Collected image

PARIS, June 23, 2025 (BSS/AFP) - If a huge asteroid smashes into the Moon in 
2032, the gigantic explosion would send debris streaming towards Earth that 
would threaten satellites and create a spectacular meteor shower, according 
to researchers.

Earlier this year there were briefly fears that the 60-metre-wide (200-foot-
wide) asteroid called 2024 YR4, which is big enough to level a city, would 
strike Earth on December 22, 2032.

It was given the highest chance -- 3.1 percent -- of hitting our home planet 
that scientists have ever measured for such a giant space rock.

Subsequent observations from telescopes definitively ruled out a direct hit 
on Earth.

However, the odds that it will crash into the Moon have risen to 4.3 percent, 
according to data from the James Webb space telescope in May.

A new preprint study, which has not been peer-reviewed, is the first to 
estimate how such a collision could affect Earth.

It would be the largest asteroid to hit the Moon in around 5,000 years, lead 
study author Paul Wiegert of Canada's University of Western Ontario told AFP.

The impact would be "comparable to a large nuclear explosion in terms of the 
amount of energy released", he added.

Up to 100 million kilograms (220 million pounds) of material would shoot out 
from the Moon's surface, according to a series of simulations run by the 
researchers.

If the asteroid hit the side of the Moon facing Earth -- which is roughly a 
50-percent chance -- up to 10 percent of this debris could be pulled in by 
Earth's gravity over the following days, they said.

- 'Like a bullet' -

Earth's atmosphere would protect the surface from the millimetre- to 
centimetre-sized lunar rocks, Weigert said. 0.04-2.54

But these meteors could be capable of destroying some satellites -- and there 
are expected to be a lot more of those orbiting the planet by 2032. 

"A centimetre-sized rock travelling at tens of thousands of metres per second 
is a lot like a bullet," Wiegert said.

In the days after the impact, there could be more than 1,000 times the normal 
number of meteors threatening Earth's satellites, he added.

Meanwhile, those of us on the ground would be treated to a "spectacular" 
meteor shower lighting up the night sky, the study said.

But the current odds of a direct hit on the near side of the Moon remain at 
just two percent, Wiegert emphasised.

The asteroid is not expected to be visible again until 2028, so the world 
will have to wait to find out more.

If a direct hit is eventually found to be likely, humanity probably has 
enough time to plan a mission to spare the Moon.

"I'm sure it will be considered," Wiegert said.

The asteroid is half as wide and has 10 percent of the mass of Dimorphos, 
which NASA's DART mission smashed into in 2022, successfully changing its 
trajectory.

If 2024 YR4 is on a collision course with the Moon, it would be "a good 
target" for another test of our planetary defences, Wiegert said.

But if not, trying to deflect something zooming so close to Earth could be a 
little "dangerous", he added.

The preprint study, which published on the arXiv database last week, has been 
submitted to the Astrophysical Journal Letters.