As was foretold, we've added advertisements to the forums! If you have questions, or if you encounter any bugs, please visit this thread: https://forums.penny-arcade.com/discussion/240191/forum-advertisement-faq-and-reports-thread/

As lim (pg. -> 100) 1/(100 - pg.) we are compelled to make a new [Science] thread.

24

Posts

  • daveNYCdaveNYC Why universe hate Waspinator? Registered User regular
    Yeah, I'm totally confuzzled. Is the following correct?
    1. There's a dude, Alan, on Alpha Centauri. He's seeing both travelers taking say 15 years to get to him from Earth, or whatever.
    2. There's Bob, he's in the ramscoop lighthugger Epstein drive ship, hanging with Einstein, and the trip takes 10 years by his perspective.
    3. Then there's Chet. He's in the fancypants ship with the magic drive and the trip takes 15 years from his point of view.
    So, assuming that somehow they follow the exact same acceleration profile, leave at the same time, and spend the entire trip 100m off each other's beams, where is the potential paradox coming from? Is there an example? Like using small words and potentially some nice simple pictures or something? Because I'm not really seeing it.

    Shut up, Mr. Burton! You were not brought upon this world to get it!
  • Captain InertiaCaptain Inertia Registered User regular
    edited November 2020
    I knew Einstein would be in the one that gives him more time to pull time-pranks on Chet

    Captain Inertia on
  • AbsoluteZeroAbsoluteZero The new film by Quentin Koopantino Registered User regular
    So here's something fun to think about. Objects beyond your cosmic horizon are traveling faster than the speed of light away from you (that's why they are beyond your cosmic horizon, the light from those objects will never reach you). That also means you are traveling faster than the speed of light from the perspective of objects outside your cosmic horizon. Congratulations! You have broken the warp barrier.

    cs6f034fsffl.jpg
  • Jealous DevaJealous Deva Registered User regular
    daveNYC wrote: »
    Yeah, I'm totally confuzzled. Is the following correct?
    1. There's a dude, Alan, on Alpha Centauri. He's seeing both travelers taking say 15 years to get to him from Earth, or whatever.
    2. There's Bob, he's in the ramscoop lighthugger Epstein drive ship, hanging with Einstein, and the trip takes 10 years by his perspective.
    3. Then there's Chet. He's in the fancypants ship with the magic drive and the trip takes 15 years from his point of view.
    So, assuming that somehow they follow the exact same acceleration profile, leave at the same time, and spend the entire trip 100m off each other's beams, where is the potential paradox coming from? Is there an example? Like using small words and potentially some nice simple pictures or something? Because I'm not really seeing it.

    Thats the thing, they only stay withing 100m of each others beams from the perspective of one traveller (the warp drive guy, because he is “moving” without moving and his reference frame is from earth’s where he began). The other guy is still working with special relativity and looks out the window and sees Chet behind him. From the moment you turn on the drive you destroy the assumption that all frames of reference are symmetrical and equivalent by privileging the frame of reference the warp drive starts in, which essentially implies that from that point on there are potentially multiple distinct timelines existing in the same universe that could interact with each other.

    Here’s an explanation for a similar phenomena with wormholes and ftl communication, but note actual FTL is not required to cause issues, just breaking the equivalence of reference frames.

    https://www.npl.washington.edu/av/altvw33.html

  • SiliconStewSiliconStew Registered User regular
    Winky wrote: »
    Chanus wrote: »
    weird time travel shit isn't a paradox if it doesn't affect causality

    you can take some textbooks with you in your bubble and complete an associates degree during your travel that you wouldn't have had time to do outside the bubble but that time still occurred to you

    Thats not what happens.

    What happens is that to the guy in the bubble he literally arrives at the same time as the guy who travelled conventionally. He pulls up on the landing pad at the same time, shakes his hand, both arrive simultaneously.

    For the guy who went in the regular spaceship he gets to alpha centauri, takes a community college class, gets married, has a kid, takes a taxi 2 years later and meets warp bubble guy at the launch pad, and shakes his hand.

    At no point is there a mechanism to reconcile these alternate chains of events, both guys proceed to live the rest of their lives as if their version of things happened but somehow still occupy the same universe.

    I don't think this is how it works. If Bob were standing on Alpha Centauri he would still perceive the trip as having took you 17 years, not 15 (after he accounts for the time it took light from Earth showing you taking off to reach him). You're the only one who experiences it as 15 years.

    (Okay this is maybe fudged a little bit because it assumes Alpha Centauri and Earth are stationary relative to each other, which they are not, but they are certainly far closer to stationary relative to each other than they are relative to you and Cal.)

    Thats what normally happens in relativistic travel. Time travels slower for the traveller than either destination (note normally clocks aren’t going to be the same at all on alpha centauri or earth, they are also moving relative to each other). But because the speed of light is an inherent limiter of the speed of travel in relativity, paradoxes get rectified.

    Its totally possible from a pair of arbitrary points of view in special relativity for two observers to observe a set of events in different locations in a different order (ie from the milky way you may see a distant supernova in galaxy A occur before B, but from andromeda you may see galaxy b have a supernova before galaxy a). But because of the speed of light limiting flow of information and therefore causality itself every observer internal to the system has a consistent point of view in which causality is maintained.


    Because the alcubierre drive is letting you keep the frame of reference of Earth while physically being adjacent to alpha centauri, you are suddenly allowing paradoxes in perspective to have a meaningful impact on events, in a way that just traveling there conventionally doesn’t (because the speed of light and subjective time dilation prevents such paradoxes from occurring and actually mattering, everything “cancels out” so that a coherent time line is visible to any observer which agrees reasonably with any other observer as to “what is actually going on right now at this moment” provided they are in the same location).

    This is literally what special relativity does, and anything that bypasses it is going to need to have another mechanism to reconcile synchronicity at local distances and resolve paradoxes, or have observers at the same location disagreeing about what they are observing in the “present”.

    The immediate analysis problem is Special Relativity only applies in flat spacetime. The Alcubierre drive makes the situation most definitely not flat spacetime, so requires General Relativity to analyze. Alcubierre shows in his paper that the drive by itself cannot create a closed timeline curve (it does not allow for time travel), but included the large caveat it might be possible with other constructions to do so.

    Just remember that half the people you meet are below average intelligence.
  • redxredx I(x)=2(x)+1 whole numbersRegistered User regular
    So here's something fun to think about. Objects beyond your cosmic horizon are traveling faster than the speed of light away from you (that's why they are beyond your cosmic horizon, the light from those objects will never reach you). That also means you are traveling faster than the speed of light from the perspective of objects outside your cosmic horizon. Congratulations! You have broken the warp barrier.

    Ehh, more space is coming to exist between us and things over the horizon.

    We aren't traveling through space faster than the speed of light.

    and, there's no information that can get communicated so no paradoxes.

    This machine kills threads.
    Phoenix-D
  • Jealous DevaJealous Deva Registered User regular
    Winky wrote: »
    Chanus wrote: »
    weird time travel shit isn't a paradox if it doesn't affect causality

    you can take some textbooks with you in your bubble and complete an associates degree during your travel that you wouldn't have had time to do outside the bubble but that time still occurred to you

    Thats not what happens.

    What happens is that to the guy in the bubble he literally arrives at the same time as the guy who travelled conventionally. He pulls up on the landing pad at the same time, shakes his hand, both arrive simultaneously.

    For the guy who went in the regular spaceship he gets to alpha centauri, takes a community college class, gets married, has a kid, takes a taxi 2 years later and meets warp bubble guy at the launch pad, and shakes his hand.

    At no point is there a mechanism to reconcile these alternate chains of events, both guys proceed to live the rest of their lives as if their version of things happened but somehow still occupy the same universe.

    I don't think this is how it works. If Bob were standing on Alpha Centauri he would still perceive the trip as having took you 17 years, not 15 (after he accounts for the time it took light from Earth showing you taking off to reach him). You're the only one who experiences it as 15 years.

    (Okay this is maybe fudged a little bit because it assumes Alpha Centauri and Earth are stationary relative to each other, which they are not, but they are certainly far closer to stationary relative to each other than they are relative to you and Cal.)

    Thats what normally happens in relativistic travel. Time travels slower for the traveller than either destination (note normally clocks aren’t going to be the same at all on alpha centauri or earth, they are also moving relative to each other). But because the speed of light is an inherent limiter of the speed of travel in relativity, paradoxes get rectified.

    Its totally possible from a pair of arbitrary points of view in special relativity for two observers to observe a set of events in different locations in a different order (ie from the milky way you may see a distant supernova in galaxy A occur before B, but from andromeda you may see galaxy b have a supernova before galaxy a). But because of the speed of light limiting flow of information and therefore causality itself every observer internal to the system has a consistent point of view in which causality is maintained.


    Because the alcubierre drive is letting you keep the frame of reference of Earth while physically being adjacent to alpha centauri, you are suddenly allowing paradoxes in perspective to have a meaningful impact on events, in a way that just traveling there conventionally doesn’t (because the speed of light and subjective time dilation prevents such paradoxes from occurring and actually mattering, everything “cancels out” so that a coherent time line is visible to any observer which agrees reasonably with any other observer as to “what is actually going on right now at this moment” provided they are in the same location).

    This is literally what special relativity does, and anything that bypasses it is going to need to have another mechanism to reconcile synchronicity at local distances and resolve paradoxes, or have observers at the same location disagreeing about what they are observing in the “present”.

    The immediate analysis problem is Special Relativity only applies in flat spacetime. The Alcubierre drive makes the situation most definitely not flat spacetime, so requires General Relativity to analyze. Alcubierre shows in his paper that the drive by itself cannot create a closed timeline curve (it does not allow for time travel), but included the large caveat it might be possible with other constructions to do so.

    Alcubierre only included a single “trip” in his paper though, IIRC since other authors have shown that closed time loops are possible simply by making multiple trips in different directions. Regardless closed time loops aren’t the only potentially detectable simultaneity paradoxes.

  • Captain InertiaCaptain Inertia Registered User regular
    So warp drive travel companies will be responsible for making sure all the paradoxes are managed huh

  • SoggybiscuitSoggybiscuit 4.5 MV of POWER! Registered User regular
    All sciences and related fields are welcome for discussion.

    To start things off,at

    WARP DRIVE!

    Well, not FTL, but a good theoretical foundation for warp drive (paper isn't available or on arXiv yet):

    [snip]

    Thanks for the link. I ran across this other video in her channel that is both interesting and, at the very end, incredibly savage:


    She makes good points in this video. I think that she ignores a few caveats of her own argument though. Specifically
    • Large particle colliders are capital projects, and can take decades to design, construct, and commission. If you think you'll have something that is testable in 10 years, you should have designed the accelerator for it 10 years ago and be constructing it now.
    • The design, construction, maintenance, and operation of particle colliders has an enormous amount of required institutional knowledge and expertise to be economical. Go for too long and this knowledge quits, retires, and dies, setting back future efforts.
    • Political will that exists today is not necessarily going to be there when you are ready to build a new accelerator. This can go both ways, but elected officials will sell their soul to Maxwell's Demon to keep getting elected.
    • Speaking of politics, miss the opportunity to build something like this and someone else may do it. The owner of this equipment may engage in actions that are antithetical to your values and it might be dangerous politically, physically, and emotionally to work with them. See: China and current situation with the Uighur people.

    Steam - Synthetic Violence | XBOX Live - Cannonfuse | PSN - CastleBravo | Twitch - SoggybiscuitPA
  • WinkyWinky rRegistered User regular
    I'd be interested in her idea of how specifically the money could be better spent. I mean, "we can't come up with any other promising areas to look at so we want to collide particles faster and hope we see something" is dumb, but only if there are other better options for driving the science forward. I suppose there are merits to "instead of just building a bigger version of what you already have, spend some time thinking about other things you could build so you're not stuck on this own track".

    spool32
  • AbsoluteZeroAbsoluteZero The new film by Quentin Koopantino Registered User regular
    redx wrote: »
    So here's something fun to think about. Objects beyond your cosmic horizon are traveling faster than the speed of light away from you (that's why they are beyond your cosmic horizon, the light from those objects will never reach you). That also means you are traveling faster than the speed of light from the perspective of objects outside your cosmic horizon. Congratulations! You have broken the warp barrier.

    Ehh, more space is coming to exist between us and things over the horizon.

    We aren't traveling through space faster than the speed of light.

    and, there's no information that can get communicated so no paradoxes.

    We are not traveling through space, we are riding on spacetime that itself expands faster than the speed of light. The principal is not far off from a warp drive (e.g. spacetime moves, you don't move within spacetime.).

    cs6f034fsffl.jpg
  • PhyphorPhyphor Building Planet Busters Tasting FruitRegistered User regular
    Winky wrote: »
    Chanus wrote: »
    weird time travel shit isn't a paradox if it doesn't affect causality

    you can take some textbooks with you in your bubble and complete an associates degree during your travel that you wouldn't have had time to do outside the bubble but that time still occurred to you

    Thats not what happens.

    What happens is that to the guy in the bubble he literally arrives at the same time as the guy who travelled conventionally. He pulls up on the landing pad at the same time, shakes his hand, both arrive simultaneously.

    For the guy who went in the regular spaceship he gets to alpha centauri, takes a community college class, gets married, has a kid, takes a taxi 2 years later and meets warp bubble guy at the launch pad, and shakes his hand.

    At no point is there a mechanism to reconcile these alternate chains of events, both guys proceed to live the rest of their lives as if their version of things happened but somehow still occupy the same universe.

    I don't think this is how it works. If Bob were standing on Alpha Centauri he would still perceive the trip as having took you 17 years, not 15 (after he accounts for the time it took light from Earth showing you taking off to reach him). You're the only one who experiences it as 15 years.

    (Okay this is maybe fudged a little bit because it assumes Alpha Centauri and Earth are stationary relative to each other, which they are not, but they are certainly far closer to stationary relative to each other than they are relative to you and Cal.)

    Thats what normally happens in relativistic travel. Time travels slower for the traveller than either destination (note normally clocks aren’t going to be the same at all on alpha centauri or earth, they are also moving relative to each other). But because the speed of light is an inherent limiter of the speed of travel in relativity, paradoxes get rectified.

    Its totally possible from a pair of arbitrary points of view in special relativity for two observers to observe a set of events in different locations in a different order (ie from the milky way you may see a distant supernova in galaxy A occur before B, but from andromeda you may see galaxy b have a supernova before galaxy a). But because of the speed of light limiting flow of information and therefore causality itself every observer internal to the system has a consistent point of view in which causality is maintained.


    Because the alcubierre drive is letting you keep the frame of reference of Earth while physically being adjacent to alpha centauri, you are suddenly allowing paradoxes in perspective to have a meaningful impact on events, in a way that just traveling there conventionally doesn’t (because the speed of light and subjective time dilation prevents such paradoxes from occurring and actually mattering, everything “cancels out” so that a coherent time line is visible to any observer which agrees reasonably with any other observer as to “what is actually going on right now at this moment” provided they are in the same location).

    This is literally what special relativity does, and anything that bypasses it is going to need to have another mechanism to reconcile synchronicity at local distances and resolve paradoxes, or have observers at the same location disagreeing about what they are observing in the “present”.

    The immediate analysis problem is Special Relativity only applies in flat spacetime. The Alcubierre drive makes the situation most definitely not flat spacetime, so requires General Relativity to analyze. Alcubierre shows in his paper that the drive by itself cannot create a closed timeline curve (it does not allow for time travel), but included the large caveat it might be possible with other constructions to do so.

    Alcubierre only included a single “trip” in his paper though, IIRC since other authors have shown that closed time loops are possible simply by making multiple trips in different directions. Regardless closed time loops aren’t the only potentially detectable simultaneity paradoxes.

    That should only be a problem with a FTL version. Sublight is by definition within a light cone

  • Jealous DevaJealous Deva Registered User regular
    Phyphor wrote: »
    Winky wrote: »
    Chanus wrote: »
    weird time travel shit isn't a paradox if it doesn't affect causality

    you can take some textbooks with you in your bubble and complete an associates degree during your travel that you wouldn't have had time to do outside the bubble but that time still occurred to you

    Thats not what happens.

    What happens is that to the guy in the bubble he literally arrives at the same time as the guy who travelled conventionally. He pulls up on the landing pad at the same time, shakes his hand, both arrive simultaneously.

    For the guy who went in the regular spaceship he gets to alpha centauri, takes a community college class, gets married, has a kid, takes a taxi 2 years later and meets warp bubble guy at the launch pad, and shakes his hand.

    At no point is there a mechanism to reconcile these alternate chains of events, both guys proceed to live the rest of their lives as if their version of things happened but somehow still occupy the same universe.

    I don't think this is how it works. If Bob were standing on Alpha Centauri he would still perceive the trip as having took you 17 years, not 15 (after he accounts for the time it took light from Earth showing you taking off to reach him). You're the only one who experiences it as 15 years.

    (Okay this is maybe fudged a little bit because it assumes Alpha Centauri and Earth are stationary relative to each other, which they are not, but they are certainly far closer to stationary relative to each other than they are relative to you and Cal.)

    Thats what normally happens in relativistic travel. Time travels slower for the traveller than either destination (note normally clocks aren’t going to be the same at all on alpha centauri or earth, they are also moving relative to each other). But because the speed of light is an inherent limiter of the speed of travel in relativity, paradoxes get rectified.

    Its totally possible from a pair of arbitrary points of view in special relativity for two observers to observe a set of events in different locations in a different order (ie from the milky way you may see a distant supernova in galaxy A occur before B, but from andromeda you may see galaxy b have a supernova before galaxy a). But because of the speed of light limiting flow of information and therefore causality itself every observer internal to the system has a consistent point of view in which causality is maintained.


    Because the alcubierre drive is letting you keep the frame of reference of Earth while physically being adjacent to alpha centauri, you are suddenly allowing paradoxes in perspective to have a meaningful impact on events, in a way that just traveling there conventionally doesn’t (because the speed of light and subjective time dilation prevents such paradoxes from occurring and actually mattering, everything “cancels out” so that a coherent time line is visible to any observer which agrees reasonably with any other observer as to “what is actually going on right now at this moment” provided they are in the same location).

    This is literally what special relativity does, and anything that bypasses it is going to need to have another mechanism to reconcile synchronicity at local distances and resolve paradoxes, or have observers at the same location disagreeing about what they are observing in the “present”.

    The immediate analysis problem is Special Relativity only applies in flat spacetime. The Alcubierre drive makes the situation most definitely not flat spacetime, so requires General Relativity to analyze. Alcubierre shows in his paper that the drive by itself cannot create a closed timeline curve (it does not allow for time travel), but included the large caveat it might be possible with other constructions to do so.

    Alcubierre only included a single “trip” in his paper though, IIRC since other authors have shown that closed time loops are possible simply by making multiple trips in different directions. Regardless closed time loops aren’t the only potentially detectable simultaneity paradoxes.

    That should only be a problem with a FTL version. Sublight is by definition within a light cone

    You won’t get direct into the past time travel but you can still get a lot of funky things going on by breaking equivalence/symmetry between frames of reference.

  • BrodyBrody The Watch The First ShoreRegistered User regular
    daveNYC wrote: »
    Yeah, I'm totally confuzzled. Is the following correct?
    1. There's a dude, Alan, on Alpha Centauri. He's seeing both travelers taking say 15 years to get to him from Earth, or whatever.
    2. There's Bob, he's in the ramscoop lighthugger Epstein drive ship, hanging with Einstein, and the trip takes 10 years by his perspective.
    3. Then there's Chet. He's in the fancypants ship with the magic drive and the trip takes 15 years from his point of view.
    So, assuming that somehow they follow the exact same acceleration profile, leave at the same time, and spend the entire trip 100m off each other's beams, where is the potential paradox coming from? Is there an example? Like using small words and potentially some nice simple pictures or something? Because I'm not really seeing it.

    Thats the thing, they only stay withing 100m of each others beams from the perspective of one traveller (the warp drive guy, because he is “moving” without moving and his reference frame is from earth’s where he began). The other guy is still working with special relativity and looks out the window and sees Chet behind him. From the moment you turn on the drive you destroy the assumption that all frames of reference are symmetrical and equivalent by privileging the frame of reference the warp drive starts in, which essentially implies that from that point on there are potentially multiple distinct timelines existing in the same universe that could interact with each other.

    Here’s an explanation for a similar phenomena with wormholes and ftl communication, but note actual FTL is not required to cause issues, just breaking the equivalence of reference frames.

    https://www.npl.washington.edu/av/altvw33.html

    Just because Bob only experiences 10 years, doesn't mean he is getting there any earlier. The time from a universal reference frame would be the same as long as you aren't exceeding the speed of light. Its just that Bob would experiencing a contraction of that time, while Chet is in the new fancy ship that negates contractions in a local frame. They both still take however many time units to travel the same distance, as they are both travelling the same speed. Looking at each other while travelling will be more complicated because of the alcubiere(sp) distortion.

    I haven't watched the video yet, but I don't see why you would choose to avoid time dilation. It is basically only ever a plus? Even jumping around the solar system, it basically means you only had to endure 5 minutes of travel instead of 20 or w/e.

    "I will write your name in the ruin of them. I will paint you across history in the color of their blood."

    The Monster Baru Cormorant - Seth Dickinson

    Steam: Korvalain
  • SoggybiscuitSoggybiscuit 4.5 MV of POWER! Registered User regular
    Winky wrote: »
    I'd be interested in her idea of how specifically the money could be better spent. I mean, "we can't come up with any other promising areas to look at so we want to collide particles faster and hope we see something" is dumb, but only if there are other better options for driving the science forward. I suppose there are merits to "instead of just building a bigger version of what you already have, spend some time thinking about other things you could build so you're not stuck on this own track".

    She mentions high precision physics. High precision nuclear/particle physics is kinda funny though, most of the effort goes into reducing background from external sources, not building sensitive detectors/electronics/etc. because we are really good at that already. Also she talks about putting more money into theory research.

    Both of which can be done much cheaper than a new particle accelerator. Theory research suffers from the same problem, perhaps even more so that just building bigger colliders. We have no guarantees that theorists will produce anything testable in the next 50 years, either. High precision physics will hit a limit and after that you won't have any more advancement because you can only reduce the natural background so much.

    Steam - Synthetic Violence | XBOX Live - Cannonfuse | PSN - CastleBravo | Twitch - SoggybiscuitPA
  • chrisnlchrisnl Registered User regular
    Brody wrote: »
    daveNYC wrote: »
    Yeah, I'm totally confuzzled. Is the following correct?
    1. There's a dude, Alan, on Alpha Centauri. He's seeing both travelers taking say 15 years to get to him from Earth, or whatever.
    2. There's Bob, he's in the ramscoop lighthugger Epstein drive ship, hanging with Einstein, and the trip takes 10 years by his perspective.
    3. Then there's Chet. He's in the fancypants ship with the magic drive and the trip takes 15 years from his point of view.
    So, assuming that somehow they follow the exact same acceleration profile, leave at the same time, and spend the entire trip 100m off each other's beams, where is the potential paradox coming from? Is there an example? Like using small words and potentially some nice simple pictures or something? Because I'm not really seeing it.

    Thats the thing, they only stay withing 100m of each others beams from the perspective of one traveller (the warp drive guy, because he is “moving” without moving and his reference frame is from earth’s where he began). The other guy is still working with special relativity and looks out the window and sees Chet behind him. From the moment you turn on the drive you destroy the assumption that all frames of reference are symmetrical and equivalent by privileging the frame of reference the warp drive starts in, which essentially implies that from that point on there are potentially multiple distinct timelines existing in the same universe that could interact with each other.

    Here’s an explanation for a similar phenomena with wormholes and ftl communication, but note actual FTL is not required to cause issues, just breaking the equivalence of reference frames.

    https://www.npl.washington.edu/av/altvw33.html

    Just because Bob only experiences 10 years, doesn't mean he is getting there any earlier. The time from a universal reference frame would be the same as long as you aren't exceeding the speed of light. Its just that Bob would experiencing a contraction of that time, while Chet is in the new fancy ship that negates contractions in a local frame. They both still take however many time units to travel the same distance, as they are both travelling the same speed. Looking at each other while travelling will be more complicated because of the alcubiere(sp) distortion.

    I haven't watched the video yet, but I don't see why you would choose to avoid time dilation. It is basically only ever a plus? Even jumping around the solar system, it basically means you only had to endure 5 minutes of travel instead of 20 or w/e.

    I think, but I'm not that kind of scientist and don't know for sure, that one of the benefits of the warp system is that the people inside are shielded from the momentum change as well so that you can have absurd levels of acceleration and not end up a smear on the back side of the vehicle (or the front side when you suddenly stop). It's all extremely hypothetical, but from what I think I understood the really exciting part for traveling in-system is that travel times would be way way shorter because of not having to worry about the transported objects being subject to acceleration. For example if you were to do 1g acceleration between Earth and Mars (with roughly half the distance spent decelerating) it would take a minimum of 1d 21h and some change. With a sub-light warp drive as described, you could get there much more quickly, or to the asteroid belt or wherever.

    steam_sig.png
    Morninglord
  • MorninglordMorninglord Registered User regular
    edited November 2020
    chrisnl wrote: »
    Brody wrote: »
    daveNYC wrote: »
    Yeah, I'm totally confuzzled. Is the following correct?
    1. There's a dude, Alan, on Alpha Centauri. He's seeing both travelers taking say 15 years to get to him from Earth, or whatever.
    2. There's Bob, he's in the ramscoop lighthugger Epstein drive ship, hanging with Einstein, and the trip takes 10 years by his perspective.
    3. Then there's Chet. He's in the fancypants ship with the magic drive and the trip takes 15 years from his point of view.
    So, assuming that somehow they follow the exact same acceleration profile, leave at the same time, and spend the entire trip 100m off each other's beams, where is the potential paradox coming from? Is there an example? Like using small words and potentially some nice simple pictures or something? Because I'm not really seeing it.

    Thats the thing, they only stay withing 100m of each others beams from the perspective of one traveller (the warp drive guy, because he is “moving” without moving and his reference frame is from earth’s where he began). The other guy is still working with special relativity and looks out the window and sees Chet behind him. From the moment you turn on the drive you destroy the assumption that all frames of reference are symmetrical and equivalent by privileging the frame of reference the warp drive starts in, which essentially implies that from that point on there are potentially multiple distinct timelines existing in the same universe that could interact with each other.

    Here’s an explanation for a similar phenomena with wormholes and ftl communication, but note actual FTL is not required to cause issues, just breaking the equivalence of reference frames.

    https://www.npl.washington.edu/av/altvw33.html

    Just because Bob only experiences 10 years, doesn't mean he is getting there any earlier. The time from a universal reference frame would be the same as long as you aren't exceeding the speed of light. Its just that Bob would experiencing a contraction of that time, while Chet is in the new fancy ship that negates contractions in a local frame. They both still take however many time units to travel the same distance, as they are both travelling the same speed. Looking at each other while travelling will be more complicated because of the alcubiere(sp) distortion.

    I haven't watched the video yet, but I don't see why you would choose to avoid time dilation. It is basically only ever a plus? Even jumping around the solar system, it basically means you only had to endure 5 minutes of travel instead of 20 or w/e.

    I think, but I'm not that kind of scientist and don't know for sure, that one of the benefits of the warp system is that the people inside are shielded from the momentum change as well so that you can have absurd levels of acceleration and not end up a smear on the back side of the vehicle (or the front side when you suddenly stop). It's all extremely hypothetical, but from what I think I understood the really exciting part for traveling in-system is that travel times would be way way shorter because of not having to worry about the transported objects being subject to acceleration. For example if you were to do 1g acceleration between Earth and Mars (with roughly half the distance spent decelerating) it would take a minimum of 1d 21h and some change. With a sub-light warp drive as described, you could get there much more quickly, or to the asteroid belt or wherever.

    This. If you could, for example, instantly hit 0.5c and instantly turn it off, you'd reach mars on closest approach in around 6 minutes. That's absolutely massive and if they manage to make a sub-light warp drive, and power it, would absolutely be used constantly. Time travel and paradoxes be damned. It'd just happen.

    It'd be like the intrasolar cruise drives you get in space trading games that have a different method of travel for getting between solar systems, but once you are in asystem you use this super drive (usually called Cruise or something) to travel between planets. That's basically what we are talking about here.

    Morninglord on
    (PSN: Morninglord) (Steam: Morninglord) (WiiU: Morninglord22) I like to record and toss up a lot of random gaming videos here.
  • BrodyBrody The Watch The First ShoreRegistered User regular
    chrisnl wrote: »
    Brody wrote: »
    daveNYC wrote: »
    Yeah, I'm totally confuzzled. Is the following correct?
    1. There's a dude, Alan, on Alpha Centauri. He's seeing both travelers taking say 15 years to get to him from Earth, or whatever.
    2. There's Bob, he's in the ramscoop lighthugger Epstein drive ship, hanging with Einstein, and the trip takes 10 years by his perspective.
    3. Then there's Chet. He's in the fancypants ship with the magic drive and the trip takes 15 years from his point of view.
    So, assuming that somehow they follow the exact same acceleration profile, leave at the same time, and spend the entire trip 100m off each other's beams, where is the potential paradox coming from? Is there an example? Like using small words and potentially some nice simple pictures or something? Because I'm not really seeing it.

    Thats the thing, they only stay withing 100m of each others beams from the perspective of one traveller (the warp drive guy, because he is “moving” without moving and his reference frame is from earth’s where he began). The other guy is still working with special relativity and looks out the window and sees Chet behind him. From the moment you turn on the drive you destroy the assumption that all frames of reference are symmetrical and equivalent by privileging the frame of reference the warp drive starts in, which essentially implies that from that point on there are potentially multiple distinct timelines existing in the same universe that could interact with each other.

    Here’s an explanation for a similar phenomena with wormholes and ftl communication, but note actual FTL is not required to cause issues, just breaking the equivalence of reference frames.

    https://www.npl.washington.edu/av/altvw33.html

    Just because Bob only experiences 10 years, doesn't mean he is getting there any earlier. The time from a universal reference frame would be the same as long as you aren't exceeding the speed of light. Its just that Bob would experiencing a contraction of that time, while Chet is in the new fancy ship that negates contractions in a local frame. They both still take however many time units to travel the same distance, as they are both travelling the same speed. Looking at each other while travelling will be more complicated because of the alcubiere(sp) distortion.

    I haven't watched the video yet, but I don't see why you would choose to avoid time dilation. It is basically only ever a plus? Even jumping around the solar system, it basically means you only had to endure 5 minutes of travel instead of 20 or w/e.

    I think, but I'm not that kind of scientist and don't know for sure, that one of the benefits of the warp system is that the people inside are shielded from the momentum change as well so that you can have absurd levels of acceleration and not end up a smear on the back side of the vehicle (or the front side when you suddenly stop). It's all extremely hypothetical, but from what I think I understood the really exciting part for traveling in-system is that travel times would be way way shorter because of not having to worry about the transported objects being subject to acceleration. For example if you were to do 1g acceleration between Earth and Mars (with roughly half the distance spent decelerating) it would take a minimum of 1d 21h and some change. With a sub-light warp drive as described, you could get there much more quickly, or to the asteroid belt or wherever.

    Sure, but iirc that's always been an assumed aspect of an Alcbuierre drive. Also, it's probably be best if you could do both, although I guess at .995 C you would only take 6 hours, so maybe having 0g wouldn't be that big of a deal.

    "I will write your name in the ruin of them. I will paint you across history in the color of their blood."

    The Monster Baru Cormorant - Seth Dickinson

    Steam: Korvalain
  • MorninglordMorninglord Registered User regular
    edited November 2020
    https://www.space.com/24701-how-long-does-it-take-to-get-to-mars.html
    The speed of light

    Light travels at approximately 186,282 miles per second (299,792 km per second). Therefore, a light shining from the surface of Mars would take the following amount of time to reach Earth (or vice versa):

    Closest possible approach: 182 seconds, or 3.03 minutes
    Closest recorded approach: 187 seconds, or 3.11 minutes
    Farthest approach: 1,342 seconds, or 22.4 minutes
    On average: 751 seconds, or just over 12.5 minutes

    To use in calculations. 0.995 of c is much faster than 6 hours. Try around half an hour on average.

    This would shrink the solar system substantially. Even if all they can do is skip acceleration effects and can't really get above our current rockets acceleration speeds (without human pilots, so not limited by the paltry g forces they can achieve with squishies inside), it'd still dramatically reduce the time it takes to get places.

    Morninglord on
    (PSN: Morninglord) (Steam: Morninglord) (WiiU: Morninglord22) I like to record and toss up a lot of random gaming videos here.
  • webguy20webguy20 I spend too much time on the Internet Registered User regular
    Lets go pop over to mars for some burgers and beers.

    Steam ID: Webguy20
    Origin ID: Discgolfer27
    Untappd ID: Discgolfer1981
    MorninglordCaptain InertiaSpecial Kspool32GiantGeek2020
  • BrodyBrody The Watch The First ShoreRegistered User regular
    edited November 2020
    https://www.space.com/24701-how-long-does-it-take-to-get-to-mars.html
    The speed of light

    Light travels at approximately 186,282 miles per second (299,792 km per second). Therefore, a light shining from the surface of Mars would take the following amount of time to reach Earth (or vice versa):

    Closest possible approach: 182 seconds, or 3.03 minutes
    Closest recorded approach: 187 seconds, or 3.11 minutes
    Farthest approach: 1,342 seconds, or 22.4 minutes
    On average: 751 seconds, or just over 12.5 minutes

    To use in calculations. 0.995 of c is much faster than 6 hours. Try around half an hour on average.

    This would shrink the solar system substantially. Even if all they can do is skip acceleration effects and can't really get above our current rockets acceleration speeds (without human pilots, so not limited by the paltry g forces they can achieve with squishies inside), it'd still dramatically reduce the time it takes to get places.

    Sorry, I thought I had read somewhere that .995c is about 1/10th in dilation.

    Actually, provided t = t0/(1-v^2/c^2)^1/2 is the correct equation for calculating time dilation, it would take about 4.5 hours. Moving at .995c results in moving object experiencing 1/10th of the observers time.

    Brody on
    "I will write your name in the ruin of them. I will paint you across history in the color of their blood."

    The Monster Baru Cormorant - Seth Dickinson

    Steam: Korvalain
  • Jealous DevaJealous Deva Registered User regular
    If the timey stuff works out (which I guess if you are using shittons of negative mass in the drive maybe it could balance, I guess the presence of that kind of anti-gravitational density in the bubble itself might give enough of a bending of spacetime that it all works out or there may be unknown physics that rectifies it, especially since the existence of negative exotic matter would require rewriting a lot of physics anyway) you still need massive fucktons of energy to do it? If you’re burning jupiter masses of exotic negative matter every trip to mars you make it seems like that may be a problem?

  • Captain InertiaCaptain Inertia Registered User regular
    edited November 2020
    If the timey stuff works out (which I guess if you are using shittons of negative mass in the drive maybe it could balance, I guess the presence of that kind of anti-gravitational density in the bubble itself might give enough of a bending of spacetime that it all works out or there may be unknown physics that rectifies it, especially since the existence of negative exotic matter would require rewriting a lot of physics anyway) you still need massive fucktons of energy to do it? If you’re burning jupiter masses of exotic negative matter every trip to mars you make it seems like that may be a problem?

    Pfffft we got enough energy for like 3 generations to profit from those losers in gen 4 and up can eat dirty space genitalia

    Captain Inertia on
  • MorninglordMorninglord Registered User regular
    edited November 2020
    If the timey stuff works out (which I guess if you are using shittons of negative mass in the drive maybe it could balance, I guess the presence of that kind of anti-gravitational density in the bubble itself might give enough of a bending of spacetime that it all works out or there may be unknown physics that rectifies it, especially since the existence of negative exotic matter would require rewriting a lot of physics anyway) you still need massive fucktons of energy to do it? If you’re burning jupiter masses of exotic negative matter every trip to mars you make it seems like that may be a problem?

    The video in the op showed that a sublight speed warp drive does not need exotic matter or negative energy and the math indicates it can be done somewhat pragmatically.

    Negative energy / exotic matter is only required for faster than light travel. This drive will require energy and matter types we could potentially achieve without inventing a new physics. It'll just be limited to below c.

    Morninglord on
    (PSN: Morninglord) (Steam: Morninglord) (WiiU: Morninglord22) I like to record and toss up a lot of random gaming videos here.
  • electricitylikesmeelectricitylikesme Registered User regular
    Basically any sort of potentially reactionless drive for space travel world be a huge deal. If you can travel through space without tossing matter out the back (or doing so very efficiently) then that is an absolute game changer.

    MorninglordGennenalyse Rueben
  • SyngyneSyngyne Registered User regular
    Basically any sort of potentially reactionless drive for space travel world be a huge deal. If you can travel through space without tossing matter out the back (or doing so very efficiently) then that is an absolute game changer.

    But this would still be happening.

    You'd be chucking our current understanding of physics out the airlock.

    5gsowHm.png
    webguy20AbsoluteZeroMorninglordMonwynspool32GiantGeek2020TofystedethHeffling
  • MorninglordMorninglord Registered User regular
    edited November 2020
    Syngyne wrote: »
    Basically any sort of potentially reactionless drive for space travel world be a huge deal. If you can travel through space without tossing matter out the back (or doing so very efficiently) then that is an absolute game changer.

    But this would still be happening.

    You'd be chucking our current understanding of physics out the airlock.

    Haha you joke but I think this is actually within our current understanding of physics. That's kinda why its a big deal that the math works. That math is current physics. If it works, we gravy.

    Morninglord on
    (PSN: Morninglord) (Steam: Morninglord) (WiiU: Morninglord22) I like to record and toss up a lot of random gaming videos here.
  • Captain InertiaCaptain Inertia Registered User regular
    Well the math might work but what about the actual engineering and fabrication

  • HevachHevach Registered User regular
    Well the math might work but what about the actual engineering and fabrication

    Surprisingly simple... provided you can source tachyonic exotic matter, which shouldn't be able to exist naturally and cannot be created by any interaction involving any particles in the standard model.

    Riding a magical flying unicorn is easy once you find a magical flying unicorn.

    zagdrobAbsoluteZeroElvenshaekime
  • MorninglordMorninglord Registered User regular
    Hevach wrote: »
    Well the math might work but what about the actual engineering and fabrication

    Surprisingly simple... provided you can source tachyonic exotic matter, which shouldn't be able to exist naturally and cannot be created by any interaction involving any particles in the standard model.

    Riding a magical flying unicorn is easy once you find a magical flying unicorn.

    Im not sure how many times I have to say you dont need exotic matter for this solution to work before it sinks in.

    But Im wondering at this point if it ever will.

    (PSN: Morninglord) (Steam: Morninglord) (WiiU: Morninglord22) I like to record and toss up a lot of random gaming videos here.
  • Jealous DevaJealous Deva Registered User regular
    edited November 2020
    Syngyne wrote: »
    Basically any sort of potentially reactionless drive for space travel world be a huge deal. If you can travel through space without tossing matter out the back (or doing so very efficiently) then that is an absolute game changer.

    But this would still be happening.

    You'd be chucking our current understanding of physics out the airlock.

    Haha you joke but I think this is actually within our current understanding of physics. That's kinda why its a big deal that the math works. That math is current physics. If it works, we gravy.

    I don’t know that the math really does work, the original video just barely glances over a positive energy warp bubble without any detail or explanation.

    Alcubierre’s solution definitely involves the kind of space time warping you’d need negative mass for. The only other things I have heard basically involve using shit tons of regular energy in certain configurations to basically use quantum effects to “trick” the universe into having the energy of certain areas average out negative. Which is still using negative energy, just generating it in situ.

    Unless the paper referred to is actually published and checks out we don’t have a lot to go on.

    And even so a lot of the physics involved in things like this is conceptual stuff, we don’t have a unification theory yet and without one (or alternatively massive galactic scale amounts of energy to throw at experimental physics) the unknown interactions between relativity and quantum mechanics makes a lot of this stuff unverifiable.

    Edit:

    It may be useful to talk a bit about why physicists find these kind of things interesting.


    Relativity (general and special) has as axiomatic two things

    1. All inertial frames of reference are equivalent. The laws of physics do not vary by speed or direction of motion of an object
    2. The speed of light is invariant from any inertial frame of reference.


    Wormholes, warp drives, etc show that there are solutions to the equations of general relativity that violate axiom #1.

    This does not necessarily imply that those solutions to the equations work in real life (although it doesn’t rule it out either). It just implies that relativity is not a complete theory and has internal inconsistencies that different or refined physics are needed to explain.

    Its a guide post for future work, saying basically “the equations of relativity imply that the axioms of relativity may not be completely true in all cases, do we need to clarify or redefine the axioms, or are the axioms right and we need some other physics to explain why these things are impossible?”

    Jealous Deva on
    AbsoluteZero
  • HevachHevach Registered User regular
    Hevach wrote: »
    Well the math might work but what about the actual engineering and fabrication

    Surprisingly simple... provided you can source tachyonic exotic matter, which shouldn't be able to exist naturally and cannot be created by any interaction involving any particles in the standard model.

    Riding a magical flying unicorn is easy once you find a magical flying unicorn.

    Im not sure how many times I have to say you dont need exotic matter for this solution to work before it sinks in.

    But Im wondering at this point if it ever will.

    Well, the authors of this new paper still say it requires negative mass/energy, which is the definition of exotic matter. So probably you'll need to say it until the paper makes it through to publication and says something new.

  • ChanusChanus I've seen things... Registered User regular
    my understanding is it is saying it would need negative mass to exceed light speed motion, but it does not if you are not trying to do that

    it's basically Alcubierre's drive at a significant fraction of light speed and thus just going really fast but not doing anything impossible

    Allegedly a voice of reason.
  • HevachHevach Registered User regular
    edited November 2020
    I mean, we're arguing about a partial statement on an unpublished paper, so there's a lot waiting on full information, but that's not my read. The negative mass isn't required to exceed the speed of light, it's what creates the wall. Subluminal alcubierre drive isn't a new idea, it's was first proposed as a solution to the horizon problem (under Alcubierre's original calculations the bubble had to be stopped from the outside, meaning threading a needle on the "gate" and if you miss you just zip off into infinity, later ideas have shown it can be broken by shooting another bubble at it from the inside) and has been more recently cited as a practical limitation, since waste heat cannot leave the bubble while it's closed, superluminal speeds would mean the inside quickly heats up to near stellar temperatures.

    Hevach on
  • SoggybiscuitSoggybiscuit 4.5 MV of POWER! Registered User regular
    The warp drive paper is unpublished but undergoing peer review (?). A cursory search of arxiv didn't turn up anything either. I think Albecurrie's original paper is on there now.

    Steam - Synthetic Violence | XBOX Live - Cannonfuse | PSN - CastleBravo | Twitch - SoggybiscuitPA
  • tbloxhamtbloxham Registered User regular
    The way to resolve these weird time things is to consider that the universe doesn’t care how fast you think you are going. Here’s what it cares about.

    1) no going faster than light speed
    2) if you look at someone, you see light speed as light speed
    3) if someone looks at you, they see light speed as light speed

    If you are inside a warp bubble, then you can see no one else and no one else can see you. The weird time dilation required to fix the light speed issue doesn’t matter.

    Alpha centuri person looks through their telescopes at the two spaceships and says, both these spaceships took 15 years to get here. Normal spaceship guy says, no it didn’t, it took 12 years. Warp bubble spaceship guy says, no it didn’t, it took 17 years. Earth person watching says, Warp Bubble guy is right, it took 17 years. (Assuming everyone just times things using a stopwatch based on when they saw the ship leave vs when they saw it arrive)

    No one has created a meaningful paradox here. No one gets extra time to do a degree on alpha centuri. They just disagree how long the trip took. And, “I disagree how long this journey lasted” is not a meaningful paradox.

    "That is cool" - Abraham Lincoln
    ChanusMeeqe
  • Captain InertiaCaptain Inertia Registered User regular
    Where does light get off, I mean

    What makes light so much better than the rest of us, huh

    Monwyn
  • AiouaAioua Ora Occidens Ora OptimaRegistered User regular
    Where does light get off, I mean

    What makes light so much better than the rest of us, huh

    lack of mass, mainly

    life's a game that you're bound to lose / like using a hammer to pound in screws
    fuck up once and you break your thumb / if you're happy at all then you're god damn dumb
    that's right we're on a fucked up cruise / God is dead but at least we have booze
    bad things happen, no one knows why / the sun burns out and everyone dies
    ChanusAimMonwynGiantGeek2020Gennenalyse Rueben
  • Captain InertiaCaptain Inertia Registered User regular
    Of course those asshole photons are mass-shamers

    ElvenshaeChanusBrodyKruite
  • BrodyBrody The Watch The First ShoreRegistered User regular
    tbloxham wrote: »
    The way to resolve these weird time things is to consider that the universe doesn’t care how fast you think you are going. Here’s what it cares about.

    1) no going faster than light speed
    2) if you look at someone, you see light speed as light speed
    3) if someone looks at you, they see light speed as light speed

    If you are inside a warp bubble, then you can see no one else and no one else can see you. The weird time dilation required to fix the light speed issue doesn’t matter.

    Alpha centuri person looks through their telescopes at the two spaceships and says, both these spaceships took 15 years to get here. Normal spaceship guy says, no it didn’t, it took 12 years. Warp bubble spaceship guy says, no it didn’t, it took 17 years. Earth person watching says, Warp Bubble guy is right, it took 17 years. (Assuming everyone just times things using a stopwatch based on when they saw the ship leave vs when they saw it arrive)

    No one has created a meaningful paradox here. No one gets extra time to do a degree on alpha centuri. They just disagree how long the trip took. And, “I disagree how long this journey lasted” is not a meaningful paradox.

    I think the "earning a degree" thing was during travel. You could indeed, if you were travelling in a bubble that negated reference frame dilation, spend that extra time learning. But you are also however many years older biologically as well, so if we haven't solved human senescence, you are that much closer to death as well.

    "I will write your name in the ruin of them. I will paint you across history in the color of their blood."

    The Monster Baru Cormorant - Seth Dickinson

    Steam: Korvalain
Sign In or Register to comment.