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No Bomb Powerful Enough To Destroy an On-Rushing Asteroid, Sorry Bruce Willis 352

Posted by samzenpus
from the big-bomb dept.
coondoggie writes "Maybe it's the doom predictions about the end of the Mayan calendar this year, or maybe these guys are obsessed with old Bruce Willis movies. Either way a class of physics students from the University of Leicester decided to evaluate whether or not the premise of Willis' 1998 'Armageddon' movie — where a group of oil drillers is sent by NASA to detonate nuclear devices on an asteroid that threatens to destroy Earth — could actually happen. The students found it would take a bomb about a billion times stronger than the biggest bomb ever detonated on Earth."
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No Bomb Powerful Enough To Destroy an On-Rushing Asteroid, Sorry Bruce Willis

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  • by Anonymous Coward on Thursday August 09, 2012 @03:12AM (#40928223)

    Armagedon is not that old at all.. uhmm.. ohmm...

    Fuck, get of my lawn

  • by Anonymous Coward on Thursday August 09, 2012 @03:13AM (#40928229)

    We have a bomb that big! OoooOOOOOooh!

  • by Anonymous Coward on Thursday August 09, 2012 @03:16AM (#40928247)

    is it me or did the class get it wrong, it was never about destroying an asteroid, it was about splitting it up in pieces or nudging it out of the earth direction

    • by ArcherB (796902) on Thursday August 09, 2012 @03:18AM (#40928271) Journal

      is it me or did the class get it wrong, it was never about destroying an asteroid, it was about splitting it up in pieces or nudging it out of the earth direction

      Exactly what I was thinking: Define "destroy". Do they mean completely vaporize or just something that will do the job?

      • by Rei (128717) on Thursday August 09, 2012 @05:57AM (#40929087) Homepage

        Exactly what I was thinking: Define "destroy". Do they mean completely vaporize or just something that will do the job?

        Yes, if only there was a way to know what the students meant, like, oh I don't know, reading the article?

      • by CrimsonAvenger (580665) on Thursday August 09, 2012 @07:30AM (#40929507)

        Exactly what I was thinking: Define "destroy". Do they mean completely vaporize or just something that will do the job?

        What they mean is "break an asteroid the size of Ceres into two pieces, both of which would miss the planet, assuming the asteroid (the size of Ceres) were only noticed heading towards Earth at about the time the guys in the movie noticed it".

        And while it is no doubt true that it would take that much energy to break Ceres in half if it were that far away, this says nothing at all about more, shall we say, "realistic" scenarios involving asteroids small enough to actually get that close before we notice them.

        Or for that matter, asteroids that big as far away as we'd notice them....

    • by symes (835608) on Thursday August 09, 2012 @03:22AM (#40928293) Journal

      Indeed. A small nudge, if applied when the asteroid is still some distance from Earth, could have a considerable impact on it's trajectory. That would make an interesting project, simulating the relationship between time to asteroid, payload, asteroid mass and what not to determine how quickly we would need to react.

      • by hazem (472289) on Thursday August 09, 2012 @04:56AM (#40928787) Journal

        Arthur C. Clarke's book, "The Hammer of God" was about this exact topic. It featured all kinds of neat furistic technology, like making a huge detonation in the solar system to emit a huge burst of EM radiation to find dark asteroids, and trying to put a mass driver on an asteroid to nudge it off course. It also had a great depiction of a lunar marathon.

        All in all, I thought it was a pretty enjoyable read.

        • by Rei (128717) on Thursday August 09, 2012 @06:06AM (#40929149) Homepage

          One of the simplest ways to slowly nudge an asteroid off course is simply to have your spacecraft hover near it, with its (low thrust/high ISP) jets askew (instead of pointing straight at the asteroid). You don't need to be physically attached to an asteroid to tow it; gravity can be your "cable".

          Another even slower but potentially even simpler way proposed to move an asteroid out of an intercept course is to "paint" it (basically, detonate one or more bombs of reflective dust) on particular locations and use the change in solar radiation pressure to do the work for you.

      • That would make an interesting project, simulating the relationship between time to asteroid, payload, asteroid mass and what not to determine how quickly we would need to react.

        Interesting project to amuse a physics undergrad for a weekend, I guess.

    • by Anonymous Coward on Thursday August 09, 2012 @03:58AM (#40928471)

      Also why not do a case study for thresholds where the bomb might be useful. An asteroid that threatens the planet may not be stopped, but something that could wipe out a metropolitan area and cause trillions of dollars of damage might be a size that could be. An asteroid on that scale may do less or no damage if it could be broken into small enough pieces before it hits the atmosphere.

      Also anyone remember that Deep Impact mission with the copper slug slammed into an asteroid some years back? That inert chunk of metal also happened to be very close to the volume and mass of a common nuclear warhead in the U.S. arsenal. (Looking at those numbers, it doesn't appear too random.) It seems somebody was seriously considering the idea.

    • by pantaril (1624521)

      is it me or did the class get it wrong, it was never about destroying an asteroid, it was about splitting it up in pieces or nudging it out of the earth direction

      Indeed drilling a hole to the center of the asteroid and blowing it from inside is inefficient and stupid. The best way would be to aply force to the side of the asteroid, so its trajectory would change to non-coliding with earth. It can be some king of one-time explosion, or it could be small but perpetual force like ion-drive powered space-craft pushing to the side, or even series of mirrors orbiting the asteroid and reflecting sun-shine to its side for prolonged period of time.

      See http://www.aljazeera.co [aljazeera.com]

      • by arth1 (260657) on Thursday August 09, 2012 @04:43AM (#40928721) Homepage Journal

        Indeed drilling a hole to the center of the asteroid and blowing it from inside is inefficient and stupid. The best way would be to aply force to the side of the asteroid, so its trajectory would change to non-coliding with earth.

        I'd think that for a small body, the two are the same. A reason for drilling a deep hole first would be to get a much more precise vector for pushing the asteroid.
        Sure, you lose a lot of energy that way, but you lose an awful lot with a surface blast too, where more than half the blast force won't hit the asteroid at all. There's no way of making a nuclear explosion into a shaped charge without using the environment to shape it.

        • Sure, you lose a lot of energy that way, but you lose an awful lot with a surface blast too, where more than half the blast force won't hit the asteroid at all.

          Use something like a penetrating anti-bunker bomb, only with a nuclear warhead (there are bombs like this, and the surface material should be soft). Let it explode slightly underground. A significant mass gets vaporized, and it escapes through the hole on the top. The crater just being formed acts as a nozzle. An inefficient one, but with a nuke, you have a lot of energy to spend. Using the surrounding asteroid mass as the reactive matter increases the impulse, compared to a contact detonation or a proximit

      • by letherial (1302031) on Thursday August 09, 2012 @04:58AM (#40928797)

        That wouldnt be a good movie.

        Its either.
        A. Sir! we got a astroid that is going to hit earth with in 20 years.
                  Good find private, now send up the ION maker and point at it for the next 15 years, that should move it away to safely pass by

        OR
        B. Sir we got a asteroid that will hit us in the next few months
                  Good find private, we will nuke the bastard, but first we must make some realy cool ships, get a few heroes and they can go drill the hole in the asteroid and really get it good.

        A is good if it realy happens, B is good for the movie theater...

      • by 1u3hr (530656)

        Indeed drilling a hole to the center of the asteroid and blowing it from inside is inefficient and stupid.

        It was a Michael Bay movie. So what else could it be?

        There is hardly a scene in the film that makes sense.

        They needed an excuse to use oil roughnecks IN SPACE! and a deadline, and a bomb.

        "Deep Impact" was only slightly more plausible. Morgan Freeman and Robert Duvall were impressive, the rest, Spielbergian cloyingly cute kids and family values. So actually I'd much rather watch "Armageddon" again, dumb as it is.

    • by mosb1000 (710161) <mosb1000@mac.com> on Thursday August 09, 2012 @04:24AM (#40928643)

      If you'd read the article, you'd know that the calculation was to determine how powerful the explosion would need to be to split the asteroid in half so that the two pieces would pass by the earth. Basically, the same thing that was done in the movie. Only, in their calculation, the explosion occurred when the asteroid was still 8 billion miles away.

    • by tinkerton (199273)

      splitting up to pieces is a bad idea too. Many pieces will (generally speaking) be large enough to cause devastation, their direction will be unpredictable and the chances of getting hit will increase. You want to nudge it, and using atomic bombs for that is a bad idea. Again.

      • You want to nudge it, and using atomic bombs for that is a bad idea. Again.

        Why?

    • by Taco Cowboy (5327)

      is it me or did the class get it wrong, it was never about destroying an asteroid, it was about splitting it up in pieces or nudging it out of the earth direction

      Can't remember where I read it, but the result of splitting up a comet by detonation could be even more catastrophic to the inhabitants on Planet Earth

      The reason they say was that many of the split-up fragments, hundreds (or even thousands) of them, raining down on Earth, would create even more damage to our planet, than one single M-F hit

      As I am not a planetary scientist, I dunno if TFA that I read made any sense or not

    • by AK Marc (707885)
      http://xtiner18.edublogs.org/2010/09/18/armageddon-physics/ [edublogs.org]

      I did a quick search and found better analysis of the movie. The students fail, even if they pass the class.
    • is it me or did the class get it wrong, it was never about destroying an asteroid, it was about splitting it up in pieces or nudging it out of the earth direction

      It's you. The class did model it correctly: destroying the asteroid by splitting it into 2 halves, and nudging them so that each passes the earth on opposite sides.

      In reality, the picture is actually much more pessimistic than modeled: you wouldn't manage getting exactly two pieces.
      If you get more than 2 pieces, the middle pieces would still hit earth and wreak quite some havoc.
      If you do manage to get only 2 pieces, but they are not equal sized, the lighter one would clear the earth by a bigger margin th

  • I'm not exactly for challenging the Department of "Defense" on this one.
  • It has been well known we can't just blow it up for a while. However all we need is to bump it off course. Something a very powerful nuclear bomb may be able to do

  • by erikkemperman (252014) on Thursday August 09, 2012 @03:17AM (#40928265)

    "The biggest bomb ever detonated on earth" is a damn sight smaller than the biggest one ever built... Just sayin'.

    • by Anonymous Coward on Thursday August 09, 2012 @03:28AM (#40928331)

      The biggest one ever detonated, the so called "Tsar Bomba", was 50 megatons of TNT. It could have been made 100 MT, but was scaled back to reduce fallout, and was therefore a very clean bomb for its size.
      There was however no point in building bombs of this size, so no one has attempted it since, opting instead for clusters of smaller bombs to carpet an area or using modern targeting to accurately take out small targets with great precision,
      Bombs that big where shere lunacy and just a demonstration of power.

      • by Tore S B (711705) on Thursday August 09, 2012 @04:01AM (#40928491) Homepage

        Actually, there was a real, sensible (as things go in the field of nuclear deterrent) reason for them: The USSR did not at the time have anything that could deliver a payload with precision. Plus, they used big and slow bombers, which made it possible to intercept them. Thus, they employed a lesson from Ken Thompson in the future: "When in doubt, use brute force". :)

        The design was not scaled down as such - it was a 100MT bomb; they simply substituted lead for U-238 in the tamper.

    • You're wrong. Just sayin'.

      "The biggest bomb ever detonated on earth" is the biggest one ever built - the full yield version was never built.

  • how they did it (Score:5, Informative)

    by phantomfive (622387) on Thursday August 09, 2012 @03:18AM (#40928275) Journal
    I'm not sure why this is news, but here's what they calculated:

    The students devised a formula to find the total amount of kinetic energy needed in relation to the volume of the asteroid pieces, their density, the clearance radius (which was taken as the radius of Earth plus 400 miles), the asteroid's pre-detonation velocity, and its distance from Earth at the point of detonation. Using the measurements and properties of the asteroid as stated in the film, the formula revealed that 800 trillion terajoules of energy would be required to split the asteroid in two with both pieces clearing the planet. However, the total energy output of Big Ivan "only comes to 418,000 terajoules. The asteroid is approximated as a spherical object 1000km in diameter

    • Re: (Score:3, Informative)

      by loufoque (1400831)

      I'm not a bomb geek but even I know that Big Ivan is not the largest bomb ever made.

      • Well, I am a bomb geek and Tsar Bomba (the bomb geeks name for Big Ivan), or at least the 50MT version, is in fact the largest bomb known to be ever made. Only a single 50MT device was ever assembled, and no full yield (100MT) was ever assembled.

        • by loufoque (1400831)

          I had heard of it as Tsar Bomba, and didn't know Big Ivan was another name for it. My bad.

      • I'm not a bomb geek but even I know that Big Ivan is not the largest bomb ever made.

        And that relates how to an article quoting the "biggest bomb ever detonated on Earth."

        Which is most definitely Big Ivan.

      • by Anonymous Coward

        Not sure if this is what you are talking about, but in The Fog of War (excellent piece of film, please watch it if you haven't) Robert McNamara claims (and quite emphatically at that) that during his tenure as Secretary of Defense, the US tested a 100MT device in the atmosphere.

        It's true that he was getting on in years, but he nevertheless seemed to be more lucid than, say, most everyday people, and there doesn't seem to be much point to making such a thing up.

    • Why would we need to deflect it? The assumptions were that the movie was correct, not that the earth is rendered safe from planetary wide extinction. You wouldn't need to deflect the asteroid at all for that.

      A sufficiently sized bomb drilled into the middle of the asteroid would with ease break it up into smaller chunks. All those chunks individually would still hit the planet, but if the chunks are sufficiently small you dramatically increase their surface area and the amount they burn up as they enter the

      • by mosb1000 (710161)

        You're describing Deep Impact [wikipedia.org].

      • by TheLink (130905)
        Because deflecting an asteroid that's far away from earth is easier than reliably blasting it to small enough bits.

        Think of how much force it takes to nudge a cue ball away from its original destination. Compare with the force it takes to blast a rock to small bits.

        If a big asteroid is already too close to nudge away, we're screwed.
      • by rts008 (812749)

        You are begging the question.

        You are making far too many assumptions with your argument.

        A sufficiently sized bomb drilled into the middle of the asteroid would with ease break it up into smaller chunks.

        A 'shaped charge' that exploits a weakness detected at farther away than we are currently able too, by magnitudes of order, are no help, realistically.

        What we need to do, is fund advanced detection of these threats, if, and when, they are perceived by 'Joe Six-pack"; or make that happen...

        I won't even bother with the rest of your assumptions, they are too ludicrous to even comment on, based on the first assumption.

      • I think you're basically arguing that it's better that the shotgun pointed at you from two foot away be loaded with shot instead of a deer slug.
      • by tinkerton (199273)

        Just imagine breaking up an asteroid of 1km diameter in asteroids that all have diameters of less than 50m, with a single bomb. I don't think it'll work. But it does lead to the idea that mass drivers could come in two variants. The efficient one that keeps the asteroid whole, and the wasteful one that just throws aways rocks at escape speed.

  • The definition of "big enough" is apparently "big enough to split a 1000km diameter spherical asteroid in two, and with enough force that the trajectory of both pieces misses the earth". I haven't seen the movie - is that what they did?

    It seems to me, though, that the goal should be to break up an approaching asteroid into small enough pieces so the atmosphere can do most of the dirty work for us. Deflecting the asteroid doesn't seem very feasible unless we detect it long before it approaches earth (and the

    • by Kupfernigk (1190345) on Thursday August 09, 2012 @04:00AM (#40928487)
      The last thing you want is lots of pieces - there's something called gravity which would cause them to re-agglutinate on the rest of the journey. Breaking up an asteroid takes far more energy than deflection, as should be obvious-despite the current illiteracy, it takes far less energy to brake a car than it does to break it up. Of course Hollywood wouldn't want deflection because there's nothing to see on screen - but deflecting it into a safe orbit would be much safer because you only have to predict the track of one object, not millions of small ones with different trajectories.
      • by mosb1000 (710161)

        it takes far less energy to brake a car than it does to break it up

        That depends on how fast it's going. . .

      • by Twinbee (767046)
        If they are smaller pieces though, they'll break up in the Earth's atmosphere must more easily surely? If they were really small, they'd presumably break up completely?

        Also, wouldn't an explosion spray all the pieces in 360 degree directions, with many bits going back off into space.
  • by Anonymous Coward on Thursday August 09, 2012 @03:29AM (#40928339)

    Forget Bruce Willis, you just have to land Chuck Norris up there and have him stomp his foot once.

  • by bjdevil66 (583941) on Thursday August 09, 2012 @03:31AM (#40928355)

    Plot points based in hard science aren't exactly Michael Bay's MO...

  • by Bongoots (795869) * on Thursday August 09, 2012 @03:34AM (#40928369)

    This is the real paper, coming in at only 2 pages it's a light read: https://physics.le.ac.uk/journals/index.php/pst/article/viewFile/390/243 [le.ac.uk]

    You weren't going to RTFA anyway, now were you?..
    --

    P1_1 Could Bruce Willis Save the World?
    Back A, Brown G, Hall B and Turner S
    Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH.
    November 1st, 2011

    Abstract
    The film Armageddon (1998) puts forward the possibility of using a nuclear weapon buried deep within an Earth-bound asteroid to split the asteroid in two, each half clearing opposite sides of the Earth with only relatively minor damage. This article investigates the feasibility of such a plan and shows that even using the largest nuclear weapon made to date, the bomb comes over 9 orders of magnitude short of the yield required.

    [...]

    • by Chewbacon (797801)
      Perhaps this would work if the asteroid was already fractured and prone to shatter? Just a thought, but the chances of that are probably pretty slim.
  • We've known for a long time that the guys in Hollywood have been pretty bad at math, though usually they are only out by a factor of a million.

  • Scenario : there is 5 years warning, and the asteroid is 10 km is diameter (the size of the one that wiped out the dinosaurs).

    Could we deflect it? Assume that the mission to intercept the asteroid reached it 2 years before impact.

    I kind of feel like there would be a way. In this scenario, ALL the resources are going to solving the problem. At least 50 trillion dollars or more. Most other activities are suspended in the western world and china. A salt-water fission rocket or something ought to be powerf

  • No worries! (Score:4, Funny)

    by EzInKy (115248) on Thursday August 09, 2012 @03:46AM (#40928419)

    Everyone knows that in such an event Sam will open a hyperspace window and the asteroid will fall right through.

    "You know, you blow up one sun and suddenly everyone expects you to walk on water."
              Lt. Col. Samanth Carter

    • You only need to open hyperspace windows if the asteroid has a high concentration of naquadah, else a Mk IX gate buster aught to vaporize everything in a 100 mile radius. So that's solved for anything up to 100 miles.

  • Blowing up asteroids is oldschool. All the cool kids these days just open a hyperspace window and fly them safely through the planet and then conveniently forget that we have a massive object rich with valuable minerals in orbit around Earth for the rest of the series.

  • by Fusselwurm (1033286) on Thursday August 09, 2012 @04:10AM (#40928557) Homepage

    ... or so I misread the headline at first glance.

  • I bet we could shift an asteroid's course if we packed up all the copies of Battlefield Earth and launched them against it.
    /Though I personally think the Mission Earth series was by far the longest series of crap books ever published.

  • by dbIII (701233) on Thursday August 09, 2012 @04:19AM (#40928617)
    How else can you explain the time dilation of the painfully drawn out scene while the timer is ticking down and the audience is screaming "it's been minutes and supposed to be seconds - just die!".
    Either than or about the fiftieth continuity or stupidly ignored fact failure of the movie.
    There were Highlander sequals that made more sense - even the one where the sword changed from claymore to katana and back again in the middle of a fight.
  • No problem. If it's one thing the human race is good at, it's making bigger and better bombs.

  • A 1000 km asteroid is rather enormous; it's estimated that a 10 km asteroid killed off the dinosaurs. That's got a mass of roughly one millionth that of the 1000 KM asteroid.

    Suddenly we go from a billion times more powerful than we've ever detonated, to only one thousand times. That would seem to put it in the realm of feasibility; you build multiple much bigger bombs.

    If we need a thousand times more than Tsar Bomba, that means we need a total of 50,000 megatons. An as-designed Tsar Bomba was twice as power

    • Re:1000 KM? (Score:5, Informative)

      by tp1024 (2409684) on Thursday August 09, 2012 @06:00AM (#40929113)

      Even worse: There are no asteroids with a diameter of 1000km. The largest of them, Ceres, is 950km and at a very safe distance in a very stable orbit. The second largest, Vesta, is less than 600km in diameter.

      In fact, the main "danger" nowadays is seen in objects of about 0.1km in diameter, since that is the size at which asteroids are still damaging, but also escape early detection. That takes about 15 orders of magnitude off the energy requirements. But at this point, you wouldn't even need a bomb. Just shoving a few tons of stuff at a few km/s in front of the asteroid is enough to tear it apart. (The kinetic energy of 1t of material at 2.8km/s is equivalent to 1t of TNT.)

  • by RudyHartmann (1032120) on Thursday August 09, 2012 @05:07AM (#40928841)

    Another big point missed in the movie is that the Space Shuttle is only capable of going to Low Earth Orbit. Bruce Willis wouldn't have even been able to get the bomb there even if it was big enough.

  • I know this is a fault of the movie, not the paper, but there aren't any asteroids 1000 km in diameter (Ceres is just a little bit smaller).

    The only way that the movie could be even remotely plausible would be if this were an extra-solar body coming from interstellar space. Otherwise it would have been detected centuries ago. (Actually, I think the movie indicated something like this). It would also probably be traveling at a high rate of speed since it would have been dropped almost all the way down the

  • Five words (Score:2, Flamebait)

    It's just a fucking movie.

  • If they cannot destroy even a small asteroid?

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