Illustration showing a view of Earth from the moon.
(Getty Images/NASA)
Earth has dodged a celestial bullet, but the moon might not be so lucky, and that has scientists keeping their telescopes and minds trained on a massive asteroid called “2024 YR4.” That’s not its official name, but more on that later.
When it was first discovered, this asteroid had a very small chance of impacting Earth in December of 2032, but later observations concluded the space rock no longer poses any significant risk to our planet.
Since then, additional data has helped experts refine the asteroid’s potential trajectory and they say the probability of it striking the moon in 2032 has now risen to 4.3%. That’s still a very small chance, but there could be some complications for our planet if that collision happens.
Weather in your inbox
(MORE: Lego Man’s Epic Space Journey)
Back To The Beginning
2024 YR4 first caught astronomers’ attention in December 2024. It made headlines when its probability of impacting Earth got as high as 3%.
It’s so far away that it appears as just a tiny glimmer, but using infrared images captured by NASA’s James Webb Space Telescope, scientists estimate that it’s the size of a 10-story building, about 200 feet in diameter.
It’s considered a near-Earth asteroid, meaning it’s in an orbit that brings it within Earth’s region of the solar system.
Its size earned the asteroid the nickname “city killer” since it could cause severe damage to a city or region if it struck Earth.
2024 YR4 is the temporary name given to the rock. While those who discovered it will get to suggest an official name, it could be months or years before that official name is decided by the International Astronomical Union.
What Happens If It Strikes The Moon?
Illustration of an asteroid about to strike the moon, with a view of Earth.
(Madie Homan)
If this asteroid hits the moon, scientists say it will make impact at a speed of tens of thousands of miles per hour. That would create a huge crater, but more importantly, it could also send fragments of moon rock and granular lunar material flying off the moon.
While it’s unlikely the Earth would face any significant danger from the lunar strike, that debris could put nearby astronauts at risk, as well as satellites that we depend on for GPS, cellphones, internet and weather forecasting.
What about the International Space Station? Well that would be at risk, except that NASA plans to decommission and deorbit the ISS in 2031, a year before the asteroid’s potential impact.
(MORE: New Images Show Universe Like Never Before)
Would We Be Able To See The Collision?
The latest calculations from June suggest it’s likely the asteroid could hit the near side of the moon, the side pointing towards us.
So we could be able to see the once-in-a-lifetime collision here on Earth. Dr. Paul Wiegert, a physics and astronomy professor at Western University told Western News, “If YR4 hits the moon, it will be the largest asteroid to have hit the moon in about 5,000 years. It’s quite a rare event.”
Wiegert says, “People at home will be able to see the explosion with small telescopes or even binoculars.”
He also says that if moon rock is launched into space, “We should also get to see quite a spectacular meteor shower,” within a week of the collision.
So What Now?
Asteroid 2024 YR4 is currently too far away to detect with space or ground-based telescopes, as it orbits around the sun. But out of sight, does not mean out of mind – NASA expects to make more observations and collect new data when the asteroid’s orbit brings it back into Earth’s vicinity in 2028.