The asteroid is like a giant space cushion and very difficult to destroy,
REPUBLIKA.CO.ID, JAKARTA—Asteroid Itokawa is a pile of rocky debris 500 meters long, some experts say asteroid Itokawa is pea-shaped, while others say it resembles a sea otter, complete with head, neck, and body.
Whatever Itokawa looked like, new research shows that it has remained intact—despite the incessant asteroid bombardment of the inner solar system—since its formation more than 4.2 billion years ago. These findings appear to be important for future missions designed to protect Earth from the asteroid debris pile, the researchers said.
“In short, we found that Itokawa is like a giant space cushion, and very difficult to destroy,” said Fred Jourdan, an astronomer at Curtin University in Australia and lead author of the new paper, in a statement.
The team calculated Itokawa’s age using specks of asteroid dust picked up by Japan’s Hayabusa spacecraft and brought back to Earth in 2010. By analyzing dust particles, Jourdan’s team found that Itokawa is nearly as old as the solar system itself. In the new paper, the team explains how Itokawa survived countless asteroid impacts over 4.2 billion years.
Although researchers already knew that a cataclysmic impact destroyed Itokawa’s mother, this is the first time Itokawa’s exact age and resilience have been studied directly.
Additionally, the team behind the new research studied the texture and composition of three tiny dust particles collected from the surface of Itokawa. Scientists used a radioactive dating method called argon-argon dating to date Itokawa, which they say is 4.2 billion years.
As part of the research, the team also measured how much dust particles, and later Itokawa, had been affected by the shock from the asteroid impact. For this, the researchers used another method called electron backscattering diffraction to measure the structure and orientation of crystals embedded within dust particles.
The team found that most of the dust particles were pure. This suggests they were excavated from the host asteroid, possibly when it broke up during a catastrophic collision. Scientists concluded that Itokawa was highly resistant to impact, thanks to the very porous nature of the asteroid.
As an amalgamation of leftovers from the asteroid impact, Itokawa houses boulders of various shapes and sizes that mixed together due to gravity. The pile of rubble was “made entirely of boulders and rocks, with nearly half of it being empty space,” Jourdan said in the statement.
When the asteroid hit Itokawa, the large cavities or pores between these rocks absorbed much of the energy generated, protecting the asteroid’s structure from cracking. In this way, pores help debris piles like Itokawa survive an asteroid impact at least 10 times longer than conventional single-body asteroids, also known as monoliths, the researchers found.
