5 ms·

Definitely not a stupid question, just the wrong question IMO. The real question would be do we have any reason to believe that they do still use radio? We've

Definitely not a stupid question, just the wrong question IMO. The real question would be do we have any reason to believe that they do still use radio? We've had radio for just a little over 200 years and we've already realized its limitations. The fact that we can even speculate about quantum communication leads me to believe that radio is definitely NOT the end-all-be-all. If you scale human civilization into a 1 year time frame we invent radio at 3PM on December 31st. It's successor likely emerges January 2nd at the latest. Radio communication is likely a blip. Radio is efficient over short terrestrial distance but horrible for long (galaxy scale) distance communication. If interstellar travel is feasible at all it will have to be at FTL speeds and an FTL communication system would be necessary. If FTL is truly impossible then it doesn't seem like there is much point in listening since everything is so incredibly far it's irrelevant even on a species-level or planetary-level time scale. I believe that everyone at SETI must believe FTL is possible because otherwise it truly is a waste of resources.

hannasanarion 8y ago
> The fact that we can even speculate about quantum communication leads me to believe that radio is definitely NOT the end-all-be-all Who is it that's speculating about quantum communication? Certainly not physicists. It's mostly just IFLScience!-class journalists seeing a term like "quantum teleportation" and assuming that it means start trek is real and write their articles based on that. > I believe that everyone at SETI must believe FTL is possible because otherwise it truly is a waste of resources. If everyone at SETI believes that mysterious FTL communication exists, then why do they spend all their time looking for EM signals?
- themagician 8y ago
  Because that's what we have today, so that's what they have to work with. It's a shot in the dark in the hope that we might be able to find a remnant sign. If we detect radio signals in another galaxy but FTL is impossible who cares? The human species will be extinct before any interaction can occur. It's probable that whatever species sent them is already extinct because it's at least 3 billion years old. If c is the ultimate speed limit there's really no point in looking anywhere else because everything else is so far away it's irrelevant.
  - int_19h 8y ago
    Knowledge doesn't need to have a practical purpose to be satisfying.
  - canhascodez 8y ago
    The problem is that you can either have FTL or causality, but not both. Also, relativity has been extremely accurate as a description of the universe, particularly on the macro level that you and I happen to inhabit. I'd say that I'd never bet on FTL being real, but to be honest I'd be surprised if you ever found anyone to even lay you odds. And as you say, that does make SETI rather pointless even without considering that the SNR to Mars on a good day is, what, ~11 dB? We get generation ships, and if we are extremely lucky, we may have some very patient pen-pals, but warp drives, ansibles, and their attendant paradoxes are pretty unlikely to be features of this universe. Personally I prefer a knowable universe to a tourable one.
  - hannasanarion 8y ago
    So you're saying we should shut down all of the large and Radio and space telescopes, because it's pointless to look at things you can't visit?
    - themagician 8y ago
      Not just visit, anything. You'd never be able to communicate. The SNR is such that it would always just be noise. If FTL isn't possible then the end result of listening is simply the confirmation that something else exists and it stops right there.
      - hannasanarion 8y ago
        Conversation isn't the only thing you can do with messages. Alan Turing didn't crack Enigma so that he could have a lovely chat with the Germans. Don't you think there's at least a little bit that could be learned by listening to alien communications from centuries ago, other than the fact that it exists? If such signals were found, would you really stop reading at the headline "alien communication discovered"?
tcgv 8y ago
>"If interstellar travel is feasible at all it will have to be at FTL speed" Why is that? Special relativity already demonstrates that space contraction at near light speed would allow interstellar travel at human scale duration, with the side effect of time dilation for moving observers. See: https://en.m.wikipedia.org/wiki/Twin_paradox https://en.m.wikipedia.org/wiki/Twin_paradox
- GW150914 8y ago
  Why would you bother taking a trip that involved leaving your entire species hundreds of thousands, even millions of years behind you? It would be energetically expensive, and the civilization that launched it couldn’t expect to care or remember by the time it arrived. That might work for a small group of pioneers willing to go into the blackness, but it’s not the basis for a galactic civilization.
  - tcgv 8y ago
    Even though it May not seem logical, the point is that interstellar travel without FTL speed is feasible.
    - GW150914 8y ago
      Its possible, but not at all feasible. It’s also not really practical and the nature of it undercuts the usual “where are all of the intelligent species colonizing the galaxy?” arguments which tend to crop up.
nearbuy 8y ago
> I believe that everyone at SETI must believe FTL is possible because otherwise it truly is a waste of resources. Isn't this like saying every historian must believe in time travel? Just because you can't visit someone doesn't mean you can't learn from them.
caf 8y ago
If FTL is truly impossible then it doesn't seem like there is much point in listening since everything is so incredibly far it's irrelevant even on a species-level or planetary-level time scale. Probably true on a species level, but you are vastly underestimating how long a planetary-level timescale is. A von Neumann probe could cover the entire Milky Way in relatively short geological time.

hannasanarion 8y ago

> The fact that we can even speculate about quantum communication leads me to believe that radio is definitely NOT the end-all-be-all Who is it that's speculating about quantum communication? Certainly not physicists. It's mostly just IFLScience!-class journalists seeing a term like "quantum teleportation" and assuming that it means start trek is real and write their articles based on that. > I believe that everyone at SETI must believe FTL is possible because otherwise it truly is a waste of resources. If everyone at SETI believes that mysterious FTL communication exists, then why do they spend all their time looking for EM signals?

themagician 8y ago
Because that's what we have today, so that's what they have to work with. It's a shot in the dark in the hope that we might be able to find a remnant sign. If we detect radio signals in another galaxy but FTL is impossible who cares? The human species will be extinct before any interaction can occur. It's probable that whatever species sent them is already extinct because it's at least 3 billion years old. If c is the ultimate speed limit there's really no point in looking anywhere else because everything else is so far away it's irrelevant.
- int_19h 8y ago
  Knowledge doesn't need to have a practical purpose to be satisfying.
- canhascodez 8y ago
  The problem is that you can either have FTL or causality, but not both. Also, relativity has been extremely accurate as a description of the universe, particularly on the macro level that you and I happen to inhabit. I'd say that I'd never bet on FTL being real, but to be honest I'd be surprised if you ever found anyone to even lay you odds. And as you say, that does make SETI rather pointless even without considering that the SNR to Mars on a good day is, what, ~11 dB? We get generation ships, and if we are extremely lucky, we may have some very patient pen-pals, but warp drives, ansibles, and their attendant paradoxes are pretty unlikely to be features of this universe. Personally I prefer a knowable universe to a tourable one.
- hannasanarion 8y ago
  So you're saying we should shut down all of the large and Radio and space telescopes, because it's pointless to look at things you can't visit?
  - themagician 8y ago
    Not just visit, anything. You'd never be able to communicate. The SNR is such that it would always just be noise. If FTL isn't possible then the end result of listening is simply the confirmation that something else exists and it stops right there.
    - hannasanarion 8y ago
      Conversation isn't the only thing you can do with messages. Alan Turing didn't crack Enigma so that he could have a lovely chat with the Germans. Don't you think there's at least a little bit that could be learned by listening to alien communications from centuries ago, other than the fact that it exists? If such signals were found, would you really stop reading at the headline "alien communication discovered"?

tcgv 8y ago

>"If interstellar travel is feasible at all it will have to be at FTL speed" Why is that? Special relativity already demonstrates that space contraction at near light speed would allow interstellar travel at human scale duration, with the side effect of time dilation for moving observers. See: https://en.m.wikipedia.org/wiki/Twin_paradox https://en.m.wikipedia.org/wiki/Twin_paradox

GW150914 8y ago
Why would you bother taking a trip that involved leaving your entire species hundreds of thousands, even millions of years behind you? It would be energetically expensive, and the civilization that launched it couldn’t expect to care or remember by the time it arrived. That might work for a small group of pioneers willing to go into the blackness, but it’s not the basis for a galactic civilization.
- tcgv 8y ago
  Even though it May not seem logical, the point is that interstellar travel without FTL speed is feasible.
  - GW150914 8y ago
    Its possible, but not at all feasible. It’s also not really practical and the nature of it undercuts the usual “where are all of the intelligent species colonizing the galaxy?” arguments which tend to crop up.

nearbuy 8y ago

> I believe that everyone at SETI must believe FTL is possible because otherwise it truly is a waste of resources. Isn't this like saying every historian must believe in time travel? Just because you can't visit someone doesn't mean you can't learn from them.

caf 8y ago

If FTL is truly impossible then it doesn't seem like there is much point in listening since everything is so incredibly far it's irrelevant even on a species-level or planetary-level time scale. Probably true on a species level, but you are vastly underestimating how long a planetary-level timescale is. A von Neumann probe could cover the entire Milky Way in relatively short geological time.