A newly discovered, far-flung asteroid has sparked curiosity and a healthy side of concern among scientists who say the huge rock has the potential to make impact with Earth.
Based on projections, the asteroid, dubbed 2024 YR4, has a little more than one per cent chance of impact with Earth on Dec. 22, 2032.
But that doesn’t mean you should panic — at least not yet, anyway.
NASA’s Asteroid Terrestrial-impact Last Alert System (ATLAS) in Chile first detected 2024 YR4 in late December while hunting for near-Earth objects.
ATLAS reported the sighting on Dec. 27, 2024 to the Minor Planet Centre, the official group for observing and reporting new asteroids, small bodies and comets in the solar system.
“It is rare to have an asteroid with a non-zero probability of hitting Earth,” Heidi Hammel, vice-president of the Planetary Society’s board of directors, said in a press release about the asteroid. “At this point, astronomers have measured the object’s orbit, and further observations will refine that orbit to give us a more precise understanding of its potential danger.”
What’s known about the asteroid
The asteroid measures between 40 and 90 metres wide (130 and 300 feet) based on estimates from its reflected light.
“An asteroid this size impacts Earth on average every few thousand years and could cause severe damage to a local region,” the European Space Agency (ESA) said in a space safety briefing.
“As a result, the object rose to the top of ESA’s asteroid risk list.”
Based on simulated possible future orbits, astronomers now say there is a 1.3 per cent chance that the asteroid will strike Earth, but at this point, it’s hard to say where the unlikely collision would happen.
A statement published last week by the International Asteroid Warning Network says the impact risk corridor extends “across the eastern Pacific Ocean, northern South America, the Atlantic Ocean, Africa, the Arabian Sea, and South Asia,” and that there could be “severe blast damage” spanning as far as 50 kilometres from the impact site.
Get breaking National news
For now, YR4 has been given a Level 3 rating out of 10 on the Torino Impact Hazard Scale, meaning a close encounter with the asteroid is “meriting attention by astronomers,” according to NASA’s Center for Near-Earth Object Studies (CNEOS). A collision with Earth is only certain when an object reaches an 8, 9 or 10 rating, with higher ratings indicating more damage likely to be caused.
CNEOS says that while there’s a possibility the asteroid could make potential impacts on Earth six times between 2032 and 2071, the probability drops with each subsequent pass.
“It is moving away from the Sun, getting farther and farther and fainter and fainter,” Paul Chodas, the director of CNEOS, told Gizmodo. “The key thing is that it’s fading. It requires larger and larger telescopes to detect, and by April we think it’ll be too faint to observe with the largest telescopes.”
The asteroid follows an elliptical, four-year orbit, swinging through the inner planets before passing Mars and heading out toward Jupiter.
For now, it’s heading away from Earth and its next close pass won’t come until 2028.
Orbit of 2024 YR4 with positions as of January 31, 2025.
Handout / NASA /CNEOS
What happens if the risk grows
In the unlikely event that YR4 were to be on a collision course with our planet, one option would be to change the trajectory of the asteroid by slamming a robotic spacecraft into it, similar to the successful DART test mission by NASA in 2022, which changed the course of an asteroid that was of no threat to Earth.
Asteroids that are initially calculated to have a small chance of slamming into Earth are usually downgraded to have a lower probability of doing so over an extended observation period.
As the BBC notes, this happened in 2004 when an asteroid called Apophis was calculated to have a 2.7 per cent chance of hitting Earth in 2029, which was later ruled out after further observation.
The good news, according to NASA, is that for now, no other known large asteroids have an impact probability above one per cent.
