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Deflecting an Asteroid Will Be Harder Than Scientists Thought (upi.com)
schwit1 shares a report from UPI: According to new asteroid collision models designed by scientists at Johns Hopkins University, deflecting a large rock headed for Earth will be harder than previously thought. Using the most up-to-date findings on rock fracturing, researchers developed computer models to more accurately simulate asteroid collisions. For the newest study, scientists decided to divide the model into two phases. Phase one modeled the immediate fracturing that happens in the wake of a collision -- the processes that play in a matter of seconds. The second phase simulated the gravitational re-accumulation process that happens over the course of several hours or days.
The first phase of the updated model showed a large asteroid is not destroyed by a much smaller asteroid. Instead, millions of cracks form throughout, the core fractures and a crater is left behind. During phase two, the fractured core exerts a strong gravitational pull on the smaller pieces of debris and shrapnel broken during the impact. Because the asteroid did not crack completely during phase one, the space rock retained significant strength. If scientists are going to develop an asteroid deflection strategy that can actually work, they need to know how much force it really takes to destroy or deflect one. The latest study -- published in the newest issue of the journal Icarus -- showed it's more force than was originally thought.
The first phase of the updated model showed a large asteroid is not destroyed by a much smaller asteroid. Instead, millions of cracks form throughout, the core fractures and a crater is left behind. During phase two, the fractured core exerts a strong gravitational pull on the smaller pieces of debris and shrapnel broken during the impact. Because the asteroid did not crack completely during phase one, the space rock retained significant strength. If scientists are going to develop an asteroid deflection strategy that can actually work, they need to know how much force it really takes to destroy or deflect one. The latest study -- published in the newest issue of the journal Icarus -- showed it's more force than was originally thought.
If a large asteroid on a collision course with Earth is fractured, that just turns it into a bunch of little asteroids that will hit Earth.
So the Earth doesn't get shot with a 12-gauge slug, it gets blasted with birdshot. Either way, anything on the surface is completely fucked.
Isn't the goal to change the course of the asteroid?
"Ten days? Have a world-wide "End of the World" party." - Including watching the 1999 Canadian film "Last Night"... Plot: In Toronto, a group of friends and family prepare for the end of the world, expected at midnight as the result of a calamity that is not explained, but which has been expected for several months ... In 2014, Colin McNeil of Metro News wrote "Last Night is perhaps the most upbeat end-of-the-world movie you’ll ever see." ...
Rogert Ebert's review ... Note: On a talk show in Toronto, I [Roger Ebert] was asked to define the difference between American and Canadian films, and said I could not. Another guest was Wayne Clarkson, the former director of the Toronto Film Festival. He said he could, and cited this film. "Sandra Oh goes into a grocery story to find a bottle of wine for dinner," he said. "The store has been looted, but she finds two bottles still on the shelf. She takes them down, evaluates them, chooses one, and puts the other one politely back on the shelf. That's how you know it's a Canadian film."
Indeed. If it takes more force than originally estimated to fracture an asteroid, that's a *good* think - it makes deflecting it easier. Fracturing is one of the things most asteroid-avoidance plans want to avoid.
You only want to shatter it (and only maybe) if it's already too late to deflect it - doing so turns a rifle slug who's impact point we can predict, into a shotgun blast that'll hit all over the place, but probably some of it will miss, and more of it will burn up in the atmosphere so that individual impacts are less damaging. The overall effect is likely to be more devastating though - unless the original impact point would have been something especially bad.
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Go take a look at the long list of asteroids that have passed frighteningly close to Earth, that we didn't see until they were already past.
The problem is that we have a 50/50 chance that the asteroid will approach us from inside our orbit, in which case the side facing us will not be lit by the sun, rendering it nearly invisible (though the IR telescopes designed specifically for spotting asteroids by their heat signature will do better)
--- Most topics have many sides worth arguing, allow me to take one opposite you.
I'm trying to figure out what you might mean, given the fact that asteroids are typically invisible to radio telescopes, and the amount of radio power you'd need to broadcast to illuminate even a tiny sliver of the night sky brightly enough to spot an asteroid from half a billion km away would be mind-boggling.
--- Most topics have many sides worth arguing, allow me to take one opposite you.