Research conducted by Curtin University on the durability and age of an ancient asteroid made of rocky rubble and dust revealed important results that could contribute to saving the planet if one of them launched towards Earth.
The international team studied three tiny dust particles collected from the surface of an ancient 500-meter asteroid, the rubble pile Itokawa, and returned to Earth by the Japan Space Agency’s Hayabusa 1 probe.
The results of the study showed that the asteroid Itokawa, which is two million kilometers from Earth and about the size of the Sydney Harbor Bridge, was difficult to destroy and resistant to collision.
Lead author Professor Fred Jordan, director of the Western Australian Argon Isotope Facility, part of the John D. Laiter Center and School of Earth and Planetary Sciences at Curtin, said the team also found Itokawa to be as old as the solar system itself.
“Unlike homogeneous asteroids, Itokawa is not a single mass of rock, but belongs to the rubble mound family, which means it is made entirely of rock and loose rock, and almost half is empty space,” said Professor Jordan.
It is expected that the lifetime of homogenous asteroids the size of Itokawa will be several hundred thousand years asteroid belt.
“The massive impact that destroyed the original Itokawa interconnected asteroid and formed Itokawa occurred at least 4.2 billion years ago. Such an astonishingly long survival time for an Itokawa-sized asteroid is attributed to the shock-absorbing nature of the rubble-pile material.
“In short, we found that Itokawa is like a giant space pillow, and it is very difficult to destroy.”
The team led by Curtin used two complementary techniques to analyze the three dust particles. The first is called electron backscattering and can measure whether a rock has been struck by a meteor impact. The second method – argon dating – is used to date asteroid impacts.
The durability of rubble-pile asteroids was previously unknown, said Associate Professor Nick Thames, a co-author from the Curtin School of Earth and Planetary Sciences, jeopardizing the ability to design defense strategies should one hurtle toward Earth.
Professor Thames said: “We set out to answer whether rubble-pile asteroids are shock-resistant or whether they disintegrate at the slightest blow.”
“Now that we know they can survive in the solar system for nearly all of its history, they should be much more abundant in the asteroid belt than previously thought, so there is a greater chance that if a large asteroid were hurtling towards Earth, it would be a pile of rubble.”
“The good news is that we can also use this information to our advantage — if an asteroid is detected too late for kinetic propulsion, then we can use a more aggressive approach such as using the shock wave of a nearby nuclear explosion to push the rubble-pile asteroid off course without destroying it.”
Curtin University co-authors include Associate Professors William Rickard and Celia Myers, Professor Stephen Reddy, Dr David Sachs and the distinguished John Curtin Professor Phil Bland, all from the School of Earth and Planetary Sciences.
Posted in Proceedings of the National Academy of SciencesThe study is titled “Asteroids Heap Rubble Forever”.
Jordan, Fred, the rubble pile asteroids are forever, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2214353120.
the quoteStudy Proposes (2023, January 23) Retrieved January 23, 2023, from https://phys.org/news/2023-01-rubble-pile-asteroids-impossible-destroy.html: ‘rubble pile’ asteroids
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