A popular theme in the movies is that of an incoming asteroid that could extinguish life on the planet, and our heroes are launched into space to blow it up. But incoming asteroids may be harder to break than scientists previously thought, finds a Johns Hopkins study that used a new understanding of rock fracture and a new computer modeling method to simulate asteroid collisions.
The findings, to be published in the March 15 print issue of Icarus, can aid in the creation of asteroid impact and deflection strategies, increase understanding of solar system formation and help design asteroid mining efforts.
“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,” says Charles El Mir, a recent Ph.D graduate from the Johns Hopkins University’s Department of Mechanical Engineering and the paper’s first author.
Researchers understand physical materials like rocks at a laboratory scale (about the size of your fist), but it has been difficult to translate this understanding to city-size objects like asteroids. In the early 2000s, a different research team created a computer model into which they input various factors such as mass, temperature, and material brittleness, and simulated an asteroid about a kilometer in diameter striking head-on into a 25-kilometer diameter target asteroid at an impact velocity of five kilometers per second. Their results suggested that the target asteroid would be completely destroyed by the impact.
In the new study, El Mir and his colleagues, K.T. Ramesh, director of the Hopkins Extreme Materials Institute and Derek Richardson, professor of astronomy at the University of Maryland, entered the same scenario into a new computer model called the Tonge-Ramesh model, which accounts for the more detailed, smaller-scale processes that occur during an asteroid collision. Previous models did not properly account 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?” says El Mir.
The simulation was separated into two phases: a short-timescale fragmentation phase and a long-timescale gravitational reaccumulation phase. The first phase considered the processes that begin immediately after an asteroid is hit, processes that occur within fractions of a second. The second, long-timescale phase considers the effect of gravity on the pieces that fly off the asteroid’s surface after the impact, with gravitational reaccumulation occurring over many hours after impact.
In the first phase, after the asteroid was hit, millions of cracks formed and rippled throughout the asteroid, parts of the asteroid flowed like sand, and a crater was created. This phase of the model examined the individual cracks and predicted overall patterns of how those cracks propagate. The new model showed that the entire asteroid is not broken by the impact, unlike what was previously thought. Instead, the impacted asteroid had a large damaged core that then exerted a strong gravitational pull on the fragments in the second phase of the simulation.
The research team found that the end result of the impact was not just a “rubble pile” – a collection of weak fragments loosely held together by gravity. Instead, the impacted asteroid retained significant strength because it had not cracked completely, indicating that more energy would be needed to destroy asteroids. Meanwhile, the damaged fragments were now redistributed over the large core, providing guidance to those who might want to mine asteroids during future space ventures.
“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,” adds El Mir.
“We are impacted fairly often by small asteroids, such as in the Chelyabinsk event a few years ago,” says Ramesh. “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 Latest on: Asteroids
via Google News
The Latest on: Asteroids
- Scientists to use near-Earth object telescope to observe cosmic mergerson August 16, 2019 at 9:45 am
Aug. 16 (UPI) --Scientists have reprogrammed the Catalina Sky Survey's near-Earth object telescopes to look for both asteroids and cosmic mergers. "Catalina Sky Survey has all of this infrastructure ...
- Best of both worlds: Asteroids and massive mergerson August 16, 2019 at 6:55 am
The race is on. Since the construction of technology able to detect the ripples in space and time triggered by collisions from massive objects in the universe, astronomers around the world have ...
- Why Does Jupiter Get Hit By So Many Objects In Space?on August 15, 2019 at 11:06 pm
After all, if you exclude the Sun, Jupiter is as massive as all the remaining planets, moons, asteroids, Kuiper belt and Oort cloud objects in our Solar System combined. Or, perhaps more prosaically, ...
- New date for 'Late Heavy Bombardment' may change life's timeline on Earthon August 15, 2019 at 7:53 am
The solar system once experienced a meteor shower of epic proportions: Asteroids whizzed around the inner planets, crashing down in a rain of fire that left their surfaces scarred for billions of ...
- The 10 biggest asteroids that could crash into Earth in 2019on August 14, 2019 at 9:10 pm
At any given moment, there are hundreds of asteroids in our solar system that could potentially crash into the Earth. Some scientists even think that it’s all but inevitable that an asteroid will ...
- Recent Asteroid Flybys - Unusual, But Expectedon August 14, 2019 at 1:58 pm
In the fourth week of July, three small asteroids made flybys of Earth. 2019 OD passed just within one lunar distance, the average distance from Earth to the Moon, on July 24. A bit later on July 24; ...
- A flashing mystery is unfolding at the center of the Milky Wayon August 14, 2019 at 12:15 pm
Known as Sagittarius A* (which is pronounced “Sagittarius A star”) or Sgr A* for short, it creates a tumultuous environment, whipping stars around at millions of miles per hour and shredding any ...
- Asteroids Will Wipe Out All Life On Earth, Scientists Warnon August 13, 2019 at 10:09 pm
Famous astrophysicist Neil deGrasse Tyson and cosmochemist Natalie Starkey warned that although asteroids may have brought life on Earth, they could also spell the end for the entire planet following ...
- Asteroid path 2019: Biggest asteroids and near misses to pass Earth projected THIS YEARon August 13, 2019 at 4:00 pm
The idea of an asteroid slamming into Earth has long been the preserve of science fiction. However Earth’s pockmarked surface are an enduring testament that direct – and sometimes calamitous – ...
- 6 asteroids to zip past Earth this month -- and 1 is giganticon August 5, 2019 at 1:08 pm
STATEN ISLAND, N.Y. -- Six asteroids are heading toward Earth in the next few weeks, and one is reportedly bigger than the Empire State Building. But don’t panic -- the asteroids aren’t expected to ...
via Bing News