從茵蔯拯救地球可能是比科學家們最先所想的更難

從茵蔯拯救地球可能是比科學家們最先所想的更難

Saving Earth From WORMWOOD Might Be Harder Than Scientists First Thought

April 16, 2019 

為何從一顆流氓小行星拯救地球可能是比我們所想的更難

Why saving Earth from a rogue asteroid might be harder than we thought

March 5, 2019

New research suggests space rocks are remarkably hard to shatter.

A frame-by-frame shows how gravity causes asteroid fragments to re-accumulate in the hours following impact.Charles El Mir / Johns Hopkins University

If humanity ever truly felt our existence threatened by an asteroid, one potential recourse would be to smash the looming space rock into pieces — but new research suggests that that approach may be less likely to succeed than people hope.

The research suggests that an asteroidwouldn't break apart as drastically as previous models suggested, and that in the aftermath of the attempted destruction, the asteroid's gravity would be strong enough to pull the fragments back together.

"It may sound like science fiction but a great deal of research considers asteroid collisions," lead author Charles El Mir, a recent doctoral graduate at Johns Hopkins University, said in a university statement. "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."

Answering those questions, unsurprisingly, would be easier if we knew more about asteroids — the authors wrote that even when it comes to asteroids that scientists have density estimates for, they typically aren't sure what their interior structure is. Nevertheless, simulations let them model asteroids with a broad range.

https://youtu.be/ZjBgljnCtWk

The results bode well for asteroids, at least. "We used to believe that the larger the object, the more easily it would break, because bigger objects are more likely to have flaws," El Mir said. "Our findings, however, show that asteroids are stronger than we used to think and require more energy to be completely shattered."

https://www.nbcnews.com/mach/science/why-saving-earth-rogue-asteroid-might-be-harder-we-thought-ncna979226?cid=sm_npd_nn_tw_mc


https://www.skywatchtv.com/2019/04/16/saving-earth-from-wormwood-might-be-harder-than-scientists-first-thought/