7 ms·

We're not going to be intergalactic by year 7298 for the simple fact that the Milky Way is 100000 light years across and traveling faster than light is physical

We're not going to be intergalactic by year 7298 for the simple fact that the Milky Way is 100000 light years across and traveling faster than light is physically forbidden

colordrops 4y ago
You really think our model of reality and what is possible will apply in 5,276 years? What did we understand 5,276 years ago? Most certainly countless things that we have now would be considered impossible or witchcraft back then.
- michaelmrose 4y ago
  If faster than light travel was possible any single species who discovered it would be able to cover an appreciable portion of the galaxy in only a few thousand years out of billions. Either life is virtually non-existent thus far, virtually always suicidal, or discovering it is tremendously unlikely. Neither of the last two bode well for us. It seems to me most likely that ftl suggestions an empty universe or one in which we too are likely to die without learning it.
  - shepherdjerred 4y ago
    You’re assuming that all species seek to grow infinitely. What’s wrong with a species of sentient house cats that just want to nap all day?
    - geertj 4y ago
      > What’s wrong with a species of sentient house cats that just want to nap all day? Nothing wrong with that, but if life is common, you’d need all life to be like that to explain the Fermi paradox, which seems unlikely.
      - colordrops 4y ago
        It could also be that the technology to achieve FTL is just over a threshold where the civilization would be unrecognizable to us as humans. We aren't far from such technology already. For instance imagine just a few generations of biotech and computational technology - it may already be enough for us to transform and evolve into some biomechanical hive that bears little resemblance to our current selves. It could also be that once you are advanced enough, you transcend this physical universe. For example, the entire universe to a deep sea squid is cold dark water without much other life. They have no way to comprehend that there is so much more to reality. They just aren't capable of it. We are not special and also likely not able to detect or comprehend other levels of reality that would be more vast and interesting to advanced beings than simple FTL leaps around the galaxy. Perhaps they just aren't interested in our little ant hill the milky way. The lack of imagination around what is possible and the supposed paradox posited by Fermi is disheartening.
        geertj 4y ago
        > The lack of imagination around what is possible and the supposed paradox posited by Fermi is disheartening. I think similar reasoning could apply though. If advanced civilizations escape into a different dimension or state of being where they are undetectable, we’d need all of them to do that to explain the Fermi paradox.
        michaelmrose 4y ago
        Exactly. Life being rare and spread out, space requiring enormous resources to move between stars, most species never outgrowing their backyards seems like it could credibly explain the paradox without FTL.
        colordrops 4y ago
        It doesn't seem unfathomable that it could be the case that most advanced civs escape the confines of our limited universe or even evolved outside of it. Considering how many species there are, millions, it seems unlikely that we are at the "top" of the tree of life, but rather that we are unable to detect more advanced "animals" that are part of it.
  - est31 4y ago
    Assuming 0.1c travel, the galaxy can be covered in a million years already, which is way less than the lifetime of many species here on earth. But if you extend your argument to intergalactic travel, then you definitely have to start talking about billions of years. I generally think that this argument is the best one that FTL travel is impossible, because it would have increased the likelihood of non-human intelligent life close but outside of earth dramatically. Outside of course physics of the last 160 years being built on the fact that C is the fastest speed there is.
  - chimprich 4y ago
    > Either life is virtually non-existent thus far, virtually always suicidal, or discovering it is tremendously unlikely. Or they tend to sublime [0], or advanced societies prefer to live in virtual reality, or they tend towards being enlightened enough not to mess with species in an earlier stage of development, or they're not very interested in us, or we've been unlucky/lucky to have avoided discovery so far, or FTL is possible but can only be exceeded slightly, or FTL is possible but requires billions of years of technological development to achieve, or FTL requires a prohibitive amount of energy to travel at longer distances, etc., etc. [0] https://theculture.fandom.com/wiki/The_Sublimed https://theculture.fandom.com/wiki/The_Sublimed
- Aperocky 4y ago
  the physics were the same 5000 years ago, the people just didn't know it yet. Everything we've built so far, obeyed physics, and I expect that to remain true in perpetuity.
  - lostmsu 4y ago
    There are already highly theoretical schemes for FTL travel. For example, https://en.m.wikipedia.org/wiki/Alcubierre_drive https://en.m.wikipedia.org/wiki/Alcubierre_drive
    - _ZeD_ 4y ago
      I would call them "science fiction", but whatever
      - shepherdjerred 4y ago
        Think of everything we’ve discovered even in just the last 50 years, and how impossible it seemed from the perspective of the past. You can always argue that we know more now, that there are fundamental limits, etc., but there’s always more to learn and revise.
        tsimionescu 4y ago
        Nothing we've discovered in the last 50 years seemed impossible from the perspective of the past. They did seem much farther away, and some had just not been thought of, but no one in the 1970s would be completely incredulous at anything that exists today. Instead, many things that seemed possible 50-150 years ago have turned out in the meantime to be impossible - speeds faster than c (before Maxwell's equations and SR), arbitrary precision measurements (before Heisenberg's uncertainty principle), uniquely determining the future state of a system based on a previous state (before wave functions), arbitrary amounts of matter and energy (before quantization of these and other properties) etc. The history of physics is usually one of discovering new constraints, not one of discovering new possibilities. Before physics, we used to believe in unconstrained magic. Not only have we always believed we can reach the stars, we used to believe we could do it by finding the right magical formula or praying hard enough. Of course there are some exceptions - electricity and quantum computing come to mind.
kmarc 4y ago
What if we don't want to travel faster than light, just warp space around us (Sorry, I finished the third book of the Three Body Problem series literally an hour ago, and, well, curvature propulsion [1]) [1]: https://www.reddit.com/r/threebodyproblem/comments/6lj9df/can_anyone_explain_how_curvature_propulsion_works/ https://www.reddit.com/r/threebodyproblem/comments/6lj9df/ca...
sidkshatriya 4y ago
[Caution: vague speculation follows] Apparently exotic objects like wormholes may exist which can "teleport" one from one part of the universe to another while never violating the faster than light principle. [See https://en.wikipedia.org/wiki/Wormhole https://en.wikipedia.org/wiki/Wormhole ] In other words, we could have intergalactic messages. Our understanding of Physics is still evolving and things considered impossible today may become possible tomorrow without necessarily bringing the whole edifice of Physics down by taking paths that are not known so far. Grand as the achievements of modern Physics, we should still remain humble about what is possible and impossible.
- immmmmm 4y ago
  it's not easy keeping a wormhole open, while they are correct solutions to the General Relativity equation, they are widely unstable, if memory serves. also gravity is very weak and need a significant amount of mass/energy to source it, a black hole of the mass of the earth is a centimeter in diameter. and yes smaller black holes are in theory possible to make (in some theories at least) but they tend to evaporate very very quickly by hawking radiation (and none was observed at cern). then there's the ER=EPR conjecture that quantum entanglement is due to microscopic wormholes connecting the states but again doesn't seem you can shove a photon in there and get super luminal communication as quantum entanglement cannot transfer information faster than light. in the end Lorentz invariance and thus the speed of light is deeply embedded in the fabric of spacetime (we never seen any violations, and i saw the super luminal neutrino drama first hand as i was doing my phd in Bern) they are a bit like warp drives, possible in some theory, wildly impractical, certainly lethal and requires infinite energy and/or destroys the arrival galaxy. more realistically speaking, and i know ppl will hate me for this: we have a decline in biodiversity probably unprecedented since the dinosaurs went exciting, a near vertical climate trip to tackle (not making the first even worst), limited ressources to that mitigate it but more importantly: very few people paying attention. at this rate(s) i doubt the successor to the Large Hadron Collider will be ready before collapse of our civilization. i get it's nice to dream but we are tripping all regulation mechanisms on this planet and that's not something that's good for survival, fossil records show. maybe im wrong, im a physicist after all, and SuperElon FromTheFuture will ride a closed timelike curve and come Save Us All (TM) with electric rockets and SmartTechnology (C). (edit: added a pinch of dark humor.)

We're not going to be intergalactic by year 7298 for the simple fact that the Milky Way is 100000 light years across and traveling faster than light is physically forbidden

colordrops 4y ago

You really think our model of reality and what is possible will apply in 5,276 years? What did we understand 5,276 years ago? Most certainly countless things that we have now would be considered impossible or witchcraft back then.

michaelmrose 4y ago
If faster than light travel was possible any single species who discovered it would be able to cover an appreciable portion of the galaxy in only a few thousand years out of billions. Either life is virtually non-existent thus far, virtually always suicidal, or discovering it is tremendously unlikely. Neither of the last two bode well for us. It seems to me most likely that ftl suggestions an empty universe or one in which we too are likely to die without learning it.
- shepherdjerred 4y ago
  You’re assuming that all species seek to grow infinitely. What’s wrong with a species of sentient house cats that just want to nap all day?
  - geertj 4y ago
    > What’s wrong with a species of sentient house cats that just want to nap all day? Nothing wrong with that, but if life is common, you’d need all life to be like that to explain the Fermi paradox, which seems unlikely.
    - colordrops 4y ago
      It could also be that the technology to achieve FTL is just over a threshold where the civilization would be unrecognizable to us as humans. We aren't far from such technology already. For instance imagine just a few generations of biotech and computational technology - it may already be enough for us to transform and evolve into some biomechanical hive that bears little resemblance to our current selves. It could also be that once you are advanced enough, you transcend this physical universe. For example, the entire universe to a deep sea squid is cold dark water without much other life. They have no way to comprehend that there is so much more to reality. They just aren't capable of it. We are not special and also likely not able to detect or comprehend other levels of reality that would be more vast and interesting to advanced beings than simple FTL leaps around the galaxy. Perhaps they just aren't interested in our little ant hill the milky way. The lack of imagination around what is possible and the supposed paradox posited by Fermi is disheartening.
      - geertj 4y ago
        > The lack of imagination around what is possible and the supposed paradox posited by Fermi is disheartening. I think similar reasoning could apply though. If advanced civilizations escape into a different dimension or state of being where they are undetectable, we’d need all of them to do that to explain the Fermi paradox.
        michaelmrose 4y ago
        Exactly. Life being rare and spread out, space requiring enormous resources to move between stars, most species never outgrowing their backyards seems like it could credibly explain the paradox without FTL.
        colordrops 4y ago
        It doesn't seem unfathomable that it could be the case that most advanced civs escape the confines of our limited universe or even evolved outside of it. Considering how many species there are, millions, it seems unlikely that we are at the "top" of the tree of life, but rather that we are unable to detect more advanced "animals" that are part of it.
- est31 4y ago
  Assuming 0.1c travel, the galaxy can be covered in a million years already, which is way less than the lifetime of many species here on earth. But if you extend your argument to intergalactic travel, then you definitely have to start talking about billions of years. I generally think that this argument is the best one that FTL travel is impossible, because it would have increased the likelihood of non-human intelligent life close but outside of earth dramatically. Outside of course physics of the last 160 years being built on the fact that C is the fastest speed there is.
- chimprich 4y ago
  > Either life is virtually non-existent thus far, virtually always suicidal, or discovering it is tremendously unlikely. Or they tend to sublime [0], or advanced societies prefer to live in virtual reality, or they tend towards being enlightened enough not to mess with species in an earlier stage of development, or they're not very interested in us, or we've been unlucky/lucky to have avoided discovery so far, or FTL is possible but can only be exceeded slightly, or FTL is possible but requires billions of years of technological development to achieve, or FTL requires a prohibitive amount of energy to travel at longer distances, etc., etc. [0] https://theculture.fandom.com/wiki/The_Sublimed https://theculture.fandom.com/wiki/The_Sublimed
Aperocky 4y ago
the physics were the same 5000 years ago, the people just didn't know it yet. Everything we've built so far, obeyed physics, and I expect that to remain true in perpetuity.
- lostmsu 4y ago
  There are already highly theoretical schemes for FTL travel. For example, https://en.m.wikipedia.org/wiki/Alcubierre_drive https://en.m.wikipedia.org/wiki/Alcubierre_drive
  - _ZeD_ 4y ago
    I would call them "science fiction", but whatever
    - shepherdjerred 4y ago
      Think of everything we’ve discovered even in just the last 50 years, and how impossible it seemed from the perspective of the past. You can always argue that we know more now, that there are fundamental limits, etc., but there’s always more to learn and revise.
      - tsimionescu 4y ago
        Nothing we've discovered in the last 50 years seemed impossible from the perspective of the past. They did seem much farther away, and some had just not been thought of, but no one in the 1970s would be completely incredulous at anything that exists today. Instead, many things that seemed possible 50-150 years ago have turned out in the meantime to be impossible - speeds faster than c (before Maxwell's equations and SR), arbitrary precision measurements (before Heisenberg's uncertainty principle), uniquely determining the future state of a system based on a previous state (before wave functions), arbitrary amounts of matter and energy (before quantization of these and other properties) etc. The history of physics is usually one of discovering new constraints, not one of discovering new possibilities. Before physics, we used to believe in unconstrained magic. Not only have we always believed we can reach the stars, we used to believe we could do it by finding the right magical formula or praying hard enough. Of course there are some exceptions - electricity and quantum computing come to mind.

kmarc 4y ago

What if we don't want to travel faster than light, just warp space around us (Sorry, I finished the third book of the Three Body Problem series literally an hour ago, and, well, curvature propulsion [1]) [1]: https://www.reddit.com/r/threebodyproblem/comments/6lj9df/can_anyone_explain_how_curvature_propulsion_works/ https://www.reddit.com/r/threebodyproblem/comments/6lj9df/ca...

sidkshatriya 4y ago

[Caution: vague speculation follows] Apparently exotic objects like wormholes may exist which can "teleport" one from one part of the universe to another while never violating the faster than light principle. [See https://en.wikipedia.org/wiki/Wormhole https://en.wikipedia.org/wiki/Wormhole ] In other words, we could have intergalactic messages. Our understanding of Physics is still evolving and things considered impossible today may become possible tomorrow without necessarily bringing the whole edifice of Physics down by taking paths that are not known so far. Grand as the achievements of modern Physics, we should still remain humble about what is possible and impossible.

immmmmm 4y ago
it's not easy keeping a wormhole open, while they are correct solutions to the General Relativity equation, they are widely unstable, if memory serves. also gravity is very weak and need a significant amount of mass/energy to source it, a black hole of the mass of the earth is a centimeter in diameter. and yes smaller black holes are in theory possible to make (in some theories at least) but they tend to evaporate very very quickly by hawking radiation (and none was observed at cern). then there's the ER=EPR conjecture that quantum entanglement is due to microscopic wormholes connecting the states but again doesn't seem you can shove a photon in there and get super luminal communication as quantum entanglement cannot transfer information faster than light. in the end Lorentz invariance and thus the speed of light is deeply embedded in the fabric of spacetime (we never seen any violations, and i saw the super luminal neutrino drama first hand as i was doing my phd in Bern) they are a bit like warp drives, possible in some theory, wildly impractical, certainly lethal and requires infinite energy and/or destroys the arrival galaxy. more realistically speaking, and i know ppl will hate me for this: we have a decline in biodiversity probably unprecedented since the dinosaurs went exciting, a near vertical climate trip to tackle (not making the first even worst), limited ressources to that mitigate it but more importantly: very few people paying attention. at this rate(s) i doubt the successor to the Large Hadron Collider will be ready before collapse of our civilization. i get it's nice to dream but we are tripping all regulation mechanisms on this planet and that's not something that's good for survival, fossil records show. maybe im wrong, im a physicist after all, and SuperElon FromTheFuture will ride a closed timelike curve and come Save Us All (TM) with electric rockets and SmartTechnology (C). (edit: added a pinch of dark humor.)