According to a recent study, our ultimate defense mechanism against an asteroid that crashes the earth is, after all, a viable strategy.
A late disturbance in the small body acts as a layer of defense. When small asteroids collide with Earth, they are supposed to destroy them. According to new research, such a defense is incredibly effective at protecting against asteroids when the attack is less than a year away.
“One of the challenges in assessing perturbations is that you have to model all the fragment paths, which is generally far more complicated than modeling a simple deflection,” says physicist Patrick King of Johns Hopkins University in Maryland.
“Nevertheless, we need to try to tackle these challenges if we want to assess disruption as a possible strategy.”
The models developed by the researchers examined the impact of a 1-megaton-yielding atomic bomb that hit a 100-meter (328-foot) diameter asteroid. Nuclear tests were performed between one week and six months before impact on five different asteroid orbits. If we hit the asteroid two months before its expected arrival, the destructive rain will most likely be reduced to 0.1% of the original mass. Although the asteroid is a larger space rock, if we hit it six months before its due date, we can lower its impact mass to 1%.
Although the result is reasonable, it is still a last resort that researchers do not like to count on. The biggest alternative that has been thoroughly researched and proven is to divert the asteroid away from Earth even earlier.
“We focused on studying ‘late’ disorders, which means that the affecting body is broken apart shortly before it affects,” King says. “When you have plenty of time — typically decade-long time scales — it is generally preferred that kinetic influences be used to divert the influencing body.”
Since it is impossible to predict where an asteroid’s components end up when blown up, the team used Spheral, a specialized piece of software, to estimate where these rock fragments would be transported by gravity and other factors.
If the calculations for smashing an incoming object are incorrect, a single asteroid impact could soon turn into many hits across the globe.
NASA and many other organizations are developing planetary defense systems, especially for the detection of potentially catastrophic asteroids. Longer periods are needed to improve the likelihood of diverting an asteroid.
“Our team continues to refine our modeling methods for nuclear deflection and disruption, including continuous improvements in X-ray energy deposition modeling, which set the first blow-off and shock conditions for a nuclear disruption problem,” said physicist Megan Bruck Syal of the Lawrence Livermore National Laboratory (LLNL).
“This latest paper is an important step in demonstrating how our modern polyphysical tools can be used to simulate this problem across multiple relevant physics schemes and time scales.”
The results were reported in the journal Acta Astronautica.