City-sized asteroids could be more difficult to destroy than previously thought, researchers have found.
A new study suggests the humanity-saving heroics depicted in movies such as "Armageddon" and "Deep Impact" could be even trickier than they seem.
Breaking up is hard to do
Using a new computer modelling technique, scientists at the US' Johns Hopkins University simulated an asteroid around a kilometre in diametre smashing into a 25-kilometre target asteroid.
The scenario was used in a study in the early 2000s, which saw the target asteroid destroyed.
However, with the new, more detailed computer model, the team found that the huge asteroid would retain significant strength.
"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," author Charles El Mir said.
The simulation was separated into two phases.
- The immediate impact: Millions of cracks formed throughout the asteroid and a crater was created. The new model showed that the entire asteroid is not broken by the impact, unlike what was previously thought.
- Longer-term impact: This considered the effect of gravity on the pieces that fly off the asteroid's surface after impact, with gravitational reaccumulation occurring over many hours.
The authors say the findings, to be published in Solar System studies journal Icarus, can help form asteroid deflection strategies, aid in designing asteroid mining efforts, and improve our understanding of how the solar system was formed.
One of the authors, K.T. Ramesh, director of the Hopkins Extreme Materials Institute, warned that "it is only a matter of time" before questions about how to deal with asteroids go from being academic to being applied to a real-world situation.
"We need to have a good idea of what we should do when this time comes - and scientific efforts like this one are critical to help us make those decisions," he said.