What happens if you shoot a cannonball at an asteroid?
Thanks to new research published Thursday in the journal Science, we now know the answer.
Scientists used the Japanese spacecraft Hayabusa2 to fire a 2-kilogram copper cannonball at a speed of 2 kilometers per second at the asteroid Ryugu, a tiny rocky body orbiting between Earth and Mars.
The cannonball, although tiny, managed to knock out a semicircular crater 14 meters wide in the surface of the asteroid. But in addition to having an impact in a real sense, the shot changed scientists' understanding of the asteroid's age, composition, and other properties.
The unprecedented results give researchers the ability to better appreciate the same details for a host of other asteroids scattered throughout the universe.
“This is all incredibly exciting,” says Patrick Michel, director of research at the French National Center for Scientific Research.
The shot allowed scientists to capture samples from the asteroid.
AXA, Kobe University, Chiba Institute of Technology, Kochi University, University of Occupational and Environmental Health.
“The surface of the asteroid is heated by solar radiation and is irradiated by the solar wind and cosmic rays, so the outer layer of the surface can be very different from the one inside,” Invers told Kobe University planetary professor Masahiko Arakawa.
He explains that organic materials and hydrated minerals on an asteroid's surface can change dramatically over time.
“We wanted to get the material without these changes, so we designed and operated a small cannon to form an artificial impact crater to expose the asteroid,” says Arakawa.
The team then developed a microsatellite to monitor the crater formation and continuous release of underground material.
“Collisions play a fundamental role in the formation and history of our solar system, starting with the formation of planets,” explains Michelle.
So far, models developed to understand the history of our solar system rely on special parameters to determine the outcome of each collision.
This means that researchers' studies of cosmic collisions are usually derived from laboratory simulations rather than direct observation.
“Scaling up laboratory results to the scale of asteroids is not trivial,” says Michel.
“The SCI experiment is the first ultra-high-speed impact experiment on such an asteroid, and it is a super-complex operation, yet it has been done with great success.”
Knowing what the Ryugu surface is made of and how impact craters are formed is critical to protecting our planet from threats from space, Michel said.
“If we want to deflect an asteroid out of orbit, we need to understand this process much better,” says Michel.
“So, while the experiment was not intended to deflect Ryugu because the impact energy is too low, its results will definitely serve as the basis for research on Earth protection.”
Sources: Photo: JAXA, Kobe University, Chiba Institute of Technology, Kochi University, University of Occupational and Environmental Health
