1674508707 Three specks of dust reveal the secrets of an asteroid

Three specks of dust reveal the secrets of an asteroid

The three particles from the asteroid Itokawa showed that this type of space object is much older than previously thought and much harder.

That would involve revising plans to avoid a collision with Earth, according to a study published Monday in the journal Proceedings of the US National Academy of Sciences.

The capsule contains black dust resembling black sand.

This pod contains black dust that resembles black sand from Itokawa.

Photo: JAXA

The three samples were recovered from the asteroid in 2005 as it transited Earth about 300 million kilometers away. It took the Japanese Hayabusa spacecraft five years to return them from Itokawa to the blue planet, along with hundreds of other particles.

Fred Jourdan, a professor in the College of Earth and Planetary Sciences at Australia’s Curtin University, was trying to figure out the age of Itokawa, a type of asteroid said to have a loose cluster.

It results from piecing together the fragments of a monolith asteroid that has been pulverized by a shock.

Monolithic asteroids are said to have lifetimes of a few hundred million years and are gradually eroded by collisions with other asteroids.

Artist's rendering of the Hayabusa 2 probe collecting a sample of material from the asteroid Ruygu.

Artist’s rendering of the Hayabusa 2 probe collecting a sample of material from the asteroid Ruygu (with the robot Mascot).

Photo: JAXA

The loosely clustered asteroid, like Itokawa, has a very different structure. Featuring a motley collection of rocks, dust, gravel and even vacuum held together by a simple effect of gravity.

It’s like a giant space pillow, and pillows are good at absorbing shock, notes Professor Jourdan.

A very old asteroid

To find out how much, the team analyzed the crystal structure of the samples, looking for deformations from the impact Itokawa generated. And dated her too.

The conclusion is that Itokawa formed after a collision at least 4.2 billion years ago, almost as old as Earth (4.5 billion years) but importantly ten times older than the ages of similar-sized monolithic asteroids.

An age so venerable that Fred Jourdan is convinced some of his peers will not believe him.

The resilience of this type of space object to collision is so great that, according to the study, there should be many more of them than previously thought.

With the consequence of adapting the methods of protecting against a collision of the Earth by this type of asteroid, the geochemist notes.

According to the scientist, the DART experiment to deflect an asteroid, which was successfully carried out by NASA last year, shows that this is possible with an object like Itokawa.

To do this, however, a much greater force would have to be applied, for example with a nuclear warhead, so that the shock wave can deflect the asteroid from its orbit.