(NEW YORK) — Astronomers have gotten a glimpse of the “city-killer” asteroid before it disappears until 2028, according to NASA.
The space rock, called 2024 YR4, was previously given up to a 3.1% chance of striking Earth in December 2032, but astronomers have since eliminated the possibility of a strike at that time based on further observations.
Astronomers are watching 2024 YR4 closely, trying to learn everything they can before it disappears from view by mid-April, Kelly Fast, a planetary defense officer at NASA, told ABC News earlier this year. Its unique elongated orbit takes the asteroid around the sun and into Earth’s vicinity before it ventures far out between the orbits of Mars and Jupiter and out of sight, Fast said.
NASA’s Center for Near Earth Object Studies used the James Webb Space Telescope — the largest, most powerful telescope ever launched into space — to capture photos of the asteroid, the space agency announced on Wednesday.
New infrared observations indicate that the asteroid measures between 174 feet and 220 feet in diameter — about the size of the 10-story building, according to NASA. While it is not forecast to strike Earth in 2032, the asteroid now has a 1.7% probability of hitting the moon at that time, the space agency said.
The space rock was first discovered on Dec. 27 by astronomers monitoring the ATLAS telescope at the University of Hawaii, Fast said.
In the past, even when the asteroid passed through the inner solar system, it didn’t always come close to where Earth was at the time, which is why it was only recently discovered, Fast said.
The asteroid has been dubbed a “city-killer” due to its size and potential to cause major destruction. It is large enough to cause localized damage were it to strike a populated city, Fast said.
In 1908, the similarly sized Tunguska asteroid flattened trees over an area of about 1,250 miles after it exploded in the skies over Siberia.
NASA has been tasked by Congress with locating asteroids larger than 450 feet in length, which are large enough to do “regional” damage in the event of a strike, Fast said.
The asteroid currently has a 1.1% chance of striking Earth on Dec. 22, 2047, according to NASA.
More than a 2% chance of an asteroid strike is “uncommon,” Davide Farnocchia, a navigation engineer with NASA’s Jet Propulsion Laboratory, told ABC News in February.
But astronomers will continue to monitor the asteroid closely.
“We don’t want to take any chances,” Farnocchia said.
Copyright © 2025, ABC Audio. All rights reserved.
