Huge asteroids harder to break up than previously thought, study finds

Mindy Sparks
March 6, 2019

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.

"We used to believe that the larger the object, the more easily it would break, because bigger objects are more likely to have flaws", Charles El Mir, first author of the paper and a Ph.D.graduate from the Johns Hopkins' Department of Mechanical Engineering, said in a statement.

One of the most popular theories - as famously illustrated in 1998 Bruce Willis film Armageddon - involved blowing up the asteroid before it hits Earth.

We've seen the plot in more than one movie: An incoming asteroid is hurtling toward Earth and a fearless team of heroes is launched into space to blow it up and save the planet. A new study argues that destroying an asteroid is a complicated process which may be much harder than previously thought.

Previous understanding of asteroids was based on work at what is called "laboratory scale", meaning looking at the properties of rocks about the size of a fist. Their results suggested that the target asteroid would be completely destroyed by the impact. For their hypothetical, they imagined an asteroid approximately a kilometer in diameter (0.62 miles) hitting a 25-kilometer diameter (15.5 miles) target asteroid directly, at an impact velocity of 5 kilometers per second (11,184 MPH). Thus, modeling of asteroids previously did not account for limited speed cracks on asteroids.

The simulation was separated into two phases.


In the first phase, millions of cracks formed and rippled throughout the asteroid immediately after the collision.

The first phase of the attack shows an explosion of movement on the asteroid.

Unlike a similar study from 2000 that showed asteroids could be completely destroyed by the impact, they found that the core of the asteroid was damaged but not completely broken, researchers said.

When a science fiction plot portrays Earth in peril from a potentially devastating asteroid impact, a collection of heroes usually swoops in to save the day by detonating the enormous space rock into fragments. Though it was cracked, "the impacted asteroid retained significant strength", according to the researchers, indicating that more energy would be necessary to actually destroy the space rock.

"We are impacted fairly often by small asteroids, such as in the Chelyabinsk event a few years ago".

El Mir added that it's just a matter of time before research on asteroids become more useful than just being tackled in academic books. "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 helping us make those decisions", said KT Ramesh, director of the Hopkins Extreme Materials Institute, The Independent reports.

Other reports by Iphone Fresh

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