Artist rendering of an asteroid nearing Earth. Credit: Kevin M. Gill
UH-operated telescopes on Maunakea and Haleakalā are actively tracking an asteroid that could potentially strike Earth in 2032. Dubbed 2024 YR4, the asteroid was discovered by a UH telescope in December last year and is estimated to be roughly the size of a 20-story building. Scientists say it has a 1% chance of colliding with Earth—the highest impact probability of a large asteroid since near-Earth object tracking began two decades ago.
In the unlikely event 2024 YR4’s trajectory aligns with Earth, NASA has an ingenious defense plan. In 2021, the agency successfully altered the orbit of an asteroid during the Double Asteroid Redirection Test (DART)—an asteroid targeting system that crashed a small spacecraft into an asteroid and knocked it off course. UH telescopes played an instrumental role in DART, observing the spacecraft’s collision and monitoring its effects.
The telescope that discovered 2024 YR4 last year is part of UHʻs Asteroid Terrestrial-impact Last Alert System (ATLAS)—a network of telescopes operated in Hawaiʻi, Chile, and South Africa.
“Hawaiʻi’s telescopes are some of the most important tools for planetary defense,” said Doug Simons, director at University of Hawaiʻi’s Institute for Astronomy. “Thanks to our prime location and advanced technology, we can spot, track, and study asteroids with incredible accuracy. That gives scientists the time they need to evaluate potential threats and figure out the best ways to respond.”