Let's face it. There is a good reason to fear asteroids. They're constantly grazing past Earth and they did wipe out the dinosaurs after all.
However, many believe any asteroids coming our way may be destroyed. At least, that's what sci-fi movies say. Yet, according to new research, it seems these celestial objects are tougher than we thought.
Tougher than previously assumed
Novel work by Johns Hopkins combined a new understanding of rock fracture and a new computer modeling method in order to simulate asteroid collisions in the hopes of helping with asteroid impact and deflection strategies.
"We used to believe that the larger the object, the more easily it would break, because bigger objects are more likely to have flaws. Our findings, however, show that asteroids are stronger than we used to think and require more energy to be completely shattered," said Charles El Mir, a recent Ph.D. graduate from the Johns Hopkins University's Department of Mechanical Engineering and the paper's first author.
Grasping the physical properties of rocks at a laboratory scale is easy but asteroid-sized properties are much more difficult to understand. To deal with this issue, researchers in the early 2000s created a computer model that simulated an asteroid collision. Their findings showed the asteroid would be destroyed.
"It may sound like science fiction but a great deal of research considers asteroid collisions. For example, if there's an asteroid coming at earth, are we better off breaking it into small pieces, or nudging it to go a different direction? And if the latter, how much force should we hit it with to move it away without causing it to break? These are actual questions under consideration," added El Mir.
However, El Mir put the same scenario in a new computer model called the Tonge-Ramesh model. This version accounts for the more detailed, smaller-scale processes, as well as for the limited speed of cracks in the asteroids.
"Our question was, how much energy does it take to actually destroy an asteroid and break it into pieces?" explained El Mir.
This new model showed that the entire asteroid would not be broken by the impact but instead, it would suffer a large damaged core. This strong core would continue to have a gravitational pull over the broken pieces.
As such, the pieces would all function as one giving the asteroid significant strength. The researchers concluded that much more energy would be needed to destroy asteroids. This is troublesome news for our planet.
"We are impacted fairly often by small asteroids, such as in the Chelyabinsk event a few years ago," said paper co-author K.T. Ramesh, director of the Hopkins Extreme Materials Institute.
"It is only a matter of time before these questions go from being academic to defining our response to a major threat. We need to have a good idea of what we should do when that time comes - and scientific efforts like this one are critical to help us make those decisions."
The study will be published in the March 15 print issue of Icarus.