The potentially hazardous asteroid 2024 YR4 caused consternation over the last few weeks as its odds of hitting Earth in 2032 dramatically rose. Now, those odds have plummeted to near-zero, as astronomers’ calculations of the asteroid’s path have been updated to indicate that Earth is almost certainly not in the space rock’s plans.
Almost. According to NASA’s Center for Near-Earth Object Studies (CNEOS), the asteroid’s current chance of hitting the planet in 2032 is 0.28%, or a 1-in-360 shot. That is a far cry from just earlier this week, when models had the asteroid’s impact probability at a staggering 3.1%, or 1-in-32 odds. It’s safe to say we’re out of the woods—but perhaps still in the backyard of uncertainty? A beleaguered analogy, but suffice it to say that the odds are not zero—but the sudden plummet from such a (relatively) high probability is a sigh of relief.
Though 2024 YR4 isn’t a gigantic asteroid—its size estimates range from 130 to 300 feet wide (40 to 90 meters)—it still is large enough to destroy a large city or region if hit Earth. It just wouldn’t cause a global cataclysm. Hardly reassuring stuff. The asteroid’s impact probability made it a 3 on the Torino Impact Hazard Scale, which measures the danger posed by asteroids. Torino 3s have “a 1% or greater chance of collision capable of localized destruction,” according to CNEOS.
Since the asteroid’s impact odds are now 1-in-360, the asteroid’s Torino risk is rated 1, meaning a “routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger. Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern.”
When 2024 YR4’s odds rose earlier this week, it became more hazardous than the head-turning asteroid Apophis, which was one of the most hazardous asteroids when discovered in 2004, but was found in 2021 to not be at risk of hitting Earth for at least a century.
The Asteroid Terrestrial-impact Last Alert System (ATLAS) first spotted 2024 YR4 just after Christmas, when the rock was 515,116 miles (829,000 kilometers) from Earth. Within a month, the asteroid’s odds crept up to a 1.2% chance—which sounds small, but is still a serious number when we’re talking about the chances of an asteroid with the potential to raze an entire city or region on our verdant little world. The odds kept growing, from a 1.58% chance of impact on February 2 to a 2.2% chance of striking on February 10.
But as experts told Gizmodo, this steady movement in the odds was expected. That’s because, as astronomers narrowed the range of potential paths for the asteroid, Earth remained in it. So while the total pool of paths shrank, Earth’s placement in the path meant its footprint covered more of the total possible area. Now, the asteroid’s potential path window has shrunk enough that it seems very unlikely that the rock will hit Earth.
The asteroid is moving away from Earth, but will swing by the planet in 2028 with a first potential impact in 2032. By April, astronomers expect the asteroid to be too faint for even the largest ground-based telescopes to see, so it was critical for researchers to make as many observations of the object as possible before then—time was of the essence to make educated guesses about its impact probability.
2024 YR4 still poses the slightest risk to Earth within the next 100 years, but recent estimates from space agency experts suggest there’s much less to worry about now.
