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Destroying An Asteroid.

  1. Aug 21, 2006 #1
    They say if we needed to destroy and asteroid headed for Earth the fastest easiest way is witha nuclear bomb. If we used it it would destroy it but it would create thousands of pieces falling to Earth which would be much worse.

    In a special it was said that it would take a bomb on the order of 1,000 megatons to completly destroy an asteroid. It would not only be the biggest bomb ever built but it would need to be put on the biggest rocket ever built. My soloution could be simple. INstead of building one big bomb build about 10 smaller ones. launch 10 smaller nuclear warheads and attach them all to the asteroid. THen at the precise moment they all go off.

    SInce there would be 10 each one would be around 100 megatons. And since it not one concentrated into one place they would have a better chance of destroying all the asteroid. I think 100 megatons is well within our bombmaking capabilitites. If we make them light enough we could put 2 on each rocket only requiring 5 launches. This sounds easy and simple. Why hasn't anybody ever thought of this?
     
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  3. Aug 21, 2006 #2

    DaveC426913

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    They have. Because it isn't.

    There is a wealth of info to read on the shortcomings of any variation of the concept of blowing up an asteroid with a missile.
     
  4. Aug 21, 2006 #3

    Astronuc

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    How does one know that some have not already addressed this matter?

    Those who would contemplate such technology do not talk about it openly. :cool:

    It is more likely that one would divert an asteroid rather than blowing it up. Blowing it up would put a lot of debris near earth, and debris in orbit is something to be avoided. It has the potential to lots of damage to satellites, spacecraft, and space stations. :rolleyes:
     
    Last edited: Aug 21, 2006
  5. Aug 22, 2006 #4

    Yaaay let's blow up an asteroid, that can destroy us,mankind,our history,and all our fututre. But wait, the debris will hit our sattelites..........damn. Oh well.


    And the moral is, sattelites are mroe important than mankinds survival.
     
  6. Aug 22, 2006 #5

    Astronuc

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    No quite. Find a way to deflect the asteroid so that it misses earth and avoid damage to satellites, which provide for monitoring of weather and for communication. Perhaps the asteroid could be blown up after is passes earth.
     
  7. Aug 22, 2006 #6
    If it's going to pass Eartht here's no need to worry.

    Anyhow, it would take some state of the art stuff to deflect it. Unless of course you want to use nuclear weapons. That of course would be if we have time. If we find an asteroid tommorow and finfout it's goign to collide with Earth 2 weeks from now there'd be little we could do but destroy it.

    Deflectin take lots of time,planning, and cordination. My favorite is we attach huge rockets to it, slow it down, and mine the thing for minerals.
    There's enough raw material in the average asteroid to wipe out the national debt.
     
  8. Aug 22, 2006 #7

    LURCH

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    Setting aside the risk to the satellites and space stations, etc., deflecting an incoming threat is far more desirable than blowing it to bits. A single impact at a single location on earth's surface would be devastating, and if you would survive, but breaking the abject into thousands of impacts over the entire surface would ensure that no one survives. But it just so happens that nuclear weapons are the best tools for deflecting a potential impactor.

    I think this is another excellent reason why we need a lunar launch facility. Storing thousands of nuclear weapons mounted on launch vehicles on earth has always been a bad thing; it's inherently dangerous. The same weapons sitting on the surface of the moon (or in orbit around the moon) pose no threat to those of us here on Earth. If the orbit decays, or there is an accidental launch or detonation, the event will go virtually unnoticed. If someone launches a weapon "in anger", there will be almost a week during which to intercept it.

    A lunar launch facility for nukes also puts them in a position to be launched with greater velocity, and therefore intercept the object sooner.
     
  9. Aug 22, 2006 #8

    DaveC426913

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    :eek: :eek: Are you completely ignoring the lessons learned from Space: 1999?:biggrin:
     
  10. Aug 22, 2006 #9
    I thought that scientists and astronomers had a pretty good idea of anything threatening that was headed toward earth?
     
  11. Aug 22, 2006 #10

    DaveC426913

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    No way. It is well-known that this is impossible with today's technology and manpower.
     
  12. Aug 22, 2006 #11
    Once again ou can destroy an asteroid with nuclear power. YOu could breakit up into piece with a nuclear bomb. Or you can completley destroy it with a 1,000 megaton bomb.
     
  13. Aug 22, 2006 #12

    DaveC426913

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    No. You can't.

    - we don't have the sky watch system to see it in time
    - we don't have the rocket power to get the payload there at all, let alone in any decent time frame
    - we don't have guidance systems that could put it in the right place at the right time (it will be moving quite fast)
    - nuclear bombs simply will NOT destroy an asteroid
    ..- we have no way of controlling what the detonation(s) do in terms of destruction, best we can hope for is to crack it into a few very large pieces, all of which are now on a collision course with Earth
    ..- even the most ambitious collection of nuclear warheads simply does not vapourize of cubic kilometers of solid rock

    (A moderate asteroid is between a thousand and a million Gigatons. Does that put it in perspective?)

    I mean, the idea sounds good at first blush, but when you get down to brass tacks, it simply doesn't work on many, many levels.
     
    Last edited: Aug 22, 2006
  14. Aug 22, 2006 #13
    We can send bombs, if we do smaller ones. If we can fit space telescopes on rockets and send probes to Neptune I'm sure we can get a bomb to just outside Earth orbit.

    Guidance should be no problem since we've landed things on asteroids and flown into comets. Once again it would take 1,000 megatons to completly destroy it. If ou think destroying it takes time guess how long deflecting it takes.

    And I don't see how a bomb could deflect it. Nukes just let off lots nergy like heat.If heat just travels to the asteroid it should just melt it. The reason nukes blow things up on Earth is because the air expands, moves and knocks things down. IN space there is no air and hence nothing can be blown off course.
     
  15. Aug 22, 2006 #14

    DaveC426913

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    Some of this stuff is pretty basic physics.

    There's timing logistics. If we were to blow it up near Earth, we'd be pelted with an asteroid's worth of debris, causing even more damage than a single rock.

    Do you know how long those trips take? Years. Decades.


    Well, we haven't landed on asteroids, no. We've flown one spaceship into one comet, yes.

    I reeally don't know why you keep repeating this, like it's some sort of mantra. Other than a wild guess, do you have any evidence to support this claim?

    Yes, kind of a lot like a rocket engine. You do know that rockets work in space without benefit of air, right?
     
  16. Aug 23, 2006 #15
    Deflecting it would take more time and there was a special on TV about doomsday. It has been calculated that about 1,000 Megs is needed.

    ANd yes rockets need no wind to work. And we have ladned on an asteroid. It wasn't all hi-tech withl legs but I probe was landed on an asteroid.
     
    Last edited: Aug 23, 2006
  17. Aug 23, 2006 #16

    LURCH

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    Yes, the NEAR probe landed on Eros.
    http://liftoff.msfc.nasa.gov/news/2001/news-NEAR.asp

    Unfortunately, early detection is still a very large problem. Not too many years ago, a rather large asteroid (the kind that could do damage on a global scale) was detected after it had made a close pass by the earth. I remember hearing that earth had occupied that exact spot only six hours earlier. IIRC, the highly elliptical orbit of the object brought it very near to the sun, and it passed the earth on its way back out to space. This caused it to come at us "out of the sun", like that tactic used by fighter pilots, with its dark side towards us. As a result, we did not see the object until after it had passed, and sunlight was seen reflecting off its rear as if to say, " bite my shiny metal...".

    This object is thought to be about a half-mile in diameter, and would have released an energy of about 2000 megatons, leaving a crater anywhere from 5 to 10 miles in diameter. The first warning anyone on earth would have had would be the sprouting of a huge mushroom cloud.

    I'm wondering if nukes could be used in a combination of "breaking up" the object and deflection?
     
  18. Aug 23, 2006 #17

    DaveC426913

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    These two methods are mutually exclusive and counterproductive. If you break it up, you now have a zillion unpredictable pieces to deflect. If you're going to deflect it, you want it to be in one piece.
     
  19. Aug 23, 2006 #18

    LURCH

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    That's what I used to think, but now I begin to question whether that is necessarily true. I have been thinking of a strategy in which several missiles are sent to intercept an object at various points along its collision trajectory. This could add redundancy to the system in case one or more missiles failed to guide, or to detonate. Sadly, early detection would still be the key. And early detection is exactly where we are weak.

    The idea occurred to me when I was thinking about the fact that, in order to be on a collision course with Earth, an object must follow a very precise path through both space and time. Disrupting such an object with a large explosion would cause it to break into hundreds, or possibly thousands of pieces. But, by the very nature of the event, these pieces are no longer on the same path. Neither are they on parallel paths. The fact that they are moving away from one another means that they cannot all be headed toward the same destination. So, if a particular fragment is still on a collision course with Earth, then any other fragment moving away from that fragment cannot be on that same collision course. In fact, only a very small number of those fragments could still be on a collision course, and these will all be in fairly close proximity to one another. This small group of fragments will be on or clustered around the original path of the original object (the "collision trajectory").

    Objects on that trajectory will be present at the detonation of several subsequent nuclear devices. The ionizing radiation that makes a nuke useful for deflecting one large object will work even better on several smaller objects. These subsequent detonations will hollow out a "hole" in the debris field, centered around the "collision trajectory". It is this hollow area that will collide with Earth. The remaining fragments in the debris field will be on new trajectory so deviant from the original that they should no longer pose a threat.
     
  20. Aug 23, 2006 #19

    DaveC426913

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    I see a few problems with your approach:

    "...intercept an object at various points along its collision trajectory..."

    How is this better than "all at once?" I grant that redundancy is a good thing, but spreading the impacts out over time gains nothing while costing a certain amount of predictability.


    "...these pieces are no longer on the same path. Neither are they on parallel paths..."

    The relative speed of expanding objects compared to the relative speed of the approach to Earth would make them effectively parallel. The question becomes "If we blow off large chunks, how much speed - if any - did we impart upon these small chunks to deflect them from Earth?"

    Also, don't forget that, as individual free-floating bodies, these large chunks are now free to be pulled toward Earth on their own individual courses as they near. Just because they were given a shove doesn't mean they won't still converge on the Earth.
     
  21. Aug 24, 2006 #20

    LURCH

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    Yeah, that's what I was sayin' about the importance of early detection. The original idea - sending a device to detonate outside the threat object and counting on radiation pressure to give a tiny nudge - was always dependant on getting to the object early enough so that such a tiny nudge would be sufficient.

    The two advantages I think we could gain are:

    1) that the initial blast would be contained inside an enclosed space, so far more of the device's energy would be imparted to the change of course for the resulting fragments. Whatever acceleration this imparts to the fragments would be much greater than that which would be imparted to the whole object by a nearby, exterior blast.

    2) The majority of the object's mass having been deflected, the use of radiation pressure to alter the course of those fragments which still pose a threat would be far more effective, because it would be using the same amount of energy to move a far smaller mass.

    Each blast will accelerate these small fragments a little more, with those pieces that are closest to the collision trajectory getting the most acceleration. This will create an ever-expanding hole at or near the center of the debris field. This hole will continue to expand at whatever speed was imparted to the fragments by the final blast. If all of this takes place many years before the proposed collision date, then by the time that date arrives, no fragment will be anywhere near the Earth.

    At least, that's the theory.
     
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