The asteroid YR4, recently discovered by astronomers, now has a 3.1% chance of hitting Earth in 2032, the highest level ever recorded since monitoring began, according to NASA calculations on Tuesday, February 18.

Estimated to be between 40 and 90 meters wide, this asteroid could hit Earth on December 22, 2032, according to estimates from international space agencies and potentially cause considerable damage, such as destroying a city.

A forecast to be taken with a pinch of salt, however, because it is based on preliminary data and is likely to change in the coming weeks and months, insist experts interviewed by AFP.

"I'm not panicking," Bruce Betts of the American organization Planetary Society assured AFP, while calling for close monitoring of the asteroid, named 2024 YR4.

If it were to crash to Earth, its impact could be 500 times more powerful than the Hiroshima nuclear bomb, according to current estimates. Enough to wipe out an entire city, for example, says Bruce Betts. Or even cause a tsunami, if the impact were close to an island or the coast.

No danger for the general public at the moment

Although the risk of collision is now considered low, it is the highest ever recorded in more than two decades of monitoring celestial objects.

Such an event is "very, very rare," Richard Moissl, head of the planetary defense office of the European Space Agency (ESA), told AFP, but he wanted to be reassuring: "for the general public, there is no danger at the moment," he said.

In the early 2000s, the asteroid Apophis had agitated the international scientific community with its 2.7% chance of hitting the Earth in 2029. A probability of impact which had quickly fallen close to zero.

Similarly, the forecast for 2024 YR4 is expected to evolve shortly as more data is collected to refine its trajectory and profile.

Scientists are counting on the James Webb Space Telescope to conduct more precise observations in March. But time is running out, as the asteroid is in an orbit that is moving away from Earth.

It should therefore disappear from the view of terrestrial telescopes in the coming months before becoming observable again in 2028, experts estimate.

Possible international space mission to deflect asteroid

According to their current observations, 2024 YR4 would be in the same category as an asteroid that crashed in 1908 in a remote region of Siberia, due to its brightness.

This poorly documented event, known as the Tunguska event, is said to have led to the destruction of hundreds of thousands of hectares of forest.

If the risk of such a catastrophe occurring in about eight years were to be confirmed, the international space community could consider a mission to divert the trajectory of the asteroid.

Scientists have been working on developing such planetary defenses for years. In 2022, a NASA mission managed to change the trajectory of a harmless asteroid by sending a spaceship crashing into it, a first worthy of a Hollywood script.