4 ms·

"Life in other places might be radically different from our own, and we might be looking for the wrong things" Very possible. Something behind our imagination

"Life in other places might be radically different from our own, and we might be looking for the wrong things" Very possible. Something behind our imagination (e.g. Energy, Light based life forms etc.). But it is not unreasonable to expect something similar, based out of Carbon or Si that has a metabolism and senses. Once I read a suggestion to look for life: look for an entropy source.

thenobsta 3y ago
I always thought it would be a cool investigation to look at the distribution of entropy signals coming from celestial bodies and group them. I'd bet there is a non-'natural' entropic signal coming from planets with biological processes on them.
- breezeTrowel 3y ago
  How would you measure entropy signals at astronomical distances?
  - deleted 3y ago
    [deleted]
- PeterisP 3y ago
  It's interesting that both compression and encryption turn otherwise clearly "engineered" signals into something that's literally indistinguishable from noise, removing any redundancy or regularity.
  - giantrobot 3y ago
    The inverse square law means we're not going to pick up stray radio signals from an alien civilization. If you build an Arecibo-equivalent telescope (AET) in space and flew it out of the solar system our radio noise (uncompressed and unencrypted) would fade into the cosmic background at about half a light year out. Even powerful radars wouldn't be detectable much past Alpha Centauri assuming their beam even happens to sweep the portion of the sky where the receiver will be taking into account proper motion between the systems. The only way alien civilizations will pick up each others' signals is if they're intentionally directed at those systems with highly focused emitters. If you're intentionally sending a signal in hopes another civilization will see it you're definitely not going to encrypt it. Compression also serves little purpose as there's no shared context to decompress the message.
    - m4rtink 3y ago
      It should be possible to build much larger (and lighter!) radiotelescopes in the microgravity of space & whole arrays of them.
  - nonameiguess 3y ago
    Encryption can't hide the fact that there is a signal. Sufficiently secure encryption makes it so that any ciphertext you receive is equally likely to have been produced by any plaintext. But if you're able to observe that some ground station on Earth transmits radio to the same point in orbit, at the same time, every day, and receives a response, the fact that that is happening can defininitely be distinguished from any natural process. By the same token, if humanity disappeared but left a bunch of encrypted hard drives around and aliens came and found them, they may have no hope of distinguishing the bits from random bits, but they'd be able to tell that no natural process encodes any kind of bits at all onto magnetic discs or flash drives or whatever else we manage to come up with. The actual issue is what the other commenter said about the impossibility of detecting such low power radio at all.
    - kragen 3y ago
      you can observe that there is a radiation source, but if what it's emitting is nearly isotropic white noise, the most likely explanation is that it's just hot historical forms of signal modulation like ook and fm don't look very much like white noise, because they're designed to be demodulated by circuits with 1-10 vacuum tubes, but more modern modulations can look pretty white. they'd look a lot whiter if they weren't constrained by regulation to strongly attenuate bands used by obsolete forms of signal modulation
indigochill 3y ago
> look for an entropy source I think even this is a bit of an assumption. I have a sort of thought experiment that what we call physics and what our ancestors saw as angels or spirits moving the heavenly bodies _could_ actually both be true. Life as we know it is a source of entropy but if we take the view of God as an architect/clockmaker who created the universe as a (mostly?) deterministic machine with angels being his agents, it would stand to reason angels would be orderly as well rather than chaotic. Perhaps so orderly we would perceive their invisible involvement as natural laws rather than unusual miraculous intervention people usually expect from that sort of thing. Of course it's unprovable and even if you proved it it doesn't really contribute much to our understanding of the natural world, but it's interesting to imagine a form of life so orderly that we don't even perceive it as life but as part of the machinery of the universe.
- keep_reading 3y ago
  This hypothetical form of life -- what would its form of death look like? Where could we observe these dead angels / natural laws? If it can't die it's not alive
  - hnlmorg 3y ago
    Why is it not alive? None of our current definitions of life, limited as they might be, require death as measurement. And just because life on earth is fragile, it doesn’t mean all forms of life have to be.
    - keep_reading 3y ago
      Death has to be a measurement. If it can live it can die.
      - hnlmorg 3y ago
        You haven't answered my question as to why.
    - deleted 3y ago
dieselgate 3y ago
Yeah I agree with this. In practice "who knows?!" what it could look like! But in theory, given the precedence available, I think it'd likely be similar to what we know (carbon, metabolism, maybe crab-like).
deleted 3y ago
[deleted]
someotherperson 3y ago
Would light-based lightforms know they exist? Would they even have an existence? It feels like it would be over the moment it begins.

thenobsta 3y ago

I always thought it would be a cool investigation to look at the distribution of entropy signals coming from celestial bodies and group them. I'd bet there is a non-'natural' entropic signal coming from planets with biological processes on them.

breezeTrowel 3y ago
How would you measure entropy signals at astronomical distances?
- deleted 3y ago
  [deleted]
PeterisP 3y ago
It's interesting that both compression and encryption turn otherwise clearly "engineered" signals into something that's literally indistinguishable from noise, removing any redundancy or regularity.
- giantrobot 3y ago
  The inverse square law means we're not going to pick up stray radio signals from an alien civilization. If you build an Arecibo-equivalent telescope (AET) in space and flew it out of the solar system our radio noise (uncompressed and unencrypted) would fade into the cosmic background at about half a light year out. Even powerful radars wouldn't be detectable much past Alpha Centauri assuming their beam even happens to sweep the portion of the sky where the receiver will be taking into account proper motion between the systems. The only way alien civilizations will pick up each others' signals is if they're intentionally directed at those systems with highly focused emitters. If you're intentionally sending a signal in hopes another civilization will see it you're definitely not going to encrypt it. Compression also serves little purpose as there's no shared context to decompress the message.
  - m4rtink 3y ago
    It should be possible to build much larger (and lighter!) radiotelescopes in the microgravity of space & whole arrays of them.
- nonameiguess 3y ago
  Encryption can't hide the fact that there is a signal. Sufficiently secure encryption makes it so that any ciphertext you receive is equally likely to have been produced by any plaintext. But if you're able to observe that some ground station on Earth transmits radio to the same point in orbit, at the same time, every day, and receives a response, the fact that that is happening can defininitely be distinguished from any natural process. By the same token, if humanity disappeared but left a bunch of encrypted hard drives around and aliens came and found them, they may have no hope of distinguishing the bits from random bits, but they'd be able to tell that no natural process encodes any kind of bits at all onto magnetic discs or flash drives or whatever else we manage to come up with. The actual issue is what the other commenter said about the impossibility of detecting such low power radio at all.
  - kragen 3y ago
    you can observe that there is a radiation source, but if what it's emitting is nearly isotropic white noise, the most likely explanation is that it's just hot historical forms of signal modulation like ook and fm don't look very much like white noise, because they're designed to be demodulated by circuits with 1-10 vacuum tubes, but more modern modulations can look pretty white. they'd look a lot whiter if they weren't constrained by regulation to strongly attenuate bands used by obsolete forms of signal modulation

indigochill 3y ago

> look for an entropy source I think even this is a bit of an assumption. I have a sort of thought experiment that what we call physics and what our ancestors saw as angels or spirits moving the heavenly bodies _could_ actually both be true. Life as we know it is a source of entropy but if we take the view of God as an architect/clockmaker who created the universe as a (mostly?) deterministic machine with angels being his agents, it would stand to reason angels would be orderly as well rather than chaotic. Perhaps so orderly we would perceive their invisible involvement as natural laws rather than unusual miraculous intervention people usually expect from that sort of thing. Of course it's unprovable and even if you proved it it doesn't really contribute much to our understanding of the natural world, but it's interesting to imagine a form of life so orderly that we don't even perceive it as life but as part of the machinery of the universe.

keep_reading 3y ago
This hypothetical form of life -- what would its form of death look like? Where could we observe these dead angels / natural laws? If it can't die it's not alive
- hnlmorg 3y ago
  Why is it not alive? None of our current definitions of life, limited as they might be, require death as measurement. And just because life on earth is fragile, it doesn’t mean all forms of life have to be.
  - keep_reading 3y ago
    Death has to be a measurement. If it can live it can die.
    - hnlmorg 3y ago
      You haven't answered my question as to why.
  - deleted 3y ago

dieselgate 3y ago

Yeah I agree with this. In practice "who knows?!" what it could look like! But in theory, given the precedence available, I think it'd likely be similar to what we know (carbon, metabolism, maybe crab-like).

deleted 3y ago

[deleted]

someotherperson 3y ago

Would light-based lightforms know they exist? Would they even have an existence? It feels like it would be over the moment it begins.