, with 93 percent of the objects now identified. The data was presented by astronomer Amy Mainzer of NASA's Jet Propulsion Laboratory at a conference in San Francisco. In addition to the larger asteroids, NASA's Wide-field Infrared Survey Explorer (WISE) telescope also discovered approximately 20,500 smaller asteroids near Earth, which is fewer than previous estimates of 36,000 to 100,000 such objects. "We know something as large as that could potentially eliminate most life on Earth," Mainzer stated, emphasizing the destructive power of a major asteroid or comet impact. While the likelihood of such an event is low, scientists are actively monitoring potentially hazardous objects using archived WISE observations to identify any threats that come within about 4.6 million miles (7.4 million km) of Earth. As of now, there is no strategy in place for how to respond if an asteroid were to be found heading towards Earth.