For most of us, the Moon seems like the most stable presence in the night sky. After all, it’s been circling Earth for billions of years, illuminating poetry, calendars, and even regulating the tides. It almost seems untouchable… But NASA scientists are now issuing updates that sound like the beginning of a science fiction story: the Moon, they say, could be hit by a speeding visitor from deep space. These aren’t conspiracy theories or vague predictions. We’re talking about real data collected by the James Webb Space Telescope (JWST), and the numbers are serious enough to draw attention. For the first time in years, our cosmic neighbor appears as a potential target in official calculations.
Telescopes rewrote the odds
First, we need to remember that, in recent decades, telescopes like Hubble and, more recently, James Webb have completely changed the way we observe the universe. They allow us to clearly see what was previously invisible; from the birth of galaxies to discreet asteroids crossing our orbit. That’s why in May, Webb turned its sharp eyes to a barely visible, moving dot.
This observation altered the odds of a future collision. The “high-speed threat” in question is asteroid 2024 YR4, a space rock between 53 and 67 meters across, roughly the size of a ten-story building. When it was discovered in late 2024, it gained notoriety for another reason: for a brief period, it carried the highest chance ever recorded of hitting Earth among large asteroids. Turning to numbers, initial estimates indicated a 3.1% chance of a collision with Earth in 2032. This may seem small, but in terms of planetary defense, this was unprecedented, enough to send scientists into crisis simulation mode.
If the Moon takes the hit: danger dismissed, discovery unlocked
But what would it mean if 2024 YR4 hit the Moon? The short answer: a spectacular crater, but no risk to Earth. Astronomer Pawan Kumar, a former researcher at the Indian Institute of Astrophysics, explained: “It won’t be a cause for concern. Because any lunar debris blasted into space from the impact would blow up in Earth’s atmosphere if any of it makes it to near-Earth space.”
However, even if the lunar orbit remained intact, the event could still bring interesting effects, such as:
- A fresh crater, visible to telescopes and perhaps even to amateur astronomers.
- Small fragments streaking across the sky, burning up in the atmosphere, and producing possible meteor showers.
- A unique opportunity for science to test, in real time, what it knows about impacts.
It’s a disturbing thought, but also a scientific gift: a natural experiment taking place right next to Earth. So we need to pay close attention to upcoming observations, just as we did when the James Webb unexpectedly changed course.
From drill to dress rehearsal: how asteroid 2024 YR4 sharpened planetary defense
Even without an immediate threat to us, the 2024 YR4 saga was valuable. This is because it served as a “complete rehearsal” for planetary defense: discovery, risk assessment, public communication, and long-term monitoring. It’s worth remembering that this isn’t the first time NASA has trained for something like this. Back in 2022, the agency carried out the DART mission, deliberately colliding a spacecraft with an asteroid and altering its orbit. This feat proved that diversion strategies aren’t just theory; they work.
YR4 will become visible again in 2028, when Webb and ground-based telescopes will measure its composition and shape. These details are crucial: how an asteroid fragments or absorbs impact depends on its density and structure. Of course, even though it’s ruled out as a threat, it will be studied closely when it makes a close pass in the 2030s, just as NASA is doing with this other asteroid that is already close to Earth.
