With the caveat that I have nothing to do with ligo and so don't know much...
I think that during this ligo run (it just turned back on in April-ish) they expect to find roughly 1 event per week. So this will be fairly common! [1] is a nice summary of what they have found so far.
For people here interested in the engineering side of LIGO, it is absolutely mind blowing. The effect of the gravitational waves is tiny (fractions of the size of a proton change in length) and so there are so many things that need to be incredibly tightly controlled for. I went to a talk on this a year or so ago, but can't find the slides... Here's a summary [2] and the wikipedia page also has some info.
The gravitational waves in question have no quantum properties, either because they have so many quantum numbers in them that classical behaviour is recovered, or because they are classical “all the way down”. LIGO, its siblings, and their foreseeable successors are unlikely to help resolve this.
The results have already constrained the space of quantum gravity theories from which General Relativity must be recoverable, but that is not the same as preferring (much less indicating) any particular approach to quantum gravity that will be consistent with LIGO et al.’s results.
That said, LIGO’s detector itself relies upon the details of quantum mechanics, as it is also sensitive to quantum noise from its immediate environment. However the quantum mechanics in question are purely local, and have nothing to do with distant events like binary black hole mergers. (LIGO is not sensitive to those distant quantum mechanics — it’s either outright blind to them, or at best they blur into classicality — and it’s hard to envisage a human-buildable detector that would be sensitive to their gravitational influence within our solar system).
Is there such a thing as real phenomena that's classical “all the way down”, as you have put it? If yes, which such phenomena is easiest to understand?
I was under the impression that all of classical physics was special cases of quantum and relativistic physics, just like the relativistic equations of motion "degrade" into classical equations of motion when we postulate that all velocities involved are much lower than the speed of light.
In this sense "classical" means "not quantum". General relativity is "classic" in the sense that position and momentum are variables rather than operators. They have real values rather than functions.
So it's distinct from "classical" meaning "Newtonian" (or, perhaps "Newtonian + Maxwellian"), which is the sense in which "all of classical physics was special cases of quantum and relativistic physics".
Yes, all true, but we have the Hamiltonian formulation (e.g. https://arxiv.org/abs/1505.01403 which is a nice book chapter) which “… is also the starting point for the canonical quantization program, which constitutes one main approach to the as yet unsolved problems of Quantum Gravity. In this approach one tries to make essential use of the Hamiltonian structure of the classical theory in formulating the corresponding quantum theory.” From there you could jump to https://en.wikipedia.org/wiki/Canonical_quantum_gravity which has references.
Nobody knows. Gravitation might be classical “all the way down”. Dark Matter might not be quantum-mechanical. Few people really expect this though: either would be a surprise because as you say, for known macroscopic behaviours of matter they’re almost certainly
> special cases of [relativistic] quantum
and quantum mechanical objects even when doing funny quantum mechanical things will generate stress-energy and thus the stress-energy tensor (and thus the Einstein gravitational tensor) must reflect that. Unfortunately the obvious easy ways to do this (averaging the stress-energy tensor, quantum corrections to the metric using perturbation theory, second-quantizing the Hamiltonian formulation of General Relativity (cf. objections in near the start of [1]) …) have run into difficult problems. Mostly, however, the problems arise only when curvature is strong, and such strong curvature is hidden from us. These approaches work well for practically all the physics of uncollapsed stars, and a considerable amount of physics even in neutron stars. Thus we tend to say that we have various ways to turn classical General Relativity into an effective field theory [2].
We know — and can and do prove within our solar system — how errors arise in equations of motion that do not take relativistic speeds or non-flat spacetime backgrounds into account. In fact, we have some mathematical theorems about that, and reflect them in post-Newtonian formalisms and expansions, and have ample observational and experimental evidence supporting them. As a result, we can talk about the Newtonian limit and the flat-space limit of General Relativity, and we can derive the theories associated with those limits from the more fundamental theory of General Relativity (recovering Newtonian gravitation requires some extra tricks, and it’s those that help show why Newtonian gravitation is wrong; one is that the propagation of Newtonian gravitation is superluminal (technically infinitely fast) and this is contradicted by experiment (e.g. precession of Mercury’s orbit, MESSENGER, Hulse-Taylor, LIGO)).
Unfortunately we’re not as sure about the “errors” in classical matter theories as we fail to take quantum properties into account. It is a principle, rather than something stronger. In https://en.wikipedia.org/wiki/Correspondence_principle one finds: “This concept is somewhat different from the requirement of a formal limit”. We do not know how to derive numerous classical theories from quantum mechanics, correspondence principle notwithstanding, and so while one can claim that e.g. Navier-Stokes (“NS”) can be derived from the Standard Model, nobody has actually shown how to do this mathematically. Indeed, quantum theories of dissipative physics of all sorts are at best exceedingly rare [1], so in NS’s case viscosity has no derivation from quantum principles.
We don’t need anything at Planck energies to see a conflict between quantum field theories (QFTs) and General Relativity in the face of non-classical behaviour of matter which generates a strong signal in the stress-energy tensor. The main problem is that that such behaviours are “washed out” by the rest of the stress-energy tensor’s coupling to matter that is “in the classical limit”, and we don’t yet know how to recover classical physics from QFTs.
The interesting-to-theorists quantum gravity stuff is near the centres of neutron stars and black holes, and in the distant past of our universe: all regions we have yet to be figure out how to explore. And all those regions are surrounded by extremely hot and noisy matter: the ultradense nuclear pasta and hot atmosphere and so forth in neutron stars, the accretion regions of black holes, and the “fog” of the surface of last scattering (and the equivalent for neutrinos and possibly equivalent(s) for other non-charged particles or whatever the hell dark matter is). The closest neutron stars and black holes are already a depressingly long way away by RADAR-distance, so there’s no real hope of soon sending a probe close to them to try to gather up and report back observations. So theorists who want to abolish General Relativity’s gravitational singularity, or alternatively quantum things like unitarity, are struggling to extract (even in principle) signal from noisy relics of these extreme-and-hidden things.
However, there is still interesting stuff possible to test near us: if we can develop a laboratory-based object with strongly non-classical behaviour even at sufficient mass to influence lab gravimeters (that is, it will rise above the background stress-energy) then there are all sorts of things we can do to test theories of quantum gravity. We expect that semiclassical gravity will be blown away by such an experiment (there is a member of https://www.npl.washington.edu/eotwash/node/1 here on HN, for instance). An example might be to bring a milligram-or-more coherent mass into a superposition for at least a few milliseconds and see which way an array of lab gravimeters point. That’s already a difficult experiment! (the subsection heading is wildly optimistic, but explains the expected result of such an experiment: https://en.wikipedia.org/wiki/Semiclassical_gravity#Experime... )
I’m not certain the Planck length is anything more than mixing some physical constants into a unit of length, rather than something important to nature. It is interesting to see Planck-scale dimensionful units are frame-invariant — they might not be, which is the premise of Doubly-Special Relativity, for instance. On the other hand, Special Relativity and its deformations might not be the right tool anyway, as a Planck scale object may generate enough spacetime curvature (by virtue of the Planck scale object’s local stress-energy) to blow away the global symmetries of the flat spacetime that form the background for these theories (which are NOT background-independent!). We’re not going to be probing Planck scale objects in the near future, and so there are few limits on speculative theories other than re-re-re-reconfirmations of local Lorentz invariance at lower (stress-)energies in a variety of backgrounds, including that of the Standard Model of Cosmology (the red-shifting of spectra from supernovae, the Lyman-alpha forest, and so on), that of effectively flat spacetime (labs on earth, and in space vehicles around the solar system), and that of significantly curved spacetime (spectra of neutron stars, for instance). And that same information is also evidence favouring one QFT: the Standard Model of Particle Physics (“SM”), which incorporates Lorentz invariance (but not gravitation, so SM is background-dependent, and enjoys the fact that General Relativity predicts the correct background for SM in every sufficiently small region in the universe, even if the background between SM-event-at-A and SM-observer-at-B is such that a region covering A and B is clearly not flat spacetime []).
- —
[] we can adapt to that by using generally covariant physical theories; unfortunately not all physical theories have been “promoted” into general covariance, and anyway tensors are hard so people will use cut-downs of generally covariant theories adapted to some special background. One can study gauge fixing to figure out how well this works for physical theories, and whether the “comma-goes-to-semicolon” rule of “promoting” theories into general covariance actually ends up with something that works in an arbitrary background. Lots of perfectly-good-here-on-Earth physical theories fall apart in different spacetime backgrounds.
>One can study gauge fixing to figure out how well this works for physical theories, and whether the “comma-goes-to-semicolon” rule of “promoting” theories into general covariance actually ends up with something that works in an arbitrary background. Lots of perfectly-good-here-on-Earth physical theories fall apart in different spacetime backgrounds.
What? What is this "comma-goes-to-semi-colon" rule of "promoting" theories. This is either some superdense jargon I haven't been in the right place to encounter, or the research world has entered far stranger realms of symbolic representation than I've imagined possible.
Seriously, what am I missing? I'm assuming it has something to do with proving the consistency of theoretical frameworks by correlating them with empirical confirmation, but I'm not 100% sure I'm not stripping out important nuance.
Comma and semicolon typographical notation for partial resp. covariant derivatives. The comma is used to indicate a partial derivative: V^{\alpha}_{\comma\beta} = \partial_{\beta}V_{\alpha}. The semicolon V^{\alpha}_{\semicolon\beta} turns somewhat complicatedly (via Christoffel symbols) into \nabla{\beta}V^{\alpha}. There’s more detail at https://en.wikipedia.org/wiki/Covariant_derivative#Notation
These notations are reflected in “comma-goes-to-semicolon” which is discussed in MTW chapter 20 & 22 (esp. §22.4, Electrodynamics in Curved Spacetime) and other textbooks. Carroll’s online lecture notes at https://ned.ipac.caltech.edu/level5/March01/Carroll3/Carroll... discusses it briefly starting with the paragraph beginning “Our next task is to show how the remaining laws of physics…” and in particular (starting with) that paragraph’s penultimate sentence.
Even more briefly, we need generally covariant physics to escape the flat spacetime background into general curved spacetime and still get sensible electromagnetism and so on.
Even more briefly: the semicolon indicates a valid tensor equation, showing that we are fine when the basis vectors are not constant. Switching , to ; when it works hides away a bunch of work with Christoffel symbols, and what makes it work is the Equivalence Principle. Semicolon-goes-to-comma always works by gauge fixing, but unfortunately V^{a}_{,b} -> V^{a}_{;b} sometimes doesn’t; doing the full expansion by hand (well, or with modern automation) is one way to see if your physical theory is really generally covariant/background independent.
> superdense
Yes! As an example, and I haven’t really done more than scrub through it, and he really doesn’t go into any details beyond what you’d get in a standard textbook:
Putting the extra typographical dot on top of the , giving a ; can literally represent several pages of dense equations.
> jargon
Yes! A lot of writing that turns out to generally be really mechanical has been squashed out of General Relativity through the years. Unfortunately the notation itself — as typography — tends to “leak out”, so we talk about indices being in the basement or upstairs, Greek vs Roman, etc etc.
This will sound cynical, but at this point, it's no longer news unless it's a binary neutron star merger. If there's an electromagnetic counterpart, then it's big news.
If you have a gravitational wave detection with an EM counterpart, you can get a redshift and luminosity distance, which means that you can measure the Hubble constant (in a way that is completely independent from Type Ia Supernovae). Binary black hole mergers are not expected to give off any EM radiation.
There should be a few binary neutron star mergers this run, and with some luck, there may be one with an EM counterpart.
Presumably if the location could be determined accurately enough and it was close to a galaxy, we could conclude that it was most likely in that galaxy, and thereby get a useful measurement though?
People do want to correlate large numbers of binary black hole mergers with galaxy positions and come up with a statistical measurement of the Hubble constant, but no single BBH merger will be clearly identified with one galaxy under that scheme. You need lots of mergers, and the Hubble-constant determination is more model-dependent.
Binary neutron stars with EM counterparts are much more straightforward.
Yes, the experimental details are stunning, particularly with an experimental physics background.
As someone who had a narrow escape from a PhD working on resonant bar-type detection attempts, I've never understood how those were ever thought to be sensitive enough -- whether decent calculations just weren't available or what. Unfortunately, you're typically not in a good position to evaluate such things before starting the work.
Weber's initial calculations and experiments with bar detectors were a reasonable effort, because gravitational waves were something that nobody believed in. Bar detector has an advantage - it is cheap. A strong enough wave could excite it and it would have been great and cheap discovery. But later when nothing was being reliably detected, people turned to more expensive interferometric detector. Today it is believed the bar type detector could only detect extreme events nearby, which are very unlikely.
It is easier to understand if you imagine that they are "hearing" the gravitational waves instead of "seeing" the gravitational waves.
Analyzing how the waves affect both detectors and the delay, they can get a rough idea of the direction. The origin was in a single point that is probably in the dark zone in the bottom left.
I'm not sure of the reason of the shape, but resolving equations in sphere usually give curved solutions, and then projecting it to a planisphere add more distortion. [I'm interested to read a more detailed explanation. Also, why the longitude is in hours?]
It does come from a single point but they can not tell where inside the shaded area of space the single point was.
As far as I can tell from their website the event was seen by Virgo and only one of the Ligo detectors (Livingston), which makes localization in the sky rather uncertain. No clue at the moment why the second Ligo detector (Hanford) did not see it.
If not all of them see it and they have this shitty sky location, the one missing was either offline or its data was unusable for other reasons (ie someone left their phone on one of the mirrors and got a call).
If you had a working detector taking good data than not hearing it also tells you something. But if the detector was not taking good data for whatever reason (local seismic event, high surface winds, technical glitch), then it doesn't help you. Also afaik (and I am not an expert) the first automatic pipeline doesn't use non-detections.
Because it doesn't take infinite time from our perspective. The object falling into the black hole experiences strong time dilation due to the extreme gravitational field, but that doesn't affect a remote observer.
In the twin experiment, the observer sees his twin age slower, so it _does_ have a remote effect. From the perspective of the object falling into the black hole, the local conditions do not change, time is progressing normally etc.
I'm fascinated about the degree of automation. It seems that all the necessary computations are made and presented on that website. I would love to learn more about this and their tech stack.
Was there not some severe doubt on the whole signal inference? I recall an article that critized them for some changes in the protocol and also questioned the statistical significance of their findings. How is the current state of that discussion?
Pretty much dismissed by later analysis I believe. Also, please bear in mind LIGO/VIRGO pinned down a neutron star merger with an optical counterpart, so there is independent confirmation the detectors can lift signal out of the noise.
While I share your excitement at the wonders of the universe, the language you are using is confusing (borderline misleading). Gravity has very little to do with any interactions on a scale smaller than an asteroid (and definitely has nothing to do with chemistry or biochemistry). "Dispersal of some kind of quantum entropy" is not really a thing either, unless you interpret it to mean "something cool and sciency" (in which case, yes, unifying gravity and quantum mechanics would be as cool as science gets).
But the design of our circulatory system (to the degree we can talk about a "design") certainly is tuned the conventional gravitational gradient. E.g we have one-way valves in our leg veins to help keep blood from all pooling down there.
Likewise, our bones are continually restructuring their interiors according to the stresses resulting from experience of weight. I don't know of any evidence that the bone cells involved experience the weight directly, independent of the stress. There is pretty good evidence that they are responding directly, instead, to piezoelectric currents generated by the stress.
So, if the bone cells aren't experiencing gravitation, unmediated, their organelles certainly aren't.
Water does, though. So in this case gravity would be the water and boiling water would be a black hole.
One could argue boiling water adds entropy to a system (if its power source comes from outside the system) and that it's worth studying the effects of this added entropy in detail. Like how far do I need to be from the water to maintain homeostasis? Does the heated air around the water create small currents which cause a thunderstorm in Kansas? Testing these kinds of questions is essential to the scientific progress we've made which even allows us to definitively say what water is and isn't.
We don't know of any instances of life which developed "without gravity", whatever that means, since an object interacts with itself gravitationally. What would such a form of life look like? We don't know the full role gravity plays in the formation of life.
My intuition as somebody who worked in VFX with self affecting gravity and spent some time looking at simulations would be that self-effects are usually too small to really play a role in environments where all other forces are many magnitudes bigger.
But intuitions are often wrong, which is why looking at things in a micro gravity environment makes sense. This is why we do weak gravity experiments in the ISS right?
That isn't true. Our entire biological system evolved with gravity in mind; for proof, simply look at what is required of astronauts in deep space to prevent muscular and other cellular atrophy. Whether a similar system is achievable without gravity is out of scope; ours is dependent on it.
Ours as mammals maybe. But there is life "as we know" it that works perfectly fine without gravity. Just look at the recent news about fungi growing all over the ISS. No gravity necessary and quite obviously life by our standards.
Sorry; I didn't mean to flame anyone and will continue to adjust my responses to be more positive.
But come on dang, I got thrashed by a bunch of aggressive nonsense that doesn't belong on HN, with several direct attacks against my intelligence. I understand if saying someone has a snarky attitude is too much for HN, but I didn't insult anyone like several of the posters did to me.
I wouldn't have even posted the comment in the first place had I anticipated such a response from the community. I felt like I was defending myself the entire time. If I bared a little teeth in the process, I apologize and will continue to strive to improve my communication skills. However, rate-limiting me and not any of the users who were throwing around personal insults doesn't seem fair.
Believe me, I know the feeling. But in some of these cases, there's a primary commenter who putting energy into the argument long after it has become clear that nothing good will come of it, and that's the user we ask to stop. That's the impression I had of this very large, flamey thread.
I can't say I read these comments closely, though, or in many cases at all. We don't have the cycles to do that. If we missed cases of commenters being aggressive or otherwise breaking the site guidelines, that's likely why. You'd be welcome to point them out to us. There's certainly no intention at our end to take sides or scold you more than others.
I feign no hypothesis; I am only stating curiosities yet to be explored.
Almost every system down to our organelles depends on gravity in some direct or indirect way.
We still don't understand the relationship between quantum and classical mechanics. We don't have the answers to test any hypothesis about the relationship between quantum gravitational fluctuations and classical physical systems. But that hardly makes the curiosity absurd; in fact it will one day be the subject of many experiments.
Stop spouting this "even organelles need gravity" non-sense.
Also: Going from quantum mechanics to classical mechanics is well understood as the limit ħ -> 0. What we don't have a good handle on right now is the connection between gravity (as described by general relativity) and quantum mechanics.
You write: "Almost every system down to our organelles depends on gravity in some direct or indirect way."
Do you have any evidence of that? The equivalence principle says that force from gravity cannot be distinguished from the force due to an accelerated frame of reference.
For example, a spinning multi-generational star ship could have a 1 g pseudo-gravitational force on the inner surface, but no actual gravity - in the sense the requires quantum gravity - other than the weak gravitational force from distant stars.
If as you imply quantum gravity were essential to life, and such that life could not use a force like from rotating or accelerating, then it would disprove the equivalence principle and be worthy of a Nobel Prize.
Do I have any evidence towards my intentionally vague and open-ended assertation? Yes, for the individual systems which are dependent on gravity in some way which we have studied. There are already examples in this thread.
I don't understand how the equivalence principle matters here. If you placed a system within another system which perfectly mimicked the gravity created from mass via just acceleration, then the system never knows the difference. That is the equivalence principle, and it doesn't have much to do with what I'm discussing here. What I'm discussing is the yet unstudied emergent effects of massive, far-reaching gravitational perturbations in... stirring the pot, so to speak.
If acceleration sufficiently mimics gravity such that living systems cannot tell the difference then it's 1) not really true that life requires gravity, and 2) it certainly doesn't require quantum gravity.
You still haven't demonstrated where "chemical reactions in our organelles" are meaningfully affected by gravity. All the references you've given are for much larger systems.
Excuse my language, but I want to stress how preposterous this statement is: this is complete and utter nonsense. Gravity is way more than 10^10 times weaker than electromagnetism at this scale.
Unless you mean "gravity is important to make planets, and planets are where we have observed life", in which case you are stretching the meaning of this expression to a meaningless level.
The cell is not a natural homogeneous mixture obeying the laws of free energy. It is actually a densely packed collection of mechanisms designed to subvert free energy and selective cause otherwise improbable reactions to occur. It ought not to be a surprise that some of those mechanisms do not work so well outside the standard uniform gravitational field we experience.
But that is not to say that there isn't another set of mechanisms that could work without the influence of gravity. You can see this in parallel with human construction: stairs don't work so well without gravity, but ladders work perfectly fine.
> It ought not to be a surprise that some of those mechanisms do not work so well outside the standard uniform gravitational field we experience
This is called a dependency. So you agree with my initial proposition.
> But that is not to say that there isn't another set of mechanisms that could work without the influence of gravity
As I addressed in another post, this is orthogonal to the discussion because we are talking about the universe the way it is, not the way it could be; If we remove gravity from the equation, we don't even get past the big bang and forming systems from uneven matter distribution.
Your original proposition is "[gravity is] required for [...] chemical reactions in our organelles."
I am explicitly disagreeing that gravity is required for such reactions. Your own source doesn't back up that statement--it suggests that the microstructure (in addition to the more obvious structure of the intercellular matrix) of cells is influenced by gravity, which is itself a rather different statement. Influence is a very different thing from requirement.
Furthermore, I should point out that our experience that life can survive quite well outside of the normal gravitational field is itself sufficient disproof of your proposition. After all, our mitochondria don't go "Wait! There's no gravity! How am I supposed to Krebs cycle now?"
I said indirectly, so if you're going to quote me don't only quote the parts that feed your take on things.
> I am explicitly disagreeing that gravity is required for such reactions
A dependency is very different from a requirement. You can have one without the other. But a system's growth being influenced by an outside system explicitly means that the system's current structure is dependent on that outside system; in the sense that if the outside system were never present, the internal system would be structured differently if it existed at all. And that is only talking about direct influence.
> Furthermore, I should point out that our experience that life can survive quite well outside of the normal gravitational field is itself sufficient disproof of your proposition
You are straying sooooo far from my original post, can we reel it in a little bit?
Okay, I read it. It's an editorial. It says nothing about how gravity is required "for heavy elements to cluster in one place in sufficient concentrations to form organelles".
For the matter, it says nothing about heavy elements.
These two links still have no bearing on the topic.
You wrote "Gravity is important for heavy elements to cluster in one place in sufficient concentrations to form organelles."
Your link #1 concerns blood flow, which is much larger than organelles and has nothing to do with heavy elements. (In any relevant sense - while red blood cells have iron, they don't affect the fluid dynamics.)
Your link #2 barely touches on gravity, and doesn't mention organelles or heavy elements.
I agree with krastanov - the statement of yours, which I quoted, is preposterous according to a widely held understanding of how things work. As such, it would require strong evidence to overturn those views.
What is the basis by which you decided it was correct and important enough to bring up?
Sure, organelle formation probably has little to do with gravity. You seem very devoted to this semantic battle. Would you like to take this conversation elsewhere?
Grice's razor: "As a principle of parsimony, conversational implications are to be preferred over semantic context for linguistic explanations."
People fall into semantic battles when they don't feel qualified to discuss the real substance of the conversation. A pity, I was hoping for some stimulating discourse and not a bunch of egotistical hogwash missing the entire point of my proposition.
While OP's words are his own and I'm not necessarily in agreement with them, it's worth pointing out that the circulatory system and organs and organelles which comprise them all have circular dependencies; it's not simply hierarchical based on relative size. A change in any part of the system can propagate both upward and downward.
As to your 'circular dependencies', I'll again quote krastanov in the direct ancestor to this thread:
> Unless you mean "gravity is important to make planets, and planets are where we have observed life", in which case you are stretching the meaning of this expression to a meaningless level.
This 'circular dependencies' argument is as meaningless as saying that biological organelles are essential to the production of nuclear weapons - true, but not important enough that it's needed to understand the overall process.
And there are many things like that. We can model weather numerically without modeling each and every molecule because that low-level interaction doesn't really affect fluid dynamics. Mean field theory can be apply to many complex systems.
Yes, there can be chaotic behavior, even in Newtownian systems. But that's beside the point, which is they you have made statements which you seem to assert as fact which don't have any evidentiary support.
You might as well muse about the effects of feline ESP on the weather.
I think you’re confusing me with soulofmischief. In any case, I think I’ve clarified what I meant by my statement: organelles exist because gravity has caused heavy elements such as carbon and oxygen to be present in a dense enough concentration for life to occur.
I understand where you're coming from. You're talking about stellar dispersion of elements-- which is true. Somehow this isn't relevant to forming life? I guess that's why none of the people shitting all over my musings in this thread are actually working in Physics and not just recounting what they read in a Pop Sci article. Dunning-Kruger effect, I guess.
My disappointed comment at your musings (which I would characterize as misleading or at the very least nonsensically general truisms) started this regrettable thread. While I avoided commenting in it, this last comment of yours just continues the misleading pretentiousness: unlike what you assumed, some of the people that argue with you actually work in Physics, and we are annoyed because you conflate phenomena and then project and argue about meaningless semantics. As I said, I do share your excitement at the wonders of the universe, but I am trying and failing to see intellectual honesty or awareness in most of your follow-up comments.
You're confusing me with another poster, dawg. I said nothing about heavy elements.
> 'circular dependencies' argument is as meaningless as saying that biological organelles are essential to the production of nuclear weapons
Lol okay, or we could actually be mature about this and stay within the bounds of the discussion. Yes, it's meaningless when you stretch it that far; but I didn't. These systems are in direct contact with each other and depend on each others' designs to function. That has nothing to do with nuclear weaponry.
> We can model weather numerically without modeling each and every molecule because that low-level interaction doesn't really affect fluid dynamics
Yes, that's called classical mechanics. We wouldn't rely on QM to describe large-scale weather phenomenon which our current laws of classical thermodynamics encapsulate just fine. But these are all models, not reality itself; If we found out tomorrow a GUT which directly modeled quantum perturbations all the way to a storm in Kansas, with high accuracy, we would use that instead. So referencing our current applications of our current immature physical theories is pointless to this conversation.
> You might as well muse about the effects of feline ESP on the weather.
You just cannot have an open-minded scientific conversation can you? It just has to be a chance to show your intellectual superiority? Hardly a conducive attitude for progress and breaking the status quo. At one time Newton was considered nuts. At one time Einstein wasn't taken seriously. I'm not Newton or Einstein but neither of their bodies of work were developed having conversations with people like you.
More to the point, your derision is ill-formed; Comparing quantum gravitational fluctuations to ESP is just insane. One of them is very much real and proven. We just don't have a GUT to tie it all together.
While technically present at all scales, gravity is so weak that you can ignore it until you get to pretty large scales. Meters or so. An ant barely feels gravity, a bacterium or a single cell don't even know it is there.
What does it mean to "feel" gravity? I assure you the ant's biological systems would undergo many changes over generations in the absence of gravity in order to reach homeostasis. A bacterium can't feel anything but did I mention single-celled organisms? No, I mentioned organelles. You are arguing against a straw-man.
Furthermore you are completely ignoring the effect of gravitational perturbations on emergent structures. These things don't necessarily "iron out", and if they do, we have not yet ascertained at what level and via what mechanism.
You are confusing an object's ability to produce gravity with its propensity for interacting with gravity.
You're right; I'm just trying to not stray so far from the intending meaning of my post. However, our organelles are indirectly influenced by gravity as a result of cascading interactions with other macro systems.
I'm just sure someone could make the argument that one bacteria out there was shown to function identically without gravity, thus dismantling an argument I was never trying to make. Organelles are different because they interact with a larger cell structure, which interacts with a larger tissue structure, the latter two both having experimentally proven dependencies on gravity for optimal performance in their current structure. Yes, a lot of our cells would work more or less the same in zero grav-- but would they have ever formed that way in the first place? Your guess is as good as mine.
I think that during this ligo run (it just turned back on in April-ish) they expect to find roughly 1 event per week. So this will be fairly common! [1] is a nice summary of what they have found so far.
For people here interested in the engineering side of LIGO, it is absolutely mind blowing. The effect of the gravitational waves is tiny (fractions of the size of a proton change in length) and so there are so many things that need to be incredibly tightly controlled for. I went to a talk on this a year or so ago, but can't find the slides... Here's a summary [2] and the wikipedia page also has some info.
1 - https://www.sciencenews.org/article/ligo-virgo-made-5-likely... 2 - https://www.engineering.com/Education/EducationArticles/Arti...