3 ms·

To be fair, because we don't know how to construct gravity waves does not mean such a means does not exist. Keep in mind, not too long ago we thought we needed

To be fair, because we don't know how to construct gravity waves does not mean such a means does not exist. Keep in mind, not too long ago we thought we needed to heat up a fillament surrounded by an inert gas in order to make artificial light, and our understanding of gravity is fairly poor (to the point where it's largely considered an unsolved problem quite how it fits together with other parts of physics).

SketchySeaBeast 4y ago
If we make assumptions like that then the sky is the limit for other baseless assumptions, right? We're basically just picking our favourite pseudomagical science and arguing for it?
- marginalia_nu 4y ago
  Well that is the basic posture of all science, uncertainty. We must assume we don't know until we are convinced otherwise.
  - SketchySeaBeast 4y ago
    But you don't use that to suggest new unsupported ideas. In that case why can't I postulate for FTL communication by form of anti protons to be the best communication method?
    - marginalia_nu 4y ago
      I've never talked about FTL communication.
      - SketchySeaBeast 4y ago
        I didn't say you were. I was trying to make the point we're both suggesting science fiction now and it's not terribly helpful when trying to talk about the current science.
      - misnome 4y ago
        By your argument, shouldn’t we assume that it’s possible by <literally any means you can imagine> that we just don’t know about?
        marginalia_nu 4y ago
        Not necessarily. We have no reason to assume gravity waves couldn't be produced artificially. This wouldn't really break any existing understandings of physics, it would merely require adding to them. The question is just how. We do have reason to think that information can't travel faster than the speed of light, as this would make it possible to send information to the future and then back to the past via a closed time-like curve, which would have all manner of effects that contradict what we've observed about how the universe works, and in fact are self-contradictory as well. This doesn't go to say this isn't possible, after all the Alcubierre drive seems hypothetically possible (it "only" hinges upon the ability to create negative energy density), it's just much more implausible.
        misnome 4y ago
        But you don’t know that to be the case, so shouldn’t we assume it’s possible? It’s not the possibility of communication with gravity waves that people are disputing, it’s that without as much science fiction as FTL the energy requirements are so massive that you completely negate the arguments against light for the same purpose. Without this SF leap, you could just pour the energy into making a light as bright as e.g. a supernova and it would be multiple orders of magnitude cheaper and less difficult to generate the energy. This is completely ignoring the case where you know the direction you want to communicate with and build a laser. Yes, you can come up with plausible sounding SF ideas about why you might want to do this but please don’t pretend that it’s grounded in anything tangible.
- whycome 4y ago
  What assumption are you referring to? That it might be possible to use gravity waves as a form of communication?
  - SketchySeaBeast 4y ago
    > To be fair, because we don't know how to construct gravity waves does not mean such a means does not exist. The assumption that there's some way to use gravity waves easily.
jerf 4y ago
I believe it is important to separate flights of fancy from things grounded in real science, no matter how speculative. I can't prove that I can't generate gravity waves by the proper chanting of a spell. I'm serious, not just being silly. The simulation hypothesis certainly admits of such things being built into an otherwise sensible simulation (at the risk of a bit of a spoiler, https://qntm.org/ra https://qntm.org/ra ). If you want to talk about what could be if we bend what we understand this way, by all means, be my guest. I'm a big fan, actually. However, I think we should be clear that we are doing that, and specify the rule changes we're considering. In the real universe, we do "know" how to generate gravity waves. We can't do it at any sensible scale, but we know how. The energy computations are trivial extensions of Einsteinian relativity, suitable for assigning an undergraduate for homework. Besides, the way of making gravity waves has to not just be like three or four times better than wiggling a neutron star, to beat light, it needs to be the aforementioned dozens of orders of magnitude better. Just like lasers, you'd be looking at the thing being a great weapon rather than just a communication mechanism. It's actually a lot of orders of magnitude improvement necessary. A fire on the end of a stick versus the brightest modern stadium lights don't even begin to cover the magnitude range. People keep acting like light is some sort of terrible communication mechanism that we need to somehow level up from. The reality is that the only improvement you could practically ask of it is to go faster. It is otherwise unbelievably good at communication. It is hard to even conceive of what could be better in anything like our real universe.

SketchySeaBeast 4y ago

If we make assumptions like that then the sky is the limit for other baseless assumptions, right? We're basically just picking our favourite pseudomagical science and arguing for it?

marginalia_nu 4y ago
Well that is the basic posture of all science, uncertainty. We must assume we don't know until we are convinced otherwise.
- SketchySeaBeast 4y ago
  But you don't use that to suggest new unsupported ideas. In that case why can't I postulate for FTL communication by form of anti protons to be the best communication method?
  - marginalia_nu 4y ago
    I've never talked about FTL communication.
    - SketchySeaBeast 4y ago
      I didn't say you were. I was trying to make the point we're both suggesting science fiction now and it's not terribly helpful when trying to talk about the current science.
    - misnome 4y ago
      By your argument, shouldn’t we assume that it’s possible by <literally any means you can imagine> that we just don’t know about?
      - marginalia_nu 4y ago
        Not necessarily. We have no reason to assume gravity waves couldn't be produced artificially. This wouldn't really break any existing understandings of physics, it would merely require adding to them. The question is just how. We do have reason to think that information can't travel faster than the speed of light, as this would make it possible to send information to the future and then back to the past via a closed time-like curve, which would have all manner of effects that contradict what we've observed about how the universe works, and in fact are self-contradictory as well. This doesn't go to say this isn't possible, after all the Alcubierre drive seems hypothetically possible (it "only" hinges upon the ability to create negative energy density), it's just much more implausible.
        misnome 4y ago
        But you don’t know that to be the case, so shouldn’t we assume it’s possible? It’s not the possibility of communication with gravity waves that people are disputing, it’s that without as much science fiction as FTL the energy requirements are so massive that you completely negate the arguments against light for the same purpose. Without this SF leap, you could just pour the energy into making a light as bright as e.g. a supernova and it would be multiple orders of magnitude cheaper and less difficult to generate the energy. This is completely ignoring the case where you know the direction you want to communicate with and build a laser. Yes, you can come up with plausible sounding SF ideas about why you might want to do this but please don’t pretend that it’s grounded in anything tangible.
whycome 4y ago
What assumption are you referring to? That it might be possible to use gravity waves as a form of communication?
- SketchySeaBeast 4y ago
  > To be fair, because we don't know how to construct gravity waves does not mean such a means does not exist. The assumption that there's some way to use gravity waves easily.

jerf 4y ago

I believe it is important to separate flights of fancy from things grounded in real science, no matter how speculative. I can't prove that I can't generate gravity waves by the proper chanting of a spell. I'm serious, not just being silly. The simulation hypothesis certainly admits of such things being built into an otherwise sensible simulation (at the risk of a bit of a spoiler, https://qntm.org/ra https://qntm.org/ra ). If you want to talk about what could be if we bend what we understand this way, by all means, be my guest. I'm a big fan, actually. However, I think we should be clear that we are doing that, and specify the rule changes we're considering. In the real universe, we do "know" how to generate gravity waves. We can't do it at any sensible scale, but we know how. The energy computations are trivial extensions of Einsteinian relativity, suitable for assigning an undergraduate for homework. Besides, the way of making gravity waves has to not just be like three or four times better than wiggling a neutron star, to beat light, it needs to be the aforementioned dozens of orders of magnitude better. Just like lasers, you'd be looking at the thing being a great weapon rather than just a communication mechanism. It's actually a lot of orders of magnitude improvement necessary. A fire on the end of a stick versus the brightest modern stadium lights don't even begin to cover the magnitude range. People keep acting like light is some sort of terrible communication mechanism that we need to somehow level up from. The reality is that the only improvement you could practically ask of it is to go faster. It is otherwise unbelievably good at communication. It is hard to even conceive of what could be better in anything like our real universe.