A massive asteroid, named 2024 ON, is set to zip past Earth next Tuesday, missing our planet by a distance of about 2.6 times the average distance between Earth and the moon. The skyscraper-sized asteroid has an estimated diameter of between 721 and 1,575 feet (220-480 meters) and will fly by at approximately 19,842 mph (32,933 km/h), or around 26 times the speed of sound.
NASA deems any object that comes within 120 million miles (193 million kilometers) of Earth a “near-Earth object” and classifies large objects within 4.65 million miles (7.5 million kilometers) of our planet as “potentially hazardous.” The agency tracks the locations and orbits of roughly 28,000 asteroids using its Asteroid Terrestrial-impact Last Alert System (ATLAS), an array of four telescopes that scan the entire night sky every 24 hours.
Although 2024 ON would not cause a catastrophic event like the dinosaur-killing asteroid that struck Earth 66 million years ago, its effects wouldn’t be insignificant. For example, a similar-sized meteor exploded over Chelyabinsk, Russia in 2013, generating a blast roughly equal to around 400-500 kilotons of TNT and injuring around 1,500 people.
Understanding the trajectories of asteroids can be challenging due to the Yarkovsky effect, which means that space rocks absorb and emit enough momentum-carrying light to subtly change their orbits over time. This highlights the importance of quantifying this effect when predicting potential threats from asteroids.
Space agencies are already working on ways to deflect a dangerous asteroid if one ever heads our way. In September 2022, NASA’s Double Asteroid Redirection Test (DART) spacecraft successfully redirected the non-hazardous asteroid Dimorphos by ramming it off course, altering its orbit by 32 minutes. China is also planning an asteroid-redirect mission to divert the space rock Bennu, which will swing within 4.6 million miles of Earth’s orbit between 2175 and 2199.
For those interested in following the path of 2024 ON as it passes our planet, the Virtual Telescope Project will show a live feed of its course beginning on September 15 at 19:30 UTC, when the object will be visible in the Northern Hemisphere.
Source: https://www.livescience.com/space/asteroids/potentially-hazardous-asteroid-the-size-of-a-skyscraper-will-miss-earth-tuesday