It’s a trope in science fiction that the best way to deal with a threatening asteroid or comet is to simply blow it to pieces. But a new study looking at actual fragments of an asteroid visited by a Japanese space mission find that the task might not be so simple.
Imagine that you are given a large sponge and asked to blow it into a hundred pieces using just a baseball bat. The job is not that easy because the sponge is porous and highly shock absorbent. It turns out that many asteroids in our solar system are similar to that sponge in that they are made of a loose amalgamation of rocks and boulders.
Asteroire Itokawa
That was the case of Itokawa asteroid sampled by the Hayabusa 1 mission of the Japanese Space Agency, which visited the rock in 2005 and returned its bounty to Earth in 2010.
“Unlike monolithic asteroids, Itokawa is not a single piece of rock, but belongs to the rubble pile family, which means that it is completely made of rocks and loose boulders, and almost half of it is empty space.”explained Fred Jourdan, a professor at Curtin University, in a statement.
Analysis
Jourdan and his colleagues analyzed small bits of debris and dust brought back from Itokawa. They were surprised by the results showing that space rock is particularly old and resilient.with an age of billions of years instead of the several hundred thousand years expected for similar asteroids.
“Such an astonishingly long survival time for an Itokawa-sized asteroid is attributed to the damping nature of the debris pile material,” says Jourdan. “In short, we found that Itokawa is like a giant space cushion and very difficult to destroy.”
Finding
The finding has implications for how we might one day protect Earth from a possible impact from a large asteroid heading our way. For one thing, the long-lived potential of debris pile asteroids means they’re likely even more common than previously thought.
That means the The idea of simply smashing an oncoming asteroid with the metaphorical equivalent of a huge baseball bat is probably not the best approach.
“The good news is that we can also use this information to our advantage,” explains co-author and Curtin Associate Professor Nick Timms. “If an asteroid is detected too late for a kinetic thrust, then we can potentially use a more aggressive approach like using the shock wave from a nearby nuclear explosion. to push a debris pile asteroid off its course without destroying it.”