Destroying an asteroid flying toward Earth will be more difficult than previously thought
Using a new computer modeling method and recent findings on rock fracture processes, researchers at Johns Hopkins University have demonstrated that destroying an asteroid on a collision course with Earth will be more difficult than previously thought.
The threat from an incoming asteroid is a popular theme of Hollywood productions. In the movies, brave heroes spring into action and fly to meet the space rock to destroy it and save the Earth from annihilation. Such a scenario can be seen, for example, in the movie Armageddon. But as researchers at Johns Hopkins University (JHU) are finding, destroying an asteroid may be more difficult than previously thought.
Scientists in earlier calculations estimating the power needed to successfully smash a large asteroid also used computer models. However, the new model presented by the JHU researchers took into account a variable thatórą earlier models overlooked. This refers to the rate at which cracks propagate through the asteroid after it hits it.
The findings, whichóre will be published on March 15 in the periodical „Icarus”, may pomóc in developing effective defense strategies against asteroid impactsów. They can róalso pomóc to better understand the formation processes of the Solar System.
– Until now, we believed that the larger the object, the easier it is to destroy, because larger objects have more weak punków. However, our findings show that asteroids are harder than we thought and require much more energy to destroy them – said Charles El Mir, head of theówny author of the publication.
JHU scientists began by creating a computer model thatóry simulated the effects of an asteroid with a diameter of one kilometer hitting another with a diameter of 25 kilometersów. The impact was simulated at a speed of five kilometersów per second. The same scenario was tested in earlier computer models. They took into account many factorsów: mass, temperature or fragility of the material, and the result indicated that in such a collision the larger asteroid would be completely destroyed.
By taking a closer look at the minute changes in the asteroid’s structure, scientists have developed a more accurate picture of the post-impact situation. In the new model, El Mir and his coóDerek Richardson and K. T. Ramesh took into account more detailedół smaller-scale processes, whichóre occur during asteroid collisions.
Previous models did not adequately account for the limited velocity of cracks in asteroids. The new model, called the Tonge-Ramesh model, was able to give researchers a more accurate picture of what might happen during such a collision. The results showed that a larger asteroid, instead of being completely destroyed as previous models indicated, would only be partially destroyed.
The new model suggests that gravity can pomóc asteroids to stay in one piece even after a strong impact and that much more energy is needed to completely destroy a space rock.
The simulation was divided into two phases: a fragmentation phase on a shortótion on a short time scale, and a phase of reaccumulation under the influence of gravity occurring on a longer time scale. The first phase considered processes thatóre start immediately after the asteroid’s impact, processes that occur in fractions of a second. The second long-term phase takes into account the effect of gravity on the rock fragments formed during the impact, as well as the gravitational re-accumulation occurring for hours after the impact. Below, the two phases shown on the krótic video films.
As the simulation indicated, the first phase created millions of cracks in the asteroid. This phase examined the individualólne fractures and predicted ogólne patterns of their propagation. The new model showed that the asteroid was only partially destroyed, contrary to what was previously thought. Instead, the damaged asteroid nucleus exerted a strong gravitational influence on the fragments formed in the second phase of the simulation.
According to the results, the final impact was not just a pile of debrisów – a collection of small fragmentsóin loosely coupled gravitational. The impacted asteroid was not completely destroyed, indicating that much more energy is needed to remove the asteroid threat.
– It may sound like science fiction, but many of the studies address asteroid impacts. For example, if there is an asteroid that is on a collision course with Earth, would it be better to smash it into small pieces or change its flight trajectories? And if the response is the second option, how much energy is needed to change its trajectory without destroying it? It’s someóre of the aspects we are consideringów,” explained El Mir.
– Quite often we are hit by small asteroids, such as in Chelyabinsk a few years ago. It’s only a matter of time before our academic musings become the answer to a serious threat. We need to know exactly what we should do when that time comes, and such research is crucial for decision-making – emphasized Ramesh.