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Space Science

Neil deGrasse Tyson On How To Stop a Meteor Hitting the Earth 520 520

An anonymous reader writes "Astrophysicist Neil deGrasse Tyson talks stopping extinction-level meteor hits: '...Here in America, we're really good at blowing stuff up and less good at knowing where the pieces land, you know...So, people who have studied the problem generally – and I'm in this camp – see a deflection scenario is more sound and more controllable. So if this is the asteroid and it's sort of headed toward us, one way is you send up a space ship and they'll both feel each other. And the space ship hovers. And they'll both feel each other's gravity. And they want to sort of drift toward one another. But you don't let that happen. You set off little retro rockets that prevent it. And the act of doing so slowly tugs the asteroid into a new orbit.'"
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Neil deGrasse Tyson On How To Stop a Meteor Hitting the Earth

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  • by paiute (550198) on Sunday March 03, 2013 @11:46AM (#43061367)

    I agree, he's great for explaining stupid shit to proles, but as far as a professional scientist goes he has very little credibility in my book.

    Great. You'd be comfortable with this future:

    Scientists: By the way, there is a huge hunk of rock that is going to hit the earth tomorrow and wipe us all out.
    Public: Wait - what? Why didn't you warn us?
    Scientists: We discussed it at length at our obscure meetings. Why should we have to take time out of our important work to explain complicated shit in your terms? Stupid proles.

  • by hawguy (1600213) on Sunday March 03, 2013 @11:47AM (#43061373)

    I agree, he's great for explaining stupid shit to proles, but as far as a professional scientist goes he has very little credibility in my book.

    It's scientists like him that are personable and able to "explain stupid shit to proles" that help keep people interested in science and help make sure the scientists in your "credibility book" get enough funding from the proles to do their work.

  • by PocketPick (798123) on Sunday March 03, 2013 @11:54AM (#43061419)

    Why do you say that? He's an established scientist and has a Bachelors in Physics and a Graduate/PH-D in Astrophysics. He's held positions at several universities and is the director of the Hayden Planetarium. Sure he goes on television more than your average physicist, but so did Carl Sagan. He's charismatic, and it works well for him. Nothing wrong with that.

    Dr. Phil is a pool of waste that puts people on television and exposes their issues to millions of viewers, for the ratings and a fat pay check. He doesn't add anything to his profession, and his discussions on television don't enlighten anyone.

    There's a huge difference.

  • by paiute (550198) on Sunday March 03, 2013 @11:58AM (#43061445)
    If you are going to use this method, then the more mass in your ship the better. Unfortunately, that means a more expensive launch. If you plan ahead, you figure out a way to accumulate debris and smaller rocks at some stable orbital point so when you need mass you can launch a light ship, go to the rockyard, and gather up more mass at reduced cost.
  • by eyenot (102141) <eyenot@hotmail.com> on Sunday March 03, 2013 @12:04PM (#43061479) Homepage

    I usually welcome hearing Tyson's latest addition to lay science understanding.

    I sort of like character-celebrity-scientists. Mister Wizard, Bill Nye, and local college instructor / news-show scientist "Chemical Kim" are just a few of the scientists I applaud for their work in bringing science to the masses as a fun and interesting subject.

    I don't like the stand-in experts like Michiu Kaku or Tyson, who take a different tack of bringing science to just a large audience, not really packaged for the masses at all, often with their own opinions added, and typically very pompously presented.

    Tyson manages to keep my respect by being relatively sane and mainstream, basing his conclusions and projections on "establishment" science.

    I can't say the same for Kaku, who I haven't heard from in awhile because I purposefully stop visiting web sites and stop listening to radio shows that give him a podium (no, this is not a viable way to get me to stop visiting /.)

    But Tyson also manages to capture my interest by doing the same thing Bill Nye does: making comments about human affairs and human nature. They both humanize science.

    But Tyson's pomposity sort of makes it hard for me to "like" him. And I just read something about him recently, so now it's like a second serving of buttered scallops when I clearly had trouble finishing the first serving.

  • by zAPPzAPP (1207370) on Sunday March 03, 2013 @12:05PM (#43061505)

    Because we are currently unable to judge the stability of the object, or it's internal mass distribution just by looking at it from long range.
    Pushing it at any point might just lead to breaking off a small piece, or the spaceship slowly sinking into and through it.
    If we miss the mass center, the push will mostly be transformed into rotation.

    All these problems are a non issue with gravitiational pull.

  • by hawguy (1600213) on Sunday March 03, 2013 @12:06PM (#43061509)

    Even if it wasn't the case, it seems to be it would be a hellva lot more efficient to use the rockets to just push the damn asteroid, rather than rely on gravity. A couple of tonnes of probe isn't going to exert much influence on a couple of hundred (thosand?) tonnes of space rock.

    You don't need much deflection if you have enough time.

  • by flyneye (84093) on Sunday March 03, 2013 @12:16PM (#43061567) Homepage

    Not Mike Tyson, it's Neil De Grasse Tyson, Miss Latella.

  • by tgd (2822) on Sunday March 03, 2013 @12:20PM (#43061597)

    I would normally agree but the whole thing sounds preposterous. The gravitational pull of a spaceship is negligible. If you're going to send a spaceship up there and let it "hover" why not just have it actually contact the meteor and use its thrusters to push it out of the way?

    The way the universe works doesn't really depend, in any way, upon you finding physics "acceptable".

    And a great many people, who clearly are vastly more knowledgeable than you, have done the math and know what they're talking about

  • by GPierce (123599) on Sunday March 03, 2013 @12:27PM (#43061647)

    Actually according to Doug Adams definitive history:

    On a planet called Golgafrincham there was an an nouncement that the planet would soon be destroyed in a great catastrophe They planned an evacuation using a group of arcs:.

    The passengers of the “A” ark were to be all the brilliant leaders, scientists, great musicians, data analysts, engineers and architects. The passengers of the “B” ark were to be all the “middle men” , marketing executives, telephone sanitizers , sales assistants and telemarketers etc. The passengers of the “C” ark were to be the real workers, construction, manufacturing and other craftsman.

    As I remember it, everyone fought for a place on the B Arc which blasted off into space programmed to land on the third planet of an obscure star at the edge of the galaxy. Shortly after its departure, they discovered it was all a mistake and the planet was not going to be destroyed.

    Golgafrincham entered into a period of exceptional peace and prosperity.

    The planet that was the destination of the B Arc had a different kind of history.

  • by Jeremi (14640) on Sunday March 03, 2013 @01:56PM (#43062329) Homepage

    .... I'm confident that we have little to worry about. Asteroids will tend to avoid our planet out of sheer embarrassment.

  • by egcagrac0 (1410377) on Sunday March 03, 2013 @04:30PM (#43063199)

    You really want to avoid any pieces going even near orbit. We have a mess of expensive stuff up there.

    It is not difficult to choose between "survival of the planet" and "doing without TV and GPS for a few years".

  • by Areyoukiddingme (1289470) on Sunday March 03, 2013 @05:25PM (#43063449)

    As mentioned elsewhere, spin. Pretty much every rock in the solar system spins, to a greater or lesser degree. Old sci fi from the masters always took this into consideration. Heinlein and Niven both wrote about eliminating spin before moving an asteroid via rockets. Their reason was because they wanted precise control of the rock, with the intention of putting it into a specific orbit. If all you want to do is miss Earth, and you don't care what the new orbit is, that's less important.

    In theory, it's possible to use direct thrust to revector an inbound rock without eliminating spin first. You just have to mate the engine and its (very large) fuel and oxidizer tanks to a spinning rock, precisely centered on its spin axis. Which means, if your engine and its fuel tanks are of any significant size, you're going to have to spin them to match precisely first. Needless to say, this isn't exactly easy.

    Once you mate an engine to a spinning asteroid, the rest is easy. The spin will even work to stabilize the thrust vector via gyroscopic effects. Regardless of the axis of spin, you never have to do more than move the rock one Earth diameter. Even if the axis of spin means your thrust is aimed directly along the asteroid's orbit, thrust will still work. You just make the rock cross Earth's orbit earlier than it would have, before Earth has shown up, thereby generating a miss. Any other axis of spin, you're pushing it aside, one direction or another.

    The only question that remains is which method is most fuel efficient and least risky. Say the rock is in a near-hit orbit, but its spin axis means you have to push it the entire diameter of Earth to generate a miss. It might then be more fuel efficient to stop the spin first, then choose your thrust axis yourself, so you only have to move the rock's orbit a small fraction of Earth's diameter in the other direction to generate a miss. So is it more fuel efficient to eliminate the spin and push any direction you want, or to leave it spinning and push along the spin axis? You'd have to do some math to find out, and the answer varies depending on the rock. You also have to factor in the risk of failure. Are you more likely to fail if you have to mate two engines to the rock (one for spin reduction, the other for adjusting direction) or just one?

    The gravity trick is intended to avoid all that. No mating required, so all you have to do right is navigate a spacecraft. Something we're getting fairly good at. Magnetic coupling is less appealing for the same reason: more systems with more parts doing something we've never done before. And we REALLY don't want to screw this up. We're talking about the end of civilization, remember, not to mention an extinction event for many species.

    And that, ultimately, is the reason for Neil deGrasse Tyson's answer: it's the most pragmatic method. All we have to do is something we already know how to do. Nothing new, anywhere, thereby minimizing the risk of failure.

    If that asteroid mining company actually gets to the stage of mating a rocket to a rock and moving it for mining purposes, then everything is different. With proven expertise in rock-rocketry, that becomes the new best answer.

  • by Old Wolf (56093) on Sunday March 03, 2013 @05:46PM (#43063561)

    But Tyson's pomposity sort of makes it hard for me to "like" him..

    They're fine as long as they don't get uppity, eh?

  • by Goaway (82658) on Sunday March 03, 2013 @06:58PM (#43063817) Homepage

    Appeal to authority is, in many, many cases, a perfectly valid argument. Appeal to authority is the entire reason our society can even function at all. We offload complicated decisions to people who are better at them than us.

    And in this case, it is once again correct. Neil deGrasse Tyson does indeed know what he is talking about. The gravity tractor idea has been around for a long time, and in theory works just fine.

I have the simplest tastes. I am always satisfied with the best. -- Oscar Wilde