Key Takeaways:
- Asteroid Apophis, measuring approximately 335 to 375 meters in diameter, was discovered on June 19, 2004, at the Kitt Peak National Observatory.
- Initially, Apophis received a level 4 on the Torino Impact Hazard Scale, indicating a calculated 2.7% chance of Earth impact in 2029.
- Further observations, including radar data from Goldstone and Green Bank Observatories in 2021, significantly improved the accuracy of Apophis's projected trajectory.
- Subsequent analysis eliminated the previously assessed risk of Earth impact by Apophis.
On June 19, 2004, at the Kitt Peak National Observatory in Tucson, Arizona, astronomers Roy Tucker, David Tholen, and Fabrizio Bernardi discovered Asteroid Apophis. This Near-Earth Object (NEO), approximately 1,099 to 1,230 feet (335 to 375 meters) wide, reached the highest ever rating of level 4 out of 10 on the Torino Impact Hazard Scale, which evaluates an asteroid’s threat to Earth. It was estimated to have a 2.7% chance of impacting Earth in 2029. However, subsequent observations and radar data, particularly in March of 2021 by NASA’s Goldstone Deep Space Communications Complex in California and the Green Bank Observatory, West Virginia, greatly refined its trajectory and ruled out any impact risk. The discovery and evolving risk assessment highlighted how continuous observation and precise calculations by planetary-defense programs at NASA, ESA, and other agencies could enable accurate risk assessment and advance deflection strategies.
