7 ms·

So, going from a very narrow frequency band (up to 1000Hz) to a much wider range, which can theoretically encode information (e.g. frequency modulation)... Hmm,

So, going from a very narrow frequency band (up to 1000Hz) to a much wider range, which can theoretically encode information (e.g. frequency modulation)... Hmm, I'm wondering if comms over gravity is something a sufficiently advanced civilization might consider using, and should we be looking for that 'Hello, world' in some 'natural frequency' like we're doing for EM radiation?

jimbokun 2y ago
Did you read Death's End by Cixin Liu?
serial_dev 2y ago
If we are going all in on imaginary civilizations, even a very narrow (well, not that narrow) frequency band could be used to encode information, couldn't they?
- gadilif 2y ago
  Yes, but not efficiently (it will be very slow) and will be hard to detect because of noise (the article mentions the 'cacophony' of gravity noise). This is similar to EM radiation, so, you do frequency modulation (or amplitude, but that seems harder with gravity - you'll need to modify mass...), so you have a base high frequency on top of which you add lower frequency. The substraction later gives you a clean signal (or, Gravity Radio).
  - vbezhenar 2y ago
    Will you distinguish it from noise? Surely those will be compressed and encrypted.
    - gadilif 2y ago
      Some of it, definitely. But if the purpose is to seek others and announce yourself (like we did with Voyager 1 and 2), then you'll want it to be plain. Also - Public radio transmissions are not encrypted (as your purpose is to have as many listeners as possible... You monetize on ads).
  - anyfoo 2y ago
    I'm not sure "slow" matters that much. If (and that's a big if) there is advantage to announce yourself to other civilizations using gravity waves, instead of other means, then it probably does not matter too much if transmitting a reasonable amount of information takes a decade or so. You'd put it on repeat of course, and hope that interested civilizations don't have too short of a lifespan to still make sense of it.
BurningFrog 2y ago
I can't really imagine how such a transmitter works? Somehow moving planet sized objects around to create gravity waves? Of course, the cop-out "using their advanced tech we don't have a clue about" answer could actually be correct.
- vbezhenar 2y ago
  Create tiny black holes and throw them into each other.
qual 2y ago
I'm not sure I see what the advantages of communicating this way would be. The amount of energy required per bit transmitted would be astounding. I feel like, while theoretically possible, it's pretty much all downsides and no upsides. At least for communication purposes. However, your comment reminded me of an interesting PBS Space Time episode discussing the possibility of finding alien civilizations via the gravitational waves produced by their massive ships accelerating to near light speed. https://www.pbs.org/video/could-ligo-find-massive-alien-spaceships-vwlvoz/ https://www.pbs.org/video/could-ligo-find-massive-alien-spac...
- gadilif 2y ago
  Thanks for the PBS reference, interesting! As to the energy required, well, yes, I guess manipulating huge masses will be costly, but, if there is an efficient way to do this, then gravity waves are a parallel plane of communication. The analogy I heard once is about tribes communicating with smoke signals, while the air around them is filled with radio waves. Maybe we can't hear anyone out there because we're not listening to the right thing...
- colmmacc 2y ago
  The medium is the message. If we detected a modulated signal in gravitational waves, it would be like an Iron Age tribe receiving a 100 foot tall perfectly polished stainless steel statue with ornate inscriptions and pictograms. It would be recognizable and within our conception, but it would also be a demonstration of development and access to resources beyond our imagination. That's the upside. In a galaxy of sparse and sparingly advanced civilizations, the message might be "fear us and stay away" in a way that EM would not convey.
  - qual 2y ago
    >it would also be a demonstration of development and access to resources beyond our imagination. That's the upside [...] In a galaxy of sparse and sparingly advanced civilizations, the message might be "fear us and stay away" in a way that EM would not convey. I think you've hit the crux the question. If there are only a few civilizations, I agree, that'd be an awe-inspiring deterrent. However, if you don't know how many civilizations there are that are similarly advanced to your own, sending out a big "we're here!" message may be quite risky. In terms of game theory, it's a sequential and incomplete information game. I think the smartest decision is to remain quiet.
brianjlogan 2y ago
Since gravitational waves would still be restricted to the speed of light what would the benefit be? Would "obstacles" be circumvented? I would think interference would still be possible but instead of line of sight it would be large gravitational distortions (black hole, stars). Humility clause: I don't know what I'm talking about.
fsmv 2y ago
This idea was featured in The Three Body Problem trilogy. The problem is modulating the signal. The only way is to move large masses quickly.
- alfiedotwtf 2y ago
  I'm thinking you could also create gravity waves by annihilating matter and then creating matter over and over. If you could get a bit of that wave to reflect back to you and then sync your creation/annihilation, you could build a huge wave over time
imoverclocked 2y ago
Lots of naysayers but I can think of one very valid reason this might be the case. Our species, and many species on our planet, can see a very narrow band of the radiation spectrum. It’s possible an advanced civilization never developed that but was instead far more intimate with gravitational energy instead. We are talking about the universe after all.
elihu 2y ago
"Zorlax the mighty would like to connect on LinkedIn" https://xkcd.com/1642/ https://xkcd.com/1642/

jimbokun 2y ago

Did you read Death's End by Cixin Liu?

serial_dev 2y ago

If we are going all in on imaginary civilizations, even a very narrow (well, not that narrow) frequency band could be used to encode information, couldn't they?

gadilif 2y ago
Yes, but not efficiently (it will be very slow) and will be hard to detect because of noise (the article mentions the 'cacophony' of gravity noise). This is similar to EM radiation, so, you do frequency modulation (or amplitude, but that seems harder with gravity - you'll need to modify mass...), so you have a base high frequency on top of which you add lower frequency. The substraction later gives you a clean signal (or, Gravity Radio).
- vbezhenar 2y ago
  Will you distinguish it from noise? Surely those will be compressed and encrypted.
  - gadilif 2y ago
    Some of it, definitely. But if the purpose is to seek others and announce yourself (like we did with Voyager 1 and 2), then you'll want it to be plain. Also - Public radio transmissions are not encrypted (as your purpose is to have as many listeners as possible... You monetize on ads).
- anyfoo 2y ago
  I'm not sure "slow" matters that much. If (and that's a big if) there is advantage to announce yourself to other civilizations using gravity waves, instead of other means, then it probably does not matter too much if transmitting a reasonable amount of information takes a decade or so. You'd put it on repeat of course, and hope that interested civilizations don't have too short of a lifespan to still make sense of it.

BurningFrog 2y ago

I can't really imagine how such a transmitter works? Somehow moving planet sized objects around to create gravity waves? Of course, the cop-out "using their advanced tech we don't have a clue about" answer could actually be correct.

vbezhenar 2y ago
Create tiny black holes and throw them into each other.

qual 2y ago

I'm not sure I see what the advantages of communicating this way would be. The amount of energy required per bit transmitted would be astounding. I feel like, while theoretically possible, it's pretty much all downsides and no upsides. At least for communication purposes. However, your comment reminded me of an interesting PBS Space Time episode discussing the possibility of finding alien civilizations via the gravitational waves produced by their massive ships accelerating to near light speed. https://www.pbs.org/video/could-ligo-find-massive-alien-spaceships-vwlvoz/ https://www.pbs.org/video/could-ligo-find-massive-alien-spac...

gadilif 2y ago
Thanks for the PBS reference, interesting! As to the energy required, well, yes, I guess manipulating huge masses will be costly, but, if there is an efficient way to do this, then gravity waves are a parallel plane of communication. The analogy I heard once is about tribes communicating with smoke signals, while the air around them is filled with radio waves. Maybe we can't hear anyone out there because we're not listening to the right thing...
colmmacc 2y ago
The medium is the message. If we detected a modulated signal in gravitational waves, it would be like an Iron Age tribe receiving a 100 foot tall perfectly polished stainless steel statue with ornate inscriptions and pictograms. It would be recognizable and within our conception, but it would also be a demonstration of development and access to resources beyond our imagination. That's the upside. In a galaxy of sparse and sparingly advanced civilizations, the message might be "fear us and stay away" in a way that EM would not convey.
- qual 2y ago
  >it would also be a demonstration of development and access to resources beyond our imagination. That's the upside [...] In a galaxy of sparse and sparingly advanced civilizations, the message might be "fear us and stay away" in a way that EM would not convey. I think you've hit the crux the question. If there are only a few civilizations, I agree, that'd be an awe-inspiring deterrent. However, if you don't know how many civilizations there are that are similarly advanced to your own, sending out a big "we're here!" message may be quite risky. In terms of game theory, it's a sequential and incomplete information game. I think the smartest decision is to remain quiet.

brianjlogan 2y ago

Since gravitational waves would still be restricted to the speed of light what would the benefit be? Would "obstacles" be circumvented? I would think interference would still be possible but instead of line of sight it would be large gravitational distortions (black hole, stars). Humility clause: I don't know what I'm talking about.

fsmv 2y ago

This idea was featured in The Three Body Problem trilogy. The problem is modulating the signal. The only way is to move large masses quickly.

alfiedotwtf 2y ago
I'm thinking you could also create gravity waves by annihilating matter and then creating matter over and over. If you could get a bit of that wave to reflect back to you and then sync your creation/annihilation, you could build a huge wave over time

imoverclocked 2y ago

Lots of naysayers but I can think of one very valid reason this might be the case. Our species, and many species on our planet, can see a very narrow band of the radiation spectrum. It’s possible an advanced civilization never developed that but was instead far more intimate with gravitational energy instead. We are talking about the universe after all.

elihu 2y ago

"Zorlax the mighty would like to connect on LinkedIn" https://xkcd.com/1642/ https://xkcd.com/1642/