National Aeronautics and Space Administration’s (NASA) astronomers have predicted that the Asteroid 99942 Apophis, a near-Earth object (NEO) will pass less than 20,000 miles (32,200 kms) of Earth in 2029.
Discovered in 2004, Apophis was identified as one of the most hazardous asteroids that could impact Earth. However, once astronomers tracked Apophis and deepened understanding of its orbit, the estimation of its impact changed.
Estimated to be about 1,100 feet (340 meters) across, Apophis quickly gained notoriety as an asteroid that could pose a serious threat to Earth when astronomers predicted that it would come uncomfortably close in 2029. Thanks to additional observations of Apophis, the risk of an impact in 2029 was later ruled out, as was the potential impact risk posed by another close approach in 2036. Until March 2021, however, a small chance of impact in 2068 still remained.
When Apophis made a distant flyby of Earth around March 5, 2021, astronomers took the opportunity to use powerful radar observations to update the calculation of its orbit around the Sun with extreme precision, enabling them to confidently rule out any impact risk in 2068 and long after. To arrive at the Apophis calculations in 2021, astronomers used the 70-meter (230-foot) radio antenna at the Deep Space Network’s Goldstone Deep Space Communications Complex near Barstow, California, to precisely track Apophis’ motion.
The radar team continues to analyze its data, and they expect to learn more about the asteroid’s shape. Previous radar observations have suggested that Apophis has a “bilobed,” or peanut-like, appearance. This is a relatively common shape among near-Earth asteroids larger than 660 feet (200 meters) in diameter, at least one in six have two lobes.
As predicted, on April 13, 2029, Apophis will pass close to our planet’s surface, closer than the distance of geosynchronous satellites. During that 2029 close approach, Apophis will be visible to observers on the ground in the Eastern Hemisphere without the aid of a telescope or binoculars. It’s also an unprecedented opportunity for astronomers to get a close-up view of a solar system relic that is now just a scientific curiosity and not an immediate hazard to our planet.
