Asteroids exploded “ similar to a bomb ” on France in a rare event

An asteroid exploded on France two years ago in a single unique explosive event, raising concerns concerning the future planetary defense of certain types of these rocky bodies.

On February 13, 2023, a small asteroid called 2023 CX1 entered the atmosphere of the earth and crossed the sky of Normandy. The event was one of the rare meteors that were followed before entering our atmosphere, it being seen about seven hours earlier.

The event has produced a shiny fire ball and several meteorites that have been collected on the ground. Only two asteroids were followed and have recovered fragments of a fall on the ground; The second was in Germany in 2024.

The examination of the images of the cameras which followed the descent of the asteroid, Auriane Egal at the University of Western Ontario in Canada and her colleagues have spotted something unusual. Most asteroids gradually separate when they enter the earth’s atmosphere, but 2023 CX1 seems to have survived almost entirely intact until it reaches an altitude of 28 kilometers, where it exploded in a single catastrophic event with an energy of approximately 0.029 kilotons, equivalent to about 29 tonnes of TNT and lost approximately 98 percent of its mask.

“It was similar to a bomb,” said Egal, adding that it was a “single blow that generated a spherical shock wave, not multiple detonations throughout its trajectory”.

The 2023 CX1 asteroid was small, only about 72 centimeters in diameter – the size of a beach ball – so it did not cause any problem on the ground. But if a larger asteroid exploded in a similar way, it could cause more damage than that which has disintegrated more gradually in the atmosphere.

A single asteroid has been exploded in this way before: the Novo Mesto Meteor on Slovenia in 2020, which lost around 80% of its mass in a single explosion.

“This type of fragmentation is more dangerous,” explains Egal. “If you have a larger asteroid, its effects will be amplified. Perhaps we have to evacuate a larger area near the planned impact site, “if the asteroid was large enough for such an action to be necessary.

Why this asteroid survived much lower in the atmosphere is not entirely clear, but it could be linked to its origin. The asteroid was a fairly common type known under the name of chondrite L, comprising about a third of all the meteorites of the earth, and perhaps coming from a parent asteroid in the interior asteroid belt called Massalia which had experienced collisions before, hardening 2023 CX1 before the fall, according to Egal and its team, which studied a meteorite from the fall.

“We have several shock veins in the meteorite which are witnesses [to] Lots of impacts, “she said.” Perhaps this network of veins stuck the rock together, and that is why it is better than other typical meteorites. “”

This could mean that we must be wary of the asteroids of Chondrite L similar in the future, especially the older ones, explains Thomas Burbine at Mount Holyoke College in Massachusetts. “It is a very common type of meteorite, so it is the greatest concern,” he says. “These L chondrites could cause more damage than expected.”

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