A type of “hard-to-destroy” asteroid made from a pile of rocks may need new strategies, such as a “nuclear blast” to push it off a possible collision course with Earth, scientists said.
The research, published Monday in the journal PNAS, studied three tiny dust particles collected from the surface of an ancient 500-meter-long asteroid called Itokawa.
Analysis of these dust particles, returned to Earth by the Japanese space agency’s Hayabusa 1 probe, suggested that the asteroid could be nearly as old as the solar system itself.
Scientists, including those at Curtin University in Australia, found that Itokawa — about two million miles from Earth and about the size of the Sydney Harbor Bridge — was nearly impossible to destroy.
Last year, NASA had shown in its Dart mission proof-of-concept test that it is likely possible to effectively displace an Earth-threatening asteroid before it reaches the planet by slamming into it with a spacecraft.
But the new study indicates that it could be “really difficult” to alter the orbit of an asteroid like Itokawa, made of a pile of debris and dust, by colliding with a spacecraft.
“Unlike monolithic asteroids, Itokawa is not a single clump of rock, but belongs to the rubble family, meaning it is made entirely of loose boulders and rocks, almost half of which is empty space,” said co-author Fred. Jordan.
“The survival time of Itokawa-sized monolithic asteroids is expected to be only a few hundred thousand years in the asteroid belt,” said Dr. Jordan.
Scientists are calling for testing new strategies to push asteroids like Itokawa away from a possible collision with Earth.
“If an asteroid is detected too late for a kinetic push, we may be able to use a more aggressive approach, such as using the shock wave from a nearby nuclear detonation to push a mess asteroid off course without destroying it,” Nick said. Timms. , a study co-author.
Researchers said the impact that destroyed the asteroid’s parent rock and formed Itokawa likely happened at least 4.2 billion years ago.
The study suggests that the long survival time of an Itokawa-sized asteroid may be due to the shock-absorbing nature of debris material.
“Basically, we found that Itokawa is like a giant space cushion and very hard to destroy,” explains Dr. Jourdan.
The study used two complementary techniques to analyze the three dust particles: one method to measure whether a space rock had been shaken by a meteor impact, while another method was used to date asteroid impacts.
The durability of such debris-packed asteroids was previously unknown.
The latest finding, scientists say, jeopardizes the ability to design strategies in case such an asteroid hurtles toward Earth.
“Now that we’ve found that they can survive almost all of the solar system’s history, they should be more abundant in the asteroid belt than previously thought, so there’s more chance that if a large asteroid hurtles toward Earth, it’s going to be a mess. ,” Dr. Timms added.