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Thread: Why FTL Travel Is Impossible In A Way...

  1. #1 Why FTL Travel Is Impossible In A Way... 
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    Alcubierre drive seems to be mankind's only hope for a workable warp drive. Accelerating through space and reaching speeds that go beyond light speed are impossible for a number of reasons, as far as scientists can tell.

    1. Power required to even get anything with mass to light speed is infinite.

    2. Causality. Scientists say that if you go faster than light you will travel backward in time, since nothing from mankinds point of reference flies faster than light in the universe anyway. So for a ballpark figure, let's say for every 60 seconds of FTL travel you go 60 years into the past. Sure you would get around, but you wouldn't be going to the universe you know, you would traveling further and further into the past. No fun.

    Alcubierre drive has it's own issues, but right now, it's the only thing close to a theory that enables scientists to figure a way to fly FTL with traveling through time or requiring overwhelming amounts of energy to power it.

    I have done the research on this online.

    Unless of course we figure out some way to teleport stuff instantly across the galaxy. Assuming the power to do so wasn't infinite and you didn't travel back in time.


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  3. #2  
    Life-Size Nanoputian Flick Montana's Avatar
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    Quote Originally Posted by lorbo View Post
    Alcubierre drive seems to be mankind's only hope for a workable warp drive.
    Why do you say that? Some scientists would argue there are still serious issues with his ideas.


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    Theres other ways for FTL, wormholes for example.

    or, not necessary to actually reach FTL, you could go just below light speed. While the trip would take longer you would age less and the trip would feel shorter from the traveler's perspective.
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  5. #4  
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    Quote Originally Posted by lorbo View Post
    Alcubierre drive seems to be mankind's only hope for a workable warp drive.
    Except that it won't work.

    I have done the research on this online.
    Yeah right, considering that even the Wiki page section on the problems with Alcubierre is as large as the main article and you still claim "it's our only hope".

    PS: Mods this is neither Astronomy nor Cosmology, it's more of Lorbo's non-scientific science fiction crap.
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  6. #5  
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    Quote Originally Posted by lorbo View Post
    Alcubierre drive seems to be mankind's only hope for a workable warp drive. Accelerating through space and reaching speeds that go beyond light speed are impossible for a number of reasons, as far as scientists can tell.

    1. Power required to even get anything with mass to light speed is infinite.

    2. Causality. Scientists say that if you go faster than light you will travel backward in time, since nothing from mankinds point of reference flies faster than light in the universe anyway.
    What scientists are those? All the scientists I know say we cannot go faster than light, not what happens if you go faster than light. Yes, they will concede that in the future, we might learn new physics that will allow "faster than light" but not knowing what that "new physics" will be they certainly cannot say what might happen then.

    So for a ballpark figure, let's say for every 60 seconds of FTL travel you go 60 years into the past. Sure you would get around, but you wouldn't be going to the universe you know, you would traveling further and further into the past. No fun.

    Alcubierre drive has it's own issues, but right now, it's the only thing close to a theory that enables scientists to figure a way to fly FTL with traveling through time or requiring overwhelming amounts of energy to power it.

    I have done the research on this online.

    Unless of course we figure out some way to teleport stuff instantly across the galaxy. Assuming the power to do so wasn't infinite and you didn't travel back in time.
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    i dont see ftl ever being a possiblity but hey i could be wrong.
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    Quote Originally Posted by GoldenRatio View Post
    i dont see ftl ever being a possiblity but hey i could be wrong.
    the problem isn't with finding a method of acceleration that provides FTL, but with providing an object with momentum given it by the environment of it's source materials a means to smoothly disengage with that field momentum and then navigate that mass to a point in which you wish to integrate it's internal momentum with that of the environment again.........(IMO)
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  9. #8  
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    Quote Originally Posted by GoldenRatio View Post
    I don't see FTL ever being a possibility but hey i could be wrong.
    Lets hope you are, or getting off this planet and colonizing new worlds will be very problematic.
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    If only there was a way to move past space instead of moving through it. Like walking in between the raindrops, but the raindrops are space.

    A sort of super-space, if you will.
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  11. #10  
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    Quote Originally Posted by Daecon View Post
    If only there was a way to move past space instead of moving through it. Like walking in between the raindrops, but the raindrops are space.

    A sort of super-space, if you will.
    How is that different from sub-space as used in the Stargate TV program?
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  12. #11  
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    Quote Originally Posted by Bad Robot View Post
    Quote Originally Posted by Daecon View Post
    A sort of super-space, if you will.
    How is that different from sub-space as used in the Stargate TV program?
    It isn't. That's the joke*. I also would have accepted "Star Trek".

    (*Sense of humour may vary.)
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  13. #12  
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    I don't get why people are so obsessed with the speed of light as a speed limit. Its not like any realistic technology can accelerate a passenger to any large fraction of C. The real limits of space travel are in energy storage and drive efficiency, not relativity.
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    Quote Originally Posted by Daecon View Post
    If only there was a way to move past space instead of moving through it. Like walking in between the raindrops, but the raindrops are space.

    A sort of super-space, if you will.
    if only indeed!
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    Quote Originally Posted by danhanegan View Post
    I don't get why people are so obsessed with the speed of light as a speed limit. Its not like any realistic technology can accelerate a passenger to any large fraction of C. The real limits of space travel are in energy storage and drive efficiency, not relativity.
    True.

    In fact, the light speed limit, and the relativistic effects it brings, can actually be a benefit.

    For example: Assuming that we are only concerned with the time passing on the ship, let's compare what it would take to get out ship up to a speed so that it crosses 1 light yr in 2 yrs, given that we have a rocket capable of producing an exhaust velocity of 0.25c, using both Newtonian and Relativistic physics.

    If we ignore Relativity, our ship has to achieve 2c and we get a mass ratio of e^8 or ~2981 using the classical rocket equation.

    With Relativity, we only have to get the ship up to 0.882c in order for time dilation/ length contraction to allow the same trip to be made in 1 yr ship time. If we then apply the relativistic rocket equation to this problem, we get a mass ratio of e^5.54 or ~254, less than 1/10 that needed when we ignored Relativity.
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    "adds 'Janus' to list of lecturers to follow around"-*scribble, scribble, scribble*
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  17. #16  
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    now to find the material that won't break at this speed before thinking on.
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  18. #17  
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    I would be content with 2 way communication with alien civilizations. Tho we need to invest more in METI.

    This passive listening is like never giving anyone your phone number, but yet still hoping they call. I personally dont want to talk to interstellar telemarketers anymore than i want to talk to earth bound ones.
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    Even if we could go as fast as the speed of light (let alone faster) we couldn't ride on that ship could we? accelerating at that speed would likely keep us so pinned down under the force of the travel that our lungs wouldn't work. Don't the astronauts breaking free of the earths gravity have a certain amount of time that the force is so great they can't breathe? I would venture to say that light speed is a little stronger force than breaking free of earth's gravity. so, no breathing...?
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  20. #19  
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    Quote Originally Posted by grmpysmrf View Post
    Even if we could go as fast as the speed of light (let alone faster) we couldn't ride on that ship could we? accelerating at that speed would likely keep us so pinned down under the force of the travel that our lungs wouldn't work. Don't the astronauts breaking free of the earths gravity have a certain amount of time that the force is so great they can't breathe? I would venture to say that light speed is a little stronger force than breaking free of earth's gravity. so, no breathing...?
    You would solve that problem by taking a long time to accelerate up to the speed of light. If you were able to get to the speed of light as long as you are not accelerating you won't feel any G force on your body.
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    Quote Originally Posted by grmpysmrf View Post
    Even if we could go as fast as the speed of light (let alone faster) we couldn't ride on that ship could we? accelerating at that speed would likely keep us so pinned down under the force of the travel that our lungs wouldn't work. Don't the astronauts breaking free of the earths gravity have a certain amount of time that the force is so great they can't breathe? I would venture to say that light speed is a little stronger force than breaking free of earth's gravity. so, no breathing...?
    Within the context of the Alcubierre drive as brought up by the OP, the ship would be locally at rest, so the astronauts would not feel any forces acting on them.
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    not ADM!N grmpysmrf's Avatar
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    Ok good to know.

    so it's kind of like boiling frogs... as long as the temp is upped gradually they'll never know.
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  23. #22  
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    Quote Originally Posted by grmpysmrf View Post
    Ok good to know.

    so it's kind of like boiling frogs... as long as the temp is upped gradually they'll never know.
    If you were to accelerate at 1G, you would be very comfortable getting up to speed, but supposedly you would never get up to the speed of light and it would take a very long time getting close to it. But so what, even at the speed of light it would still be to slow getting anywhere in the galaxy and just forget going to any other galaxy. As Markus said a warp drive is the way to go. But we don't have one yet and maybe never will.
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    Quote Originally Posted by Bad Robot View Post
    But we don't have one yet and maybe never will.
    I personally doubt very much that the Alcubierre drive is physically feasible ( as opposed to being mathematically possible ). I think we should better keep looking for other alternatives.
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  25. #24  
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    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by Bad Robot View Post
    But we don't have one yet and maybe never will.
    I personally doubt very much that the Alcubierre drive is physically feasible ( as opposed to being mathematically possible ). I think we should better keep looking for other alternatives.
    I agree, we need to get control of our own solar system first and talking about warp drives is really getting ahead of our selves. I think ion drives will improve and get us around the solar system, until the next better thing comes along.
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  26. #25  
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    Quote Originally Posted by Bad Robot View Post
    I agree, we need to get control of our own solar system first and talking about warp drives is really getting ahead of our selves. I think ion drives will improve and get us around the solar system, until the next better thing comes along.
    True. However, we must also consider the possibility that no FTL travel can physically exist ( we don't know enough yet about the nature of space-time to decide either way ); I have no doubt that interstellar travel will one day be achieved, but it might just be a case of very long transits at subliminal speeds. Not very "romantic", but it would do the job too.
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  27. #26  
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    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by Bad Robot View Post
    I agree, we need to get control of our own solar system first and talking about warp drives is really getting ahead of our selves. I think ion drives will improve and get us around the solar system, until the next better thing comes along.
    True. However, we must also consider the possibility that no FTL travel can physically exist ( we don't know enough yet about the nature of space-time to decide either way ); I have no doubt that interstellar travel will one day be achieved, but it might just be a case of very long transits at subliminal speeds. Not very "romantic", but it would do the job too.
    We would need a very good motivator like knowing we were traveling to an earth like world. It most likely would be a one way trip which means we would need enough people to start a viable human population along with whatever resources we could take on the trip. This would require a very large ship and more resources than just earth could provide so we still need many years experience of traveling and mining in our own solar system and in space construction. Also, we have yet never built a long term biosphere that could sustain life on it's own with out help from a planet that already does support life. For humans interstellar travel is still a long way off, but robot travel could give us a big jump on getting to some near by systems.
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    We would need a very good motivator like knowing we were traveling to an earth like world.
    and to be sure we would have to send out probes first so we have their travel time. then the return trip of the information. so even close-by stars the wait time would be 100s if not 1000s of years. do humans have an attention span that long?
    Sometimes it is better not knowing than having an answer that may be wrong.
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  29. #28  
    Forum Bachelors Degree GoldenRatio's Avatar
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    I wonder how a ship would survive for 100 or 1000's of years. You only have what you take with you. so ya know if something breaks. there isnt a repair shop, you cant call AAA. your just stuck.
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