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Thread: A stupid question?

  1. #1 A stupid question? 
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    OK. This is my first post on here. I have a question that's been bothering for some time now.

    Let's assume, for a moment, that it was possible to generate a black hole at a fixed distance from a space craft. The theory is that the black hole would draw the ship forward. Since the black hole is generated from the ship itself, it would remain the same distance away while pulling the ship after it.

    Now I'm no physicist, but I believe that such an arrangement would violate a couple of the laws of physics. Comments?


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    Assumption is wierd to say the least, but we'll ignore that. If there is a black hole at some distance from a space ship, it doesn't matter how it got there as far as its effect on the space ship.


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    Quote Originally Posted by mathman View Post
    Assumption is wierd to say the least, but we'll ignore that. If there is a black hole at some distance from a space ship, it doesn't matter how it got there as far as its effect on the space ship.
    IDK. It seems to me that some law of physics would have to be broken for this to work.
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    Quote Originally Posted by Mr. Plank View Post
    IDK. It seems to me that some law of physics would have to be broken for this to work.
    Correct. I.e. it wouldn't work since part of original premise is that "[S]ince the black hole is generated from the ship itself, it would remain the same distance away".
    So (using actual physics) either:
    A) The ship/ BH distance would decrease, or
    B) There'd be no movement at all.
    Try it with a very strong magnet, a piece of iron and a strong spacer1 between the two - nothing happens.


    1 A strong spacer otherwise the distance does alter, thus violating the premise.
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    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by Mr. Plank View Post
    IDK. It seems to me that some law of physics would have to be broken for this to work.
    Correct. I.e. it wouldn't work since part of original premise is that "[S]ince the black hole is generated from the ship itself, it would remain the same distance away".
    So (using actual physics) either:
    A) The ship/ BH distance would decrease, or
    B) There'd be no movement at all.
    Try it with a very strong magnet, a piece of iron and a strong spacer1 between the two - nothing happens.


    1 A strong spacer otherwise the distance does alter, thus violating the premise.
    Think about this. The BH is projected by the ship, probably using multiple lasers focused on a point in front of the ship. If these lasers stop pumping the energy required to maintain it, it instantly ceases to exist. Now, we have already established that the black hole, however it got there, will draw the ship towards it. When this happens, the BH will move relative to the ship, since the ship is generating it. Think of how massive bodies affect space time. Have you seen the example of the bowling ball on a flexible surface and smaller objects being drawn to it? This is how it should work. Does this make any sense?
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  7. #6  
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    Quote Originally Posted by Mr. Plank View Post
    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by Mr. Plank View Post
    IDK. It seems to me that some law of physics would have to be broken for this to work.
    Correct. I.e. it wouldn't work since part of original premise is that "[S]ince the black hole is generated from the ship itself, it would remain the same distance away".
    So (using actual physics) either:
    A) The ship/ BH distance would decrease, or
    B) There'd be no movement at all.
    Try it with a very strong magnet, a piece of iron and a strong spacer1 between the two - nothing happens.


    1 A strong spacer otherwise the distance does alter, thus violating the premise.
    Think about this. The BH is projected by the ship, probably using multiple lasers focused on a point in front of the ship. If these lasers stop pumping the energy required to maintain it, it instantly ceases to exist. Now, we have already established that the black hole, however it got there, will draw the ship towards it. When this happens, the BH will move relative to the ship, since the ship is generating it. Think of how massive bodies affect space time. Have you seen the example of the bowling ball on a flexible surface and smaller objects being drawn to it? This is how it should work. Does this make any sense?
    There are a lot of problem with this.
    To "create" a black hole with lasers, you would have to have enough energy concentrated at a point to produce enough mass equivalence for the BH to form around, I'm not sure if it is even possible for lasers to do this. And even if it were possible, if you have this much energy available, you could just use it to propel your ship directly.

    Your black hole would have to have sufficient mass to provide you with a measurable acceleration towards it.

    So let's say you want a 1 g acceleration. You can't have the BH too close, because Tidal effects, etc. So let's put it 1 km away. Now if we work out how much mass this black hole would need, it's ~1.47e17 kg. And once you form the BH, it is not going just disappear if you shut off the lasers. It going to last as long as it take to evaporate via Hawking radiation. For a BH of this mass, we are talking billions of years.
    This means that once you form the BH it will want to continue to exist on it own, and you will not need the lasers to "maintain" it. But this also means that it location will no longer be dependent on where the lasers are focused. The lasers form the BH, you start to fall towards, it, the focus point of the laser move past the black hole, the Black hole continues to exist after the lasers move on, and you run into the black hole. The idea that the you will only have a black hole where the lasers are pointing at at any given moment is unfounded.

    Sorry, but this idea is just a non-starter.
    "Men are apt to mistake the strength of their feelings for the strength of their argument.
    The heated mind resents the chill touch & relentless scrutiny of logic"-W.E. Gladstone


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  8. #7  
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    Quote Originally Posted by Janus View Post
    Quote Originally Posted by Mr. Plank View Post
    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by Mr. Plank View Post
    IDK. It seems to me that some law of physics would have to be broken for this to work.
    Correct. I.e. it wouldn't work since part of original premise is that "[S]ince the black hole is generated from the ship itself, it would remain the same distance away".
    So (using actual physics) either:
    A) The ship/ BH distance would decrease, or
    B) There'd be no movement at all.
    Try it with a very strong magnet, a piece of iron and a strong spacer1 between the two - nothing happens.


    1 A strong spacer otherwise the distance does alter, thus violating the premise.
    Think about this. The BH is projected by the ship, probably using multiple lasers focused on a point in front of the ship. If these lasers stop pumping the energy required to maintain it, it instantly ceases to exist. Now, we have already established that the black hole, however it got there, will draw the ship towards it. When this happens, the BH will move relative to the ship, since the ship is generating it. Think of how massive bodies affect space time. Have you seen the example of the bowling ball on a flexible surface and smaller objects being drawn to it? This is how it should work. Does this make any sense?
    There are a lot of problem with this.
    To "create" a black hole with lasers, you would have to have enough energy concentrated at a point to produce enough mass equivalence for the BH to form around, I'm not sure if it is even possible for lasers to do this. And even if it were possible, if you have this much energy available, you could just use it to propel your ship directly.

    Your black hole would have to have sufficient mass to provide you with a measurable acceleration towards it.

    So let's say you want a 1 g acceleration. You can't have the BH too close, because Tidal effects, etc. So let's put it 1 km away. Now if we work out how much mass this black hole would need, it's ~1.47e17 kg. And once you form the BH, it is not going just disappear if you shut off the lasers. It going to last as long as it take to evaporate via Hawking radiation. For a BH of this mass, we are talking billions of years.
    This means that once you form the BH it will want to continue to exist on it own, and you will not need the lasers to "maintain" it. But this also means that it location will no longer be dependent on where the lasers are focused. The lasers form the BH, you start to fall towards, it, the focus point of the laser move past the black hole, the Black hole continues to exist after the lasers move on, and you run into the black hole. The idea that the you will only have a black hole where the lasers are pointing at at any given moment is unfounded.

    Sorry, but this idea is just a non-starter.
    Once again, the question assumes the ability to create a Black Hole, as I have described. Quit harping about it. This question relates to whether such a drive could work, given the assumption that the BH could be created and controlled. Please confine your comments to this. The mechanics of creating the BH are irrelevant to the question. Just ignore them and answer my question. Is there any scientific reason that it would not work as described?
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  9. #8  
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    Quote Originally Posted by Mr. Plank View Post
    Quote Originally Posted by Janus View Post
    Quote Originally Posted by Mr. Plank View Post
    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by Mr. Plank View Post
    IDK. It seems to me that some law of physics would have to be broken for this to work.
    Correct. I.e. it wouldn't work since part of original premise is that "[S]ince the black hole is generated from the ship itself, it would remain the same distance away".
    So (using actual physics) either:
    A) The ship/ BH distance would decrease, or
    B) There'd be no movement at all.
    Try it with a very strong magnet, a piece of iron and a strong spacer1 between the two - nothing happens.


    1 A strong spacer otherwise the distance does alter, thus violating the premise.
    Think about this. The BH is projected by the ship, probably using multiple lasers focused on a point in front of the ship. If these lasers stop pumping the energy required to maintain it, it instantly ceases to exist. Now, we have already established that the black hole, however it got there, will draw the ship towards it. When this happens, the BH will move relative to the ship, since the ship is generating it. Think of how massive bodies affect space time. Have you seen the example of the bowling ball on a flexible surface and smaller objects being drawn to it? This is how it should work. Does this make any sense?
    There are a lot of problem with this.
    To "create" a black hole with lasers, you would have to have enough energy concentrated at a point to produce enough mass equivalence for the BH to form around, I'm not sure if it is even possible for lasers to do this. And even if it were possible, if you have this much energy available, you could just use it to propel your ship directly.

    Your black hole would have to have sufficient mass to provide you with a measurable acceleration towards it.

    So let's say you want a 1 g acceleration. You can't have the BH too close, because Tidal effects, etc. So let's put it 1 km away. Now if we work out how much mass this black hole would need, it's ~1.47e17 kg. And once you form the BH, it is not going just disappear if you shut off the lasers. It going to last as long as it take to evaporate via Hawking radiation. For a BH of this mass, we are talking billions of years.
    This means that once you form the BH it will want to continue to exist on it own, and you will not need the lasers to "maintain" it. But this also means that it location will no longer be dependent on where the lasers are focused. The lasers form the BH, you start to fall towards, it, the focus point of the laser move past the black hole, the Black hole continues to exist after the lasers move on, and you run into the black hole. The idea that the you will only have a black hole where the lasers are pointing at at any given moment is unfounded.

    Sorry, but this idea is just a non-starter.
    Once again, the question assumes the ability to create a Black Hole, as I have described. Quit harping about it. This question relates to whether such a drive could work, given the assumption that the BH could be created and controlled. Please confine your comments to this. The mechanics of creating the BH are irrelevant to the question. Just ignore them and answer my question. Is there any scientific reason that it would not work as described?
    So basically you're asking "If I'm allowed to ignore the laws of physics would it work?" No matter how you create the black hole, it will tend to exist on its own after that, even if the influence that created goes away. Nor will its position relative to the ship remain constant.
    "Men are apt to mistake the strength of their feelings for the strength of their argument.
    The heated mind resents the chill touch & relentless scrutiny of logic"-W.E. Gladstone


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  10. #9  
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    Quote Originally Posted by Janus View Post
    Quote Originally Posted by Mr. Plank View Post
    Quote Originally Posted by Janus View Post
    Quote Originally Posted by Mr. Plank View Post
    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by Mr. Plank View Post
    IDK. It seems to me that some law of physics would have to be broken for this to work.
    Correct. I.e. it wouldn't work since part of original premise is that "[S]ince the black hole is generated from the ship itself, it would remain the same distance away".
    So (using actual physics) either:
    A) The ship/ BH distance would decrease, or
    B) There'd be no movement at all.
    Try it with a very strong magnet, a piece of iron and a strong spacer1 between the two - nothing happens.


    1 A strong spacer otherwise the distance does alter, thus violating the premise.
    Think about this. The BH is projected by the ship, probably using multiple lasers focused on a point in front of the ship. If these lasers stop pumping the energy required to maintain it, it instantly ceases to exist. Now, we have already established that the black hole, however it got there, will draw the ship towards it. When this happens, the BH will move relative to the ship, since the ship is generating it. Think of how massive bodies affect space time. Have you seen the example of the bowling ball on a flexible surface and smaller objects being drawn to it? This is how it should work. Does this make any sense?
    There are a lot of problem with this.
    To "create" a black hole with lasers, you would have to have enough energy concentrated at a point to produce enough mass equivalence for the BH to form around, I'm not sure if it is even possible for lasers to do this. And even if it were possible, if you have this much energy available, you could just use it to propel your ship directly.

    Your black hole would have to have sufficient mass to provide you with a measurable acceleration towards it.

    So let's say you want a 1 g acceleration. You can't have the BH too close, because Tidal effects, etc. So let's put it 1 km away. Now if we work out how much mass this black hole would need, it's ~1.47e17 kg. And once you form the BH, it is not going just disappear if you shut off the lasers. It going to last as long as it take to evaporate via Hawking radiation. For a BH of this mass, we are talking billions of years.
    This means that once you form the BH it will want to continue to exist on it own, and you will not need the lasers to "maintain" it. But this also means that it location will no longer be dependent on where the lasers are focused. The lasers form the BH, you start to fall towards, it, the focus point of the laser move past the black hole, the Black hole continues to exist after the lasers move on, and you run into the black hole. The idea that the you will only have a black hole where the lasers are pointing at at any given moment is unfounded.

    Sorry, but this idea is just a non-starter.
    Once again, the question assumes the ability to create a Black Hole, as I have described. Quit harping about it. This question relates to whether such a drive could work, given the assumption that the BH could be created and controlled. Please confine your comments to this. The mechanics of creating the BH are irrelevant to the question. Just ignore them and answer my question. Is there any scientific reason that it would not work as described?
    So basically you're asking "If I'm allowed to ignore the laws of physics would it work?" No matter how you create the black hole, it will tend to exist on its own after that, even if the influence that created goes away. Nor will its position relative to the ship remain constant.
    You're deflecting again. The question assumes that the black hole can be created and controlled. Forget about the f*cking black hole and answer the question! If this hypothetical space drive could be developed, would it work. Would the black hole draw the ship towards itself while maintaining the same distance from the ship?
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    Quote Originally Posted by Mr. Plank View Post
    Think about this.
    I have.

    Now, we have already established that the black hole, however it got there, will draw the ship towards it. When this happens, the BH will move relative to the ship, since the ship is generating it.
    The problem is that you have specified that the BH remains the same distance away from the ship. Therefore there can - by definition - be no movement.

    Does this make any sense?
    No.

    Is there any scientific reason that it would not work as described?
    Yes - as described.

    Would the black hole draw the ship towards itself while maintaining the same distance from the ship?
    No. The premise is similar to pulling yourself off the ground by tugging on your own bootstraps.
    Given that - as per your spec - the BH remains at a fixed distance from the ship then there is no movement whatsoever. Whatever is used to maintain the ship/ BH separation prevents the ship moving toward the BH.
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    Fictionally, anything is possible, so yes it is possible, because you get to ignore anything you dont like. As soon as you ask about the physics, you'll get the problems described above that seem to be irritating you.
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    Quote Originally Posted by Mr. Plank View Post
    You're deflecting again.

    And you're not taking any notice of replies.

    [
    quote]Forget about the f*cking black hole and answer the question![/quote]
    The question HAS been answered. If you wish to ignore it that's fine, but berating members who have put in the time to reply doesn't help your case.
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  14. #13  
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    So, returning to the title of the thread, the answer appears to be "Yes".
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    Quote Originally Posted by Mr. Plank View Post


    You're deflecting again. The question assumes that the black hole can be created and controlled. Forget about the f*cking black hole and answer the question! If this hypothetical space drive could be developed, would it work. Would the black hole draw the ship towards itself while maintaining the same distance from the ship?
    So are you imagining the BH as a tow truck of some sorts - The ship creates a BH at a given distance in front of it, that BH then tethers the ship by gravity and draws the ship towards it?

    I can't see how it would work?? The ship would have to remain in a position where it would never get closer to the BH and the BH would have to be accelerating away from the ship, i.e the tow truck analogy. How do you get the BH to accelerate away from the ship?
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    Quote Originally Posted by David M W View Post
    Quote Originally Posted by Mr. Plank View Post


    You're deflecting again. The question assumes that the black hole can be created and controlled. Forget about the f*cking black hole and answer the question! If this hypothetical space drive could be developed, would it work. Would the black hole draw the ship towards itself while maintaining the same distance from the ship?
    So are you imagining the BH as a tow truck of some sorts - The ship creates a BH at a given distance in front of it, that BH then tethers the ship by gravity and draws the ship towards it?

    I can't see how it would work?? The ship would have to remain in a position where it would never get closer to the BH and the BH would have to be accelerating away from the ship, i.e the tow truck analogy. How do you get the BH to accelerate away from the ship?
    Once the BH is created, it will draw the ship towards it. Simple physics here. Since the ship is projecting the black hole, it moves with the ship. You know what? Perhaps using a black hole is a mistake. How about an artificially generated gravity well, or a gravity gradient? Either way, gravity will draw the ship towards it. As it does so, it will move with the ship because it is being generated by the ship.
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    Lets break this down into a very simple analogy. Pulling something over round rods on a flat surface.

    No matter what you do, youll be expending more energu, being fiction you can ignore anything you find inconvenient but of you ask about the known physics ill just point out its easier to use "thrusters" "hyperactive" "warp drive" or similar fiction pushing engines
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    Quote Originally Posted by Mr. Plank View Post
    Once the BH is created, it will draw the ship towards it. Simple physics here.
    Unless something stops it - equally simple physics.

    Since the ship is projecting the black hole, it moves with the ship.
    But your premise is that the BH remains at fixed distance from the ship. Ergo No movement.

    Either way, gravity will draw the ship towards it. As it does so, it will move with the ship because it is being generated by the ship.
    No.
    Try this: the world's most powerful motor pulling (via an unbreakable cable) a small box. But the cable runs through an uncrushable tube of fixed length that's in contact with the motor at one end and the box at the other: no movement.

    Mod note: Unless you come up with a better argument for your position than you have presented so far (i.e. try to address the multiple posts that explain why you're wrong without simply repeating the same tired and incorrect, claims) then don't bother replying.
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    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by Mr. Plank View Post
    Once the BH is created, it will draw the ship towards it. Simple physics here.
    Unless something stops it - equally simple physics.

    Since the ship is projecting the black hole, it moves with the ship.
    But your premise is that the BH remains at fixed distance from the ship. Ergo No movement.

    Either way, gravity will draw the ship towards it. As it does so, it will move with the ship because it is being generated by the ship.
    No.
    Try this: the world's most powerful motor pulling (via an unbreakable cable) a small box. But the cable runs through an uncrushable tube of fixed length that's in contact with the motor at one end and the box at the other: no movement.

    Mod note: Unless you come up with a better argument for your position than you have presented so far (i.e. try to address the multiple posts that explain why you're wrong without simply repeating the same tired and incorrect, claims) then don't bother replying.
    No one has submitted any scientific evidence that I am wrong. They have offered opinions. And why are my claims incorrect? Because YOU say so? I don't care if you're a MOD. My opinion is just as valid as anyone else's opinion. Seems like you're taking sides. I thought MODS were supposed to be impartial.
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    Quote Originally Posted by Mr. Plank View Post
    No one has submitted any scientific evidence that I am wrong.
    Then - obviously - you haven't read a single one of those replies.

    They have offered opinions.
    No, you haven't been offered opinions you've been given facts.

    And why are my claims incorrect?
    Because - as has been stated more than once - you specified that the BH is at a fixed distance from the ship. That means that the ship CANNOT move toward the BH.

    Because YOU say so?
    Because it's basic physics.

    My opinion is just as valid as anyone else's opinion.
    Unfortunately science isn't a matter of opinion - and you're the only one giving an opinion. The rest of us are using science.

    Seems like you're taking sides. I thought MODS were supposed to be impartial.
    I'm on the side of science (this is a science forum).

    Refute my example with the motor and tube: then we might take some notice.
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    Quote Originally Posted by Mr. Plank View Post
    No one has submitted any scientific evidence that I am wrong. They have offered opinions.
    They have given you answers based on the laws of Physics, not "opinions". Basically, what they are saying is that what you propose would violate certain laws of Physics (conservation of momentum, for one)
    And why are my claims incorrect? Because YOU say so? I don't care if you're a MOD. My opinion is just as valid as anyone else's opinion.
    No, it isn't. Not on a subject on which others are better versed. My doctor's opinion on medical issues is more valid than my tax preparer's, but my tax preparer's opinion on taxes is more valid than my Doctor's. The idea that everyone's opinion is equally valid on all subjects is just ridiculous.
    Seems like you're taking sides. I thought MODS were supposed to be impartial.
    That impartiality only pertains to enforcing the rules of the Forum, not to taking positions on the subject of posts. If someone were to start hurling personal insults around, it would be the moderator's job to step in an take the appropriate action, regardless of wheter or not the moderator agreed with that person's position on the issue at hand or not. A moderator can also step in if he feels one side is not debating in good faith.

    Moderators are perfectly free to have and post their own positions.
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    Quote Originally Posted by Janus View Post
    Quote Originally Posted by Mr. Plank View Post
    No one has submitted any scientific evidence that I am wrong. They have offered opinions.
    They have given you answers based on the laws of Physics, not "opinions". Basically, what they are saying is that what you propose would violate certain laws of Physics (conservation of momentum, for one)
    And why are my claims incorrect? Because YOU say so? I don't care if you're a MOD. My opinion is just as valid as anyone else's opinion.
    No, it isn't. Not on a subject on which others are better versed. My doctor's opinion on medical issues is more valid than my tax preparer's, but my tax preparer's opinion on taxes is more valid than my Doctor's. The idea that everyone's opinion is equally valid on all subjects is just ridiculous.
    Seems like you're taking sides. I thought MODS were supposed to be impartial.
    That impartiality only pertains to enforcing the rules of the Forum, not to taking positions on the subject of posts. If someone were to start hurling personal insults around, it would be the moderator's job to step in an take the appropriate action, regardless of wheter or not the moderator agreed with that person's position on the issue at hand or not. A moderator can also step in if he feels one side is not debating in good faith.

    Moderators are perfectly free to have and post their own positions.
    What you are all missing here is that this discussion is about something that is theoretical and doesn't even exist. So how can anyone's opinion be scientific? Some of you even refused to answer the question and started harping about how a controlled black hole is impossible. The simple FACT is that if it was possible to generate an artificial black hole, it's gravity well would draw the ship towards itself. That's simple physics. Now, it is possible that the black hole will move with the ship since the ship is feeding it the power it needs to sustain itself. If the ship moves, the black hole will move with it because it is being generated at a fixed distance from the ship. Also, as I mentioned earlier, this is not your typical black hole. It is an artificial construct that requires a constant flow of energy to exist. So when it draws the ship towards itself, the point of focus for the energy it receives changes, however slightly.
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  23. #22  
    Forum Radioactive Isotope Paleoichneum's Avatar
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    What exactly do you want from the forum then? As soon as we point out scientific problems with your idea, you get annoyed and say that we should ignore the science. There is NO way to respond to you other then patting you on the back and saying good job it seems
    If more of us valued food and cheer and song above hoarded gold, it would be a merrier world. -Thorin Oakenshield

    The needs of the many outweigh the need of the few - Spock of Vulcan & Sentinel Prime of Cybertron ---proof that "the needs" are in the eye of the beholder.
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  24. #23  
    Genius Duck Moderator Dywyddyr's Avatar
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    Quote Originally Posted by Mr. Plank View Post
    What you are all missing here is that this discussion is about something that is theoretical and doesn't even exist. So how can anyone's opinion be scientific?
    And what you are missing is that the principle is scientific.

    Some of you even refused to answer the question and started harping about how a controlled black hole is impossible.
    And those that didn't get sidetracked...?

    The simple FACT is that if it was possible to generate an artificial black hole, it's gravity well would draw the ship towards itself. That's simple physics.
    Correct.
    IF there wasn't the proviso that you gave that the BH remains at a fixed distance from the ship. In such a case the ship will not - can not - move.

    Now, it is possible that the black hole will move with the ship
    No. It is not possible.
    How many more times do you need to be told?

    If the ship moves, the black hole will move with it because it is being generated at a fixed distance from the ship.
    Given that the distance is fixed then ship will not move. For the umpteenth time.

    Also, as I mentioned earlier, this is not your typical black hole. It is an artificial construct that requires a constant flow of energy to exist.
    It doesn't matter how the BH got there.

    So when it draws the ship towards itself, the point of focus for the energy it receives changes, however slightly.
    FIXED DISTANCE - therefore no ship movement.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
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  25. #24  
    Genius Duck Moderator Dywyddyr's Avatar
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    Quote Originally Posted by Paleoichneum View Post
    What exactly do you want from the forum then? As soon as we point out scientific problems with your idea, you get annoyed and say that we should ignore the science. There is NO way to respond to you other then patting you on the back and saying good job it seems
    Funnily enough this was today's Dilbert strip:


    Dunning-Kruger strikes again...
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
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  26. #25  
    exchemist
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    Quote Originally Posted by Mr. Plank View Post
    Quote Originally Posted by Janus View Post
    Quote Originally Posted by Mr. Plank View Post
    No one has submitted any scientific evidence that I am wrong. They have offered opinions.
    They have given you answers based on the laws of Physics, not "opinions". Basically, what they are saying is that what you propose would violate certain laws of Physics (conservation of momentum, for one)
    And why are my claims incorrect? Because YOU say so? I don't care if you're a MOD. My opinion is just as valid as anyone else's opinion.
    No, it isn't. Not on a subject on which others are better versed. My doctor's opinion on medical issues is more valid than my tax preparer's, but my tax preparer's opinion on taxes is more valid than my Doctor's. The idea that everyone's opinion is equally valid on all subjects is just ridiculous.
    Seems like you're taking sides. I thought MODS were supposed to be impartial.
    That impartiality only pertains to enforcing the rules of the Forum, not to taking positions on the subject of posts. If someone were to start hurling personal insults around, it would be the moderator's job to step in an take the appropriate action, regardless of wheter or not the moderator agreed with that person's position on the issue at hand or not. A moderator can also step in if he feels one side is not debating in good faith.

    Moderators are perfectly free to have and post their own positions.
    What you are all missing here is that this discussion is about something that is theoretical and doesn't even exist. So how can anyone's opinion be scientific? Some of you even refused to answer the question and started harping about how a controlled black hole is impossible. The simple FACT is that if it was possible to generate an artificial black hole, it's gravity well would draw the ship towards itself. That's simple physics. Now, it is possible that the black hole will move with the ship since the ship is feeding it the power it needs to sustain itself. If the ship moves, the black hole will move with it because it is being generated at a fixed distance from the ship. Also, as I mentioned earlier, this is not your typical black hole. It is an artificial construct that requires a constant flow of energy to exist. So when it draws the ship towards itself, the point of focus for the energy it receives changes, however slightly.
    Nope. Energy considerations show this to be unworkable. As an object moves towards a source of gravitation it does so because it thereby moves to a lower potential energy state, losing gravitational potential energy in exchange for the mechanical work (Fd) done on the object. If your ship keeps the distance from the attractor fixed, no reduction in potential energy can occur, so no work is done by gravitation and no motion will result. You can't have it both ways, just as everyone has been pointing out.

    But the whole thing is silly anyway, since you ask first for the laws of physics to be suspended to create this imaginary black hole and then demand that we apply physics to the resulting problem - but not if we get a different answer from the one you want! It beats me why you ask the question if you cannot deal with the answer.
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  27. #26  
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    Quote Originally Posted by Mr. Plank View Post
    [
    What you are all missing here is that this discussion is about something that is theoretical and doesn't even exist. So how can anyone's opinion be scientific? Some of you even refused to answer the question and started harping about how a controlled black hole is impossible. The simple FACT is that if it was possible to generate an artificial black hole, it's gravity well would draw the ship towards itself. That's simple physics. Now, it is possible that the black hole will move with the ship since the ship is feeding it the power it needs to sustain itself. If the ship moves, the black hole will move with it because it is being generated at a fixed distance from the ship. Also, as I mentioned earlier, this is not your typical black hole. It is an artificial construct that requires a constant flow of energy to exist. So when it draws the ship towards itself, the point of focus for the energy it receives changes, however slightly.
    What you keep missing is that "theoretical" here means "made-up fantasy". You may have in your head precisely in what ways you are suspending the laws of physics, but you have done a poor job of conveying those to us.

    In general, these types of questions are, ultimately, sort of pointless. Once you decide to invoke magic in some way, it's silly to say that you will not allow magic elsewhere in the problem. Your frustration -- and unwarranted rudeness -- derives from an ill-founded belief that there is a definite answer to a vaguely formed question. Without the constraints of reality to enforce a set of rules of engagement, there is no way to provide a meaningful answer to what is actually a meaningless question. It's exactly as if you said "Imagine Santa Claus exists," then we reply with "Then reindeer would spontaneously catch fire," only to have you retort "That's silly; the reindeer are obviously made of asbestos." See what I mean? Once you suspend the rules of physics, anything goes.
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  28. #27  
    exchemist
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    The above made me burst out laughing.
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  29. #28  
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    Quote Originally Posted by Mr. Plank View Post
    Once again, the question assumes the ability to create a Black Hole, as I have described. Quit harping about it. This question relates to whether such a drive could work, given the assumption that the BH could be created and controlled. Please confine your comments to this. The mechanics of creating the BH are irrelevant to the question. Just ignore them and answer my question. Is there any scientific reason that it would not work as described?
    OK. It would not work because the black hole would not move away from the ship as the ship fell towards it.
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  30. #29  
    Moderator Moderator Markus Hanke's Avatar
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    The theory is that the black hole would draw the ship forward
    Yes, the ship will fall into the black hole. The physics of this situation are the same ones as for a hole-ship system that is at rest with respect to a distant reference point.

    Since the black hole is generated from the ship itself, it would remain the same distance away while pulling the ship after it.
    No. Both ship and black hole will be in motion with respect to a distant reference point, but the distance between ship and black hole will gradually reduce also. To put it more succinctly, the hole-ship system will be in motion, while at the same time the ship will fall into the black hole. After a finite proper time, the ship will have fallen through the event horizon, and only the black hole remains - still in motion wrt to an external reference point.

    The reason for this is that spacetime in the vicinity of the black hole is not flat, so there will be non-vanishing geodesic deviation. If you want to keep the distance between black hole and ship constant, you will have to fire your thrusters to provide radially-outwards pointing acceleration. This means you have to exert energy. Together with the huge amount of energy needed to create the black hole in the first place (I donít think as a non-physicist you have any comprehension just how much energy that would really take), this renders the whole scenario completely useless. From an energy perspective, you are much better off just powering your ship by standard propulsion methods.

    The other problem of course is that once in motion, there is no way for you to change your direction of travel, or bring the hole-ship system to a halt. A very awkward caveat.

    Now I'm no physicist, but I believe that such an arrangement would violate a couple of the laws of physics
    Not really, but for the reasons listed above it would provide no practical advantages either. More like the opposite. All of the same points also apply to more general gravitational gradients.
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  31. #30  
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    Way back in post 4, Dywyddyr showed how the OP can prove to himself in his own living room that it won't work.

    Take a toy metal spaceship, attach a rigid rod to its tip. At the end of the rod, attach a magnet.

    The magnet is placed and held in position by the spaceship. The spaceship is attracted to the magnet.

    Yet, the spaceship/rod/magnet contraption goes nowhere.

    Perfectly analogous, perfectly scientific, perfectly simple, and perfectly irrefutable.

    In fact, it's so compelling that I predict the OP will simply ignore it.
    This space for rent
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