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What no one has seen before: gravitational waveforms from warp drive collapse

arxiv.org

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Re: What no one has seen before: gravitational waveforms from warp drive collapse

#31

Post by rini17 »

WJW wrote: post #12
perihelions wrote: post #10

Huh, so you can hear things explode in space, after all. If you're close enough to a warp field doing funny things, the gravitational wave strain would create audible-frequency artifacts, as it wiggles your eardrums at frequencies close enough to the audible. They derive an equation for estimated strain as a function of distance from the warp bubble collapse. How does strain translate to sound intensity, in the situa…

Would it even wiggle the eardrums relatively to the rest of your head? Intuitively it seems that would only happen if the wavelength is exactly right, but at that wavelength the frequency would be inaudible because the speed of light is so high.

It can move soft tissues relatively to the skull bone, resulting in changes of pressure detectable by eardrums.

Re: What no one has seen before: gravitational waveforms from warp drive collapse

#32

Post by rini17 »

JumpCrisscross wrote: post #11
gorkish wrote: post #2

Funny that the sci-fi got it backwards. It seems rather obvious in hindsight that should it even be possible, we will clearly be able to detect warp signatures far before we would be able to build a machine capable of producing them.

> we will clearly be able to detect warp signatures far before we would be able to build a machine capable of producing them We’re in the crystal-radio stage of gravitometrics.

Not even that, spark gaps and coherers :)

And we can't really detect radio signatures yet, not farther than closest stars. Perhaps when we get solar gravitational lens telescopes.

Re: What no one has seen before: gravitational waveforms from warp drive collapse

#33

Post by dotancohen »

hedora wrote: post #18
perihelions wrote: post #10

Huh, so you can hear things explode in space, after all. If you're close enough to a warp field doing funny things, the gravitational wave strain would create audible-frequency artifacts, as it wiggles your eardrums at frequencies close enough to the audible. They derive an equation for estimated strain as a function of distance from the warp bubble collapse. How does strain translate to sound intensity, in the situa…

I imagine the sound of the hull + everything else shuddering would probably dominate the perceived sound from eardrums or direct excitation of the air.

The hull is in a vacuum, and so are the eardrums.

Re: What no one has seen before: gravitational waveforms from warp drive collapse

#34

Post by kragen »

kelseyfrog wrote: post #14
gorkish wrote: post #2

Funny that the sci-fi got it backwards. It seems rather obvious in hindsight that should it even be possible, we will clearly be able to detect warp signatures far before we would be able to build a machine capable of producing them.

Except now the dark forest hypothesis precludes the development and use of warp drives with detectable collapse signatures.

so if we detect them we know it's false; that's very significant

Re: What no one has seen before: gravitational waveforms from warp drive collapse

#35

Post by joe_the_user »

gorkish wrote: post #2

Funny that the sci-fi got it backwards. It seems rather obvious in hindsight that should it even be possible, we will clearly be able to detect warp signatures far before we would be able to build a machine capable of producing them.

I don't think warp drives would be different from other kinds of waves expanding in space - their strength would normally decrease at least the square of the distance simply because their energy wouldn't have a direction. And if the energy did have a direction, the odds of it being aimed at earth would be small.

For that reason, only warp drive harnessing star-equivalent energy levels would be visible at distance of stars and so-on. I mean, Fermi's observation comes down to "there's no intelligent-being signature at the star-levels of energy we can see". But that could be because: intelligent beings are rare or because harnessing star-levels of energy is hard or impossible no matter how advanced a society gets or advanced societies have no need for such harnessing or because advanced societies follow the paranoid "dark forest" logic.

Re: What no one has seen before: gravitational waveforms from warp drive collapse

#36

Post by causality0 »

ganzuul wrote: post #8
largbae wrote: post #6

This is excellent. Like the Dyson sphere, predicting signals for technologies that we can imagine but not yet construct seems like a great way to guide our search for other life. Now we need a team of smart folks to identify tearing or other processing anomalies in universe-scale simulations.

If you like spooky stuff there is lots of fun things to think about. Just off the cuff; We are predicting a soul upload technology with Neuralink etc. So an alien technosignature could look like: https://en.wikipedia.org/wiki/21_grams_experiment This one is not rigorous but there are lots of other possibilities of this pattern.

At absolute best, it would be soul copying, not uploading.

Re: What no one has seen before: gravitational waveforms from warp drive collapse

#37

Post by chownie »

jvanderbot wrote: post #30
ben_w wrote: post #28

Earlier quoted context omitted.

One of the reasons I no longer ask questions on Physics stack exchange: 1. I asked "how powerful" such waves would have to be to be audible. 2. I directly linked to another question whose accepted answer said "these waves can wiggle your ear drum" 3. Got my question closed as a duplicate but the link was to different question that only asked "is it possible" (and accepted the answer "yes") without there being any ans…

The moderation on SE is abysmal, but it's the best moderation around for such a large, universally accessible, user-submitted knowledge store.

A better form of moderation exists in the form of whatever they were doing before, when you could ask a question and get an answer.

At one point SE was my most used resource. As of now I haven't used SE at all for I think four years. Why would you, when so much of the site's content is outdated and the moderators enforce that situation?

Re: What no one has seen before: gravitational waveforms from warp drive collapse

#38

Post by amelius »

rini17 wrote: post #31
WJW wrote: post #12

Earlier quoted context omitted.

Would it even wiggle the eardrums relatively to the rest of your head? Intuitively it seems that would only happen if the wavelength is exactly right, but at that wavelength the frequency would be inaudible because the speed of light is so high.

It can move soft tissues relatively to the skull bone, resulting in changes of pressure detectable by eardrums.

So those whooshing sounds of spaceships in sci-fi movies/series were real after all ...

Re: What no one has seen before: gravitational waveforms from warp drive collapse

#39

Post by rachofsunshine »

ben_w wrote: post #28
perihelions wrote: post #10

Huh, so you can hear things explode in space, after all. If you're close enough to a warp field doing funny things, the gravitational wave strain would create audible-frequency artifacts, as it wiggles your eardrums at frequencies close enough to the audible. They derive an equation for estimated strain as a function of distance from the warp bubble collapse. How does strain translate to sound intensity, in the situa…

One of the reasons I no longer ask questions on Physics stack exchange: 1. I asked "how powerful" such waves would have to be to be audible. 2. I directly linked to another question whose accepted answer said "these waves can wiggle your ear drum" 3. Got my question closed as a duplicate but the link was to different question that only asked "is it possible" (and accepted the answer "yes") without there being any ans…

I worked this out once!

Gravitational waves obey the inverse-square law much like most radiation does (and subject to some constraints about weird spatial geometry, but most of their propagation is going on in open flat-ish space, so we can ignore that).

GW150914, the first gravitational wave observed, had an amplitude of about 4 times 10^-22 [1], i.e., differences changed by a factor of about that. Typical sound displaces the eardrum by on the order of half a micron or so [2], with the threshold of hearing at about 100 nm. The inner ear's shape is curved, but linear length is on the order of 10 mm [3] (it curves around so the total length is longer, but the gravitational wave would be transverse along its length).

A 100 nm displacement on a 10 mm length is a relative change of (100 x 10^-9) / (10 x 10^-3) = 10^-7, that is, 4 times 10^-17 times larger than the gravitational wave detected. That gravitational wave was emitted at a distance of about 410 Mpc [1], and so we can solve:

(d / 410 Mpc)^2 = 4 x 10^-17

d^2 = 4 x 10^-17 * (410 Mpc)^2

d = 2 parsec.

Granted, this is at the limit of hearing for a very brief sound (the sound was only in the human audible range for about a tenth of a second). You'd need to be perhaps 10 times closer - about 20,000 AU - for it to be a loud sound under these assumptions.

Of course you wouldn't be around to hear it for very long because you're 20,000 AU from one of the most energetic events in the cosmos, but hey, you'd hear a brief "click". Totally worth being vaporized.

[1] https://en.wikipedia.org/wiki/First_observation_of_gravitati... [2] https://biology.stackexchange.com/questions/79963/how-far-do... [3] https://www.verywellhealth.com/inner-ear-anatomy-5094399

Re: What no one has seen before: gravitational waveforms from warp drive collapse

#40

Post by dheera »

joe_the_user wrote: post #35
gorkish wrote: post #2

Funny that the sci-fi got it backwards. It seems rather obvious in hindsight that should it even be possible, we will clearly be able to detect warp signatures far before we would be able to build a machine capable of producing them.

I don't think warp drives would be different from other kinds of waves expanding in space - their strength would normally decrease at least the square of the distance simply because their energy wouldn't have a direction. And if the energy did have a direction, the odds of it being aimed at earth would be small. For that reason, only warp drive harnessing star-equivalent energy levels would be visible at distance of…

Another theory I have is that truly sufficiently advanced societies stop giving a shit. They figured out how to be in equilibrium with their resources and are capable of being happy that way.

Giving shits about things is one of the big reasons we have wars and other potentially civilization-ending possibilities.

Even if we are able to put 100 humans on a spacecraft for 100 years hurtling across the galaxy I'm pretty sure they'll start fighting among each other after 2 years. It's one of the reasons that I think we'll need to make embodied AGIs that are less prone to fighting to continue the legacy of civilization long term.

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