According to NASA, an asteroid denoted as 99942 Apophis will make a rare pass incredibly close to the Earth during its next flyby in 2029. The asteroid, which was first discovered in 2004, was initially rated as a level 4 on the 10-point Torino scale, which measures the impact hazard of near-Earth objects.
On April 13th, 2029, Apophis will pass within 20,000 miles of the Earth. While this may sound like a very significant distance, it is quite short in astronomical terms. Apophis will, for example, pass much closer to the Earth than the Moon, which orbits at an average distance of approximately 238,855 miles. Apophis is also expected to pass lower than some man-made satellites. Artificial satellites in geosynchronous orbit are positioned at 22,236 miles above the Earth, just outside the predicted path of the asteroid. For those living in areas beneath the path of Apophis, it will even be visible to the naked eye.
Apophis measures approximately 1,100 feet in width, more than large enough to cause massive devastation in the event of a future collision. For reference, a recent simulation of the impact of a similarly sized asteroid in New York City found that anything within 9.3 miles of the impact would be unsurvivable, while damage would be done as far as 42 miles away.
Fortunately, scientists now believe that there is no reason to be concerned about the close pass of Apophis in 2029. It is, however, being treated by the scientific community as a rare opportunity to study an asteroid directly. One of the most important questions to be answered is how exposure to Earth’s gravity will affect the asteroid’s path through space. Scientists also hope to learn more about its composition and interior. It is even possible that a spacecraft probe could be launched to attach to Apophis during the pass near Earth to send back critical data about the asteroid.
Apophis will return to Earth in 2036, then make additional passes in the decades to follow. At present, the chances of a future impact are placed at less than 1 in 100,000. Data gleaned from Apophis, however, could be valuable in formulating future planetary defense plans, as the asteroid is one of roughly 2,000 that are believed to present a possible future impact hazard.