Asteroids and comets are swirling in our Solar System, containing a vast quantity of stones and also other materials. If one of those came towards us, may we avoid a collision of an asteroid with the environment?
Well, maybe. One particular asteroid however, seems to be particularly difficult to destroy.
Asteroids happen to be in space fragments of rocky debris, remnants of a more brutal past in our Solar System. If you examine them, they could reveal their physical characteristics, clues about the ancient history of the Solar System, as well as the dangers these space rocks might pose in case they impact with the Earth.
In our new study published today in the Proceedings of the National Academy of Sciences, we found that rubble pile asteroids are an extremely strong form of asteroid and difficult to destroy by collision.
Two main types of asteroid
Asteroids of the monolithic style, more or less a kilometer in diameter, are thought to have a life expectancy in the asteroid belt of just a few hundred millions years. Because of the present condition of our Solar System, that is not very long at all.
Another kind will be the rubble pile asteroids. These’re entirely comprised of numerous fragments ejected during the total or partial destruction of pre-existing monolithic asteroids.
Rubble pile asteroids, however, do not have a great deal of life, so we are not certain how durable they’re.
Abundant and sneaky rubble piles
During September 2022, the Double asteroid Redirection Test (DART) mission of NASA successfully impacted the Asteroid Dimorphos. The aim of the mission would be to figure out if we could intercept an asteroid with a small spacecraft, and it was a resounding success.
Like other recent asteroid missions by the Japan Aerospace Exploration Agency (JAXA) for the asteroids Ryugu and Itokawa and also the NASA mission to the asteroid Bennu, close-up images have shown that Dimorphos is still another rubble – pile asteroid.
Those missions confirmed to us that rubble – pile asteroids possess low density because they’re porous. They’re also abundant. As a matter of fact, they are extremely abundant, and because they’re the shattered bits of monolithic asteroids, they’re fairly small, and thus hard to recognize from Earth.
This kind of asteroids pose a significant threat to the Earth, and we need to do better understanding of them.
Learning from asteroid dust
In 2010, the Hayabusa spacecraft, designed by JAXA, returned from the 535 meter long, peanut-shaped asteroid Itokawa. The device carried more than a thousand rocks, every one as tiny as a grain of sand. They were the first samples ever returned from an asteroid!
When it ended up, the photos taken by the Hayabusa spacecraft while it was in orbit with Itokawa demonstrated for the first time the presence of rubble pile asteroids.
Early results from the team at JAXA, which analyzed the returned samples, showed that Itokawa formed after the complete destruction of a parent asteroid, that had been at least 20 kilometers across.
From our brand new analysis, we utilized two methods to assess several dust molecules from the asteroid Itokawa: The very first sends an electron beam to the particle and detects electrons that are dispersed back. It lets us know whether the rock was shattered by a meteor impact.
The next is known as argon argon dating, and it measures just how much radioactive decay takes place in a crystal using a laser beam. It informs us of the age of the meteor impact.
In the event that an approaching asteroid presents an imminent and unanticipated risk to the Earth, we will like a far more aggressive response.
For instance, we might have to utilize the shockwave from a nuclear blast in space since big explosions will be able to transfer a lot more kinetic energy to a normally cushioned rubble pile asteroid as well as nudge it out.
After that ought to we really test a nuclear shock wave strategy? That is a different matter altogether.