Harder to Destroy Than Previously Thought
Johns Hopkins University | 2019 Mar 04
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. ...A frame-by-frame showing how gravity causes asteroid fragments to reaccumulate in
the hours following impact. Credit: Charles El Mir/Johns Hopkins University
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 ... 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. ...
A New Hybrid Framework for Simulating Hypervelocity Asteroid Impacts
and Gravitational Reaccumulation ~ Charles El Mir, K. T. Ramesh, Derek C. Richardson
- Icarus 321:1013 (2019 Mar 15) DOI: 10.1016/j.icarus.2018.12.032