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Would a sufficiently advanced civilization really settle for communication that crawls at the speed of light though? And before you say "anything faster than l

Would a sufficiently advanced civilization really settle for communication that crawls at the speed of light though? And before you say "anything faster than light is impossible": it's impossible according to our current understanding of physics. How much that understanding aligns with reality, especially with relation to quantum mechanics, is debatable.

krapp 5y ago
Until there's actual evidence to the contrary, the "debate" is one side with all of the science and the other side waving around a Star Trek technical manual.
- grishka 5y ago
  History knows multiple examples when people had a theory about something and it agreed with their observations, but then they observed a discrepancy, and then another one, and tried to rectify them by adding more and more rather arbitrary conditions or exceptions to their theory. Until it was proven completely wrong and a much better, and much simpler, explanation was found. One example is this "phlogiston theory"[1] describing how and why things burn before we knew about atoms and molecules. It did its job and explained people's observations about the process of combustion. But then it was found out that for some substances, their weight increases after they've been burnt. This was explained by phlogiston having negative weight... sometimes. Or being lighter than air, also sometimes. Another one is how we first thought that the universe revolves around the earth. And then we had complex formulas that described the motion of celestial bodies as we see them on the sky. And guess what? It turned out to be much simpler than we thought. And then our current theories can't explain redshift, so we assume that the universe must be expanding. And they can't explain how outer parts of galaxies spin faster than they should be spinning, so we invent dark matter to reconcile that. See a pattern? [1] https://en.wikipedia.org/wiki/Phlogiston_theory https://en.wikipedia.org/wiki/Phlogiston_theory
  - krapp 5y ago
    The pattern I see is one of constant refinement as technology and prior knowledge allows for more effective experimentation, greater observations, and physical models which increase in accuracy over time, despite still being incomplete. General and special relativity are the most thoroughly tested and confirmed models ever to have existed to date [0,1]. And while it is currently not possible to reconcile quantum mechanics and general relativity, quantum mechanics was reconciled with special relativity by Dirac in 1928, and the light speed limit on the transmission of information remains. And there are no observations which suggest a flaw in current models akin to redshift or the orbit of Mercury which suggest the light speed limit is incorrect, rather, experiment has always validated it[2]. We now know that even the speed of gravity itself is limited to the speed of light[3]. It seems as if you're confident that any day now we'll discover that relativity was just as wrong as alchemy and phlogiston all along, and that there's some simple and elegant truth everyone missed that somehow both describes the universe more accurately than current models and also just happens to allow for arbitrary FTL communication and travel. We'll have to agree to disagree. [0]https://en.wikipedia.org/wiki/Tests_of_general_relativity https://en.wikipedia.org/wiki/Tests_of_general_relativity [1]https://en.wikipedia.org/wiki/Tests_of_special_relativity https://en.wikipedia.org/wiki/Tests_of_special_relativity [2]https://en.wikipedia.org/wiki/Speed_of_light https://en.wikipedia.org/wiki/Speed_of_light [3]https://en.wikipedia.org/wiki/Speed_of_gravity https://en.wikipedia.org/wiki/Speed_of_gravity
    - grishka 5y ago
      > It seems as if you're confident that any day now we'll discover that relativity was just as wrong as alchemy and phlogiston all along I'm not saying that relativity is wrong. It's correct because it clearly aligns with our observations and predicts many things. But here's the problem: we don't know what space and time are, in the physical sense. We don't know what they're made of. We don't know how malleable they are. It might well be the case that relativity is just one of the parts of a bigger "theory of everything" that does in fact allow FTL travel and/or communication. There were links to papers here on HN how a warp drive is possible without breaking relativity, by making space "flow around" a bubble containing your spaceship instead of propelling the ship itself. Relativity also doesn't forbid almost-Stargate-style traversable wormholes — we just don't know how to make one and most probably don't have enough energy even if we did.

krapp 5y ago

Until there's actual evidence to the contrary, the "debate" is one side with all of the science and the other side waving around a Star Trek technical manual.

grishka 5y ago
History knows multiple examples when people had a theory about something and it agreed with their observations, but then they observed a discrepancy, and then another one, and tried to rectify them by adding more and more rather arbitrary conditions or exceptions to their theory. Until it was proven completely wrong and a much better, and much simpler, explanation was found. One example is this "phlogiston theory"[1] describing how and why things burn before we knew about atoms and molecules. It did its job and explained people's observations about the process of combustion. But then it was found out that for some substances, their weight increases after they've been burnt. This was explained by phlogiston having negative weight... sometimes. Or being lighter than air, also sometimes. Another one is how we first thought that the universe revolves around the earth. And then we had complex formulas that described the motion of celestial bodies as we see them on the sky. And guess what? It turned out to be much simpler than we thought. And then our current theories can't explain redshift, so we assume that the universe must be expanding. And they can't explain how outer parts of galaxies spin faster than they should be spinning, so we invent dark matter to reconcile that. See a pattern? [1] https://en.wikipedia.org/wiki/Phlogiston_theory https://en.wikipedia.org/wiki/Phlogiston_theory
- krapp 5y ago
  The pattern I see is one of constant refinement as technology and prior knowledge allows for more effective experimentation, greater observations, and physical models which increase in accuracy over time, despite still being incomplete. General and special relativity are the most thoroughly tested and confirmed models ever to have existed to date [0,1]. And while it is currently not possible to reconcile quantum mechanics and general relativity, quantum mechanics was reconciled with special relativity by Dirac in 1928, and the light speed limit on the transmission of information remains. And there are no observations which suggest a flaw in current models akin to redshift or the orbit of Mercury which suggest the light speed limit is incorrect, rather, experiment has always validated it[2]. We now know that even the speed of gravity itself is limited to the speed of light[3]. It seems as if you're confident that any day now we'll discover that relativity was just as wrong as alchemy and phlogiston all along, and that there's some simple and elegant truth everyone missed that somehow both describes the universe more accurately than current models and also just happens to allow for arbitrary FTL communication and travel. We'll have to agree to disagree. [0]https://en.wikipedia.org/wiki/Tests_of_general_relativity https://en.wikipedia.org/wiki/Tests_of_general_relativity [1]https://en.wikipedia.org/wiki/Tests_of_special_relativity https://en.wikipedia.org/wiki/Tests_of_special_relativity [2]https://en.wikipedia.org/wiki/Speed_of_light https://en.wikipedia.org/wiki/Speed_of_light [3]https://en.wikipedia.org/wiki/Speed_of_gravity https://en.wikipedia.org/wiki/Speed_of_gravity
  - grishka 5y ago
    > It seems as if you're confident that any day now we'll discover that relativity was just as wrong as alchemy and phlogiston all along I'm not saying that relativity is wrong. It's correct because it clearly aligns with our observations and predicts many things. But here's the problem: we don't know what space and time are, in the physical sense. We don't know what they're made of. We don't know how malleable they are. It might well be the case that relativity is just one of the parts of a bigger "theory of everything" that does in fact allow FTL travel and/or communication. There were links to papers here on HN how a warp drive is possible without breaking relativity, by making space "flow around" a bubble containing your spaceship instead of propelling the ship itself. Relativity also doesn't forbid almost-Stargate-style traversable wormholes — we just don't know how to make one and most probably don't have enough energy even if we did.