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I did used to entertain the idea of aliens visiting this solar system. And then I better understood the stupendous energy requirements for a two-way trip to ev

I did used to entertain the idea of aliens visiting this solar system. And then I better understood the stupendous energy requirements for a two-way trip to even the very closest neighboring solar system. And it is just not practical, even for a civilization at the end of the technology development tree. We might see one-way probes, but they are as likely to be a part of hegemonizing swarm, looking to convert all usable matter in the solar system into computronium. Certainly they're not going to just faff around, kidnap a few people and then leave quietly. When aliens visit, everyone will know. Luckily, we haven't seen any evidence of Kardashev type-2 civilizations nearby, so we may be good for a while. Though that's also sort of depressing, as it is weak evidence that life is not too common across the galaxy.

jordwest 6y ago
> even for a civilization at the end of the technology development tree. How do we know what the end of the technology development tree looks like? There are just so many mysteries that remain within our current understanding of science, we can’t say for sure that it’s not easy (for example) to bend space time or some other possibility that makes faster than light travel possible. Quantum entanglement, for example, breaks many of our assumptions about the impossibility of FTL travel. > When aliens visit, everyone will know. Maybe, but perhaps a civilisation that has survived the great filter would look differently at civilisations they stumble upon. Maybe, like we do when searching for microbes on Mars, they would try not to disturb the life they discover. This is all just speculation of course, but I think when looking at this topic it’s all too easy to apply a human centric view on what’s possible and what’s not, and the truth is we just know so very little. Or, we know a lot, but there are so many more mysteries than solved problems.
- dplavery92 6y ago
  While I would also not presume to know how different our understanding of the universe may look in hundreds (or thousands!) of years, I do draw some exception to the following comment: >Quantum entanglement, for example, breaks many of our assumptions about the impossibility of FTL travel. Quantum entanglement can produce correlated measurements between systems, even when the entangled systems are separated by large distances. In a sense, this can be used to measure the state of an entangled system at great displacement "faster" than it would take light to travel from that distant system to the observer. However, the state of the entangled systems is prepared before the systems are separated from one another (at much less than the speed of light.) Any attempt to change the state of one of the entangled systems (at a distance) breaks the entanglement. Entanglement cannot be used to communicate information from one point to another faster than the speed of light. It certainly doesn't allow FTL transfer of matter/energy.
  - jordwest 6y ago
    > However, the state of the entangled systems is prepared before the systems are separated from one another Isn’t the state still a probabilistic one at that point though? As in it’s not until it’s observed later that both particles instantaneously collapse into a correlated state. But the precise outcome of the observation isn’t determined before they’re separated. My understanding of quantum mechanics is far too limited to really dive into this, but my point isn’t that it enables FTL communication or travel directly. Rather my understanding is that it appears to break our previous assumptions - physicists haven’t yet settled on a way to unify relativity and quantum physics [1] which leaves many possibilities open. We still just don’t know enough to say it’s definitely impossible. [1] https://en.m.wikipedia.org/wiki/Problem_of_time https://en.m.wikipedia.org/wiki/Problem_of_time
    - dplavery92 6y ago
      >Isn’t the state still a probabilistic one at that point though? As in it’s not until it’s observed later that both particles instantaneously collapse into a correlated state. But the precise outcome of the observation isn’t determined before they’re separated. This is correct.
  - withinboredom 6y ago
    I’ve never looked too deeply into this, but why can’t someone use something like Morse Code to communicate? Say you had 50 buckets of entangled entities, that would get you 50 dots and dashes.
    - dplavery92 6y ago
      Because if you attempt to influence the state of the entangled bits--say, to set a bit to up/down (dot/dash or zero/one) state to form your message--you will break the entanglement. You can measure the states of the unperturbed entangled bits, and therefore know about the states of their distant entangled partners, but the message will be random. You could also influence the states of the bits while you create the entangled pairs, but then you have to carry them far away from one another (at less than the speed of light), so you won't be able to communicate FTL; you would just have a pair of messages in a bottle, so to speak.
felixchan 6y ago
>And then I better understood the stupendous energy requirements for a two-way trip to even the very closest neighboring solar system. And it is just not practical, even for a civilization at the end of the technology development tree. This is blind arrogance.
- ansible 6y ago
  Eh, no it isn't arrogance. It is math and physics. Have a look at a few links. So first off, chemical propulsion is right out: https://blogs.scientificamerican.com/life-unbounded/why-chemical-rockets-and-interstellar-travel-dont-mix/ https://blogs.scientificamerican.com/life-unbounded/why-chem... You really need something like anti-matter: https://en.wikipedia.org/wiki/Interstellar_travel https://en.wikipedia.org/wiki/Interstellar_travel You're still looking at hundreds of years or more for a nearby two-way trip. It is far more practical to send out probes one-way (which is quite slow), and then build the infrastructure at the destination to receive transmitted mind-states. The initial probes take a long time to reach their destinations, because they have to have means to deaccelerate. The faster you accelerate, the more mass you have to carry with you to deaccelerate.
  - felixchan 6y ago
    It's arrogance because you think that your current system of science is relevant. Civilization has been around for only 5000 years. How do you know other planets do not have elements that have anti-matter properties?
    - ansible 6y ago
      > It's arrogance because you think that your current system of science is relevant. Civilization has been around for only 5000 years. So, if magic exists, there also might be aliens. Got it. > How do you know other planets do not have elements that have anti-matter properties? Well, we haven't observed anything that gives even a hint that something like that exists. The matter / antimatter disparity is still quite a mystery. But we don't see any evidence of antimatter out there in any significant quantities. So if aliens want to use it, they have to make it the hard way, just like we do. Beyond current state-of-the-art technology would make manufacturing and containment of antimatter easier, but even then it is a long way from practical.
MicahKV 6y ago
I like to think that advanced alien life may already be established in our solar system, and we just haven't detected it yet. Unlikely as that is, the solar system is a big place and we are still just scratching the surface in terms of exploring it. Perhaps we have a highly advanced neighbor that values their privacy and has the technology to remain concealed from our "primitive" observation capabilities? Again, not likely but it's fun to think about.
sethammons 6y ago
> I did used to entertain the idea of communicating near instantly over great distances. > And then I better understood the stupendous energy requirements to shout/yell/make noise for a two-way round trip of sound waves from one county to the very closest neighboring county. And it is just not practical, even for a civilization at he end of the technology development tree (as known to us 1k years ago). If we were to look at communicating via radio waves with the technology of the ancient Greeks, they might wonder how we could possibly shout loud enough to be heard so far away. And why, if visits from another world were possible, would everyone know? If I found myself in ancient Greece and talked over a walkie talkie, it would be the same as something with crazy advanced travel technology just stopping by on their safari trip through our solar system.

jordwest 6y ago

> even for a civilization at the end of the technology development tree. How do we know what the end of the technology development tree looks like? There are just so many mysteries that remain within our current understanding of science, we can’t say for sure that it’s not easy (for example) to bend space time or some other possibility that makes faster than light travel possible. Quantum entanglement, for example, breaks many of our assumptions about the impossibility of FTL travel. > When aliens visit, everyone will know. Maybe, but perhaps a civilisation that has survived the great filter would look differently at civilisations they stumble upon. Maybe, like we do when searching for microbes on Mars, they would try not to disturb the life they discover. This is all just speculation of course, but I think when looking at this topic it’s all too easy to apply a human centric view on what’s possible and what’s not, and the truth is we just know so very little. Or, we know a lot, but there are so many more mysteries than solved problems.

dplavery92 6y ago
While I would also not presume to know how different our understanding of the universe may look in hundreds (or thousands!) of years, I do draw some exception to the following comment: >Quantum entanglement, for example, breaks many of our assumptions about the impossibility of FTL travel. Quantum entanglement can produce correlated measurements between systems, even when the entangled systems are separated by large distances. In a sense, this can be used to measure the state of an entangled system at great displacement "faster" than it would take light to travel from that distant system to the observer. However, the state of the entangled systems is prepared before the systems are separated from one another (at much less than the speed of light.) Any attempt to change the state of one of the entangled systems (at a distance) breaks the entanglement. Entanglement cannot be used to communicate information from one point to another faster than the speed of light. It certainly doesn't allow FTL transfer of matter/energy.
- jordwest 6y ago
  > However, the state of the entangled systems is prepared before the systems are separated from one another Isn’t the state still a probabilistic one at that point though? As in it’s not until it’s observed later that both particles instantaneously collapse into a correlated state. But the precise outcome of the observation isn’t determined before they’re separated. My understanding of quantum mechanics is far too limited to really dive into this, but my point isn’t that it enables FTL communication or travel directly. Rather my understanding is that it appears to break our previous assumptions - physicists haven’t yet settled on a way to unify relativity and quantum physics [1] which leaves many possibilities open. We still just don’t know enough to say it’s definitely impossible. [1] https://en.m.wikipedia.org/wiki/Problem_of_time https://en.m.wikipedia.org/wiki/Problem_of_time
  - dplavery92 6y ago
    >Isn’t the state still a probabilistic one at that point though? As in it’s not until it’s observed later that both particles instantaneously collapse into a correlated state. But the precise outcome of the observation isn’t determined before they’re separated. This is correct.
- withinboredom 6y ago
  I’ve never looked too deeply into this, but why can’t someone use something like Morse Code to communicate? Say you had 50 buckets of entangled entities, that would get you 50 dots and dashes.
  - dplavery92 6y ago
    Because if you attempt to influence the state of the entangled bits--say, to set a bit to up/down (dot/dash or zero/one) state to form your message--you will break the entanglement. You can measure the states of the unperturbed entangled bits, and therefore know about the states of their distant entangled partners, but the message will be random. You could also influence the states of the bits while you create the entangled pairs, but then you have to carry them far away from one another (at less than the speed of light), so you won't be able to communicate FTL; you would just have a pair of messages in a bottle, so to speak.

felixchan 6y ago

>And then I better understood the stupendous energy requirements for a two-way trip to even the very closest neighboring solar system. And it is just not practical, even for a civilization at the end of the technology development tree. This is blind arrogance.

ansible 6y ago
Eh, no it isn't arrogance. It is math and physics. Have a look at a few links. So first off, chemical propulsion is right out: https://blogs.scientificamerican.com/life-unbounded/why-chemical-rockets-and-interstellar-travel-dont-mix/ https://blogs.scientificamerican.com/life-unbounded/why-chem... You really need something like anti-matter: https://en.wikipedia.org/wiki/Interstellar_travel https://en.wikipedia.org/wiki/Interstellar_travel You're still looking at hundreds of years or more for a nearby two-way trip. It is far more practical to send out probes one-way (which is quite slow), and then build the infrastructure at the destination to receive transmitted mind-states. The initial probes take a long time to reach their destinations, because they have to have means to deaccelerate. The faster you accelerate, the more mass you have to carry with you to deaccelerate.
- felixchan 6y ago
  It's arrogance because you think that your current system of science is relevant. Civilization has been around for only 5000 years. How do you know other planets do not have elements that have anti-matter properties?
  - ansible 6y ago
    > It's arrogance because you think that your current system of science is relevant. Civilization has been around for only 5000 years. So, if magic exists, there also might be aliens. Got it. > How do you know other planets do not have elements that have anti-matter properties? Well, we haven't observed anything that gives even a hint that something like that exists. The matter / antimatter disparity is still quite a mystery. But we don't see any evidence of antimatter out there in any significant quantities. So if aliens want to use it, they have to make it the hard way, just like we do. Beyond current state-of-the-art technology would make manufacturing and containment of antimatter easier, but even then it is a long way from practical.

MicahKV 6y ago

I like to think that advanced alien life may already be established in our solar system, and we just haven't detected it yet. Unlikely as that is, the solar system is a big place and we are still just scratching the surface in terms of exploring it. Perhaps we have a highly advanced neighbor that values their privacy and has the technology to remain concealed from our "primitive" observation capabilities? Again, not likely but it's fun to think about.

sethammons 6y ago

> I did used to entertain the idea of communicating near instantly over great distances. > And then I better understood the stupendous energy requirements to shout/yell/make noise for a two-way round trip of sound waves from one county to the very closest neighboring county. And it is just not practical, even for a civilization at he end of the technology development tree (as known to us 1k years ago). If we were to look at communicating via radio waves with the technology of the ancient Greeks, they might wonder how we could possibly shout loud enough to be heard so far away. And why, if visits from another world were possible, would everyone know? If I found myself in ancient Greece and talked over a walkie talkie, it would be the same as something with crazy advanced travel technology just stopping by on their safari trip through our solar system.