Scientists have uncovered some of the secrets of asteroids by studying tiny specks of dust from an asteroid called Itokawa. The research, published in the journal Proceedings of the National Academy of Sciences, shows that these space rocks are vastly older than previously thought and much tougher than expected. This new information could mean that we need bolder ways to prevent catastrophic collisions with Earth.
The three samples were collected in 2005 from the peanut-shaped Itokawa, which is located some 300 million kilometers from Earth. The Japanese spacecraft Hayabusa returned the samples to Earth, along with hundreds of other particles from Itokawa, and scientists have been analyzing them for clues ever since.
The team analyzed crystal structures in the samples, looking for deformations caused by the impact that created Itokawa. They also dated the samples by measuring the decay of potassium into argon. The methods suggest that Itokawa was formed by an asteroid collision at least 4.2 billion years ago, which is ten times older than solid asteroids of similar size are predicted to be.
These findings suggest that rubble-pile asteroids are so resilient to the constant battering they face that they are likely to be much more abundant than previously assumed. This means that we may need new ways to tackle such asteroids on a collision course with Earth. NASA’s recent DART test showed that asteroids like Itokawa can be nudged off course, but that would likely require a lead time of several years. An asteroid just weeks from colliding with Earth would require a different approach, and scientists argue that a nuclear blast might be needed.
It’s important to note that these conclusions are drawn from tiny specks of dust, but each particle is analyzed at the atomic level. “We can get big stories like that out of (something) very, very small, because those machines, what they’re doing, is the measuring and counting of atoms,” said lead researcher, Professor Fred Jourdan of Curtin University’s School of Earth and Planetary Sciences.