According to a report by Space.com, scientists say there’s currently a 4% chance the asteroid could hit the Moon. Although it no longer poses any threat to our planet, a possible collision with the Moon could have effects that go beyond just a big lunar crater.
No risk to Earth, but the Moon is being monitored
As per Space.com, asteroid 2024 YR4 was initially flagged with a 1 in 43 chance of hitting Earth. However, with fresh telescope data, astronomers have ruled out that possibility. Now, their focus has shifted to the Moon, which may be in the asteroid’s path when it makes a close approach in 2032.
Astronomer Paul Wiegert from the University of Western Ontario told Space.com, “A 2024 YR4 impact on the moon would pose no risk to anything on the surface of the Earth… but the impact could pose some danger to equipment or astronauts (if any) on the moon, and certainly to satellites and other Earth-orbiting platforms.”
How strong would a lunar impact be?
If asteroid 2024 YR4 does strike the Moon, scientists estimate it could release energy equal to 6 million tons of TNT, making it the largest lunar impact in nearly 5,000 years. The impact could create a 1-kilometre-wide crater, says the Space.com report.
Most of the debris from such a collision would fall back to the Moon. However, experts suggest that a small percentage, around 0.02% to 0.2%, could escape into space, which raises new concerns for objects in orbit around Earth.
Could lunar debris threaten satellites?
Although Earth is safe from any direct impact, space debris could still be a problem. Wiegert, as quoted by Space.com, explained that this debris could add “a flux of meteoroids 10 to 1,000 times higher than the normal background for a few days.”Travelling at speeds of nearly 22,400 miles per hour (or 10 km/s), these fragments might be slower than typical meteors but still fast enough to damage satellites or space-based assets. Some of this material could orbit Earth for years, posing a long-term risk to space infrastructure.
Is Earth completely safe from the debris?
Yes, says Wiegert, the surface of Earth is protected by its atmosphere. “The debris will burn up… we don’t expect there to be many pieces large enough to survive,” he told Space.com. To cause any damage on Earth, a piece would need to be 1 metre or larger, and most expected debris will be much smaller, more like pebbles or dust.
Still, for satellite operators and space agencies, even small particles in orbit can cause trouble, making this potential Moon strike worth tracking closely.
Does this need a new asteroid threat scale?
The idea of creating a new risk scale for events like this has been raised, but experts aren’t convinced. Planetary scientist Richard P. Binzel of MIT told Space.com that a new scale isn’t needed, as “the indirect consequences are too varied to compress into a single scale.”
He added that asteroid monitoring is already effective, saying, “What one can control… is determining with certainty whether you have a hit or miss.”
What happens next? Wait till 2028 for updates
For now, astronomers will wait until 2028, when asteroid 2024 YR4 comes into view again. That’s when they expect to update the Moon impact probability, which currently sits at 4%.
“The whole event would be exciting to watch in binoculars or a small telescope,” Wiegert told Space.com. The current research findings have been submitted to the American Astronomical Society and are also available as a preprint on arXiv, according to the same report.
Inputs from TOI