chron44

If I may have some idea or vague opinion (being a layman in physics), is that the "construction" of nature (the physics part especially discussed) is fully dependent on how the universe truly is originated. The cosmological origin and further development set all such linear and non-linear, and other mathematical behavior by the original premises. I.e. if the BB is the cosmological origin, which much points on, the SM, QFT and the GUTs' among other BB sprung theories and its mathematics, all are part of the BB universal evolution line. Thus, this thread being a ToE parameters scrutiny also alternative cosmological origin ideas must be considered. Therefore, when GR have been verified so many times, this does NOT by automatics to 100% secure the BB cosmological evolutionary origin. And for to sum up my maybe a bit "easy and naive" arguing the "correct" cosmological origin does set the "fundamental thing about nature" where the "verified" GR may also suite different evolutionary lines.

Have in a layman’s manner tried to comprehend how GR works in an elementary manner. Can one easily describe adding mass and/or energy to a vacuum energy volume behaves like this? “I understand that G here is a very important constant (doesn’t change and sets the initial condition) and that the gravitational energy field is affected if mass or energy or both becomes present. One must hence note that the E=mc^2 very much influences the overall rise in this total resulting gravitational energy. -Like this famous "formula" is affecting all involved parts, the mass, the energy and the gravitational field in an intricate manner. In this way the spacetime “fabric” is altered and contributes to GR calculations being non-linear. Does this also mean that the energy related to only the gravitational field to a very extremely small extent is adding energy towards the present mass and energy? Yes, it does. “-Just like the dog is chasing its own tail”. 🙂 In this way it becomes hard to know how the total energy becomes configured. -Especially in extreme astrophysical conditions.” The underlying thought in this GR “statement” is the chase or hunt for the mystic G, the gravitational constant. Which must be an important part of a ToE’s parameters. (If I may alter a bit on the last posts focus.)

Tried to read this paper, and just focused on some paragraphs about noise at this type of detection attempt. The paper is declared/preceded in this manner: "Freeman Dyson has questioned whether any conceivable experiment in the real universe can detect a single graviton. If not, is it meaningful to talk about gravitons as physical entities? We attempt to answer Dyson's question and find it is possible to conduct an idealized thought experiment capable of detecting one graviton; however, when anything remotely resembling realistic physics is taken into account, detection becomes impossible, indicating that Dyson's conjecture is very likely true. We also point out several mistakes in the literature dealing with graviton detection and production." ~~~~~~~~~~~ ~~~~~~~~~~~ The (theoretical) answer is furthermore given on 22 pages including appendix. Here is the paper's aspect, specifically of noise, concerning any laboratory- graviton detection setup: Excerpt: "This result, however, does not absolutely exclude detection of gravitons; one can imagine filling the solar system and beyond with tiny detectors. At this point, though, the possibilities go out of sight. Before that point, we must address two other issues. The first is noise. Any detector needs to be shielded against background noise. Two serious noise sources are neutrinos and cosmic rays. The cross section for the interaction of neutrinos with matter is about 10^−45cm^2, or at least twenty orders of magnitude greater than the gravito-electric cross section. In a typical white dwarf, neutrino emission exceeds photon emission, meaning that 10^13−10^14 neutrinos are emitted for every graviton. Therefore, without shielding, one would expect 10^33−10^34 neutrino events for every graviton event. A shield should be thicker than the mean-free-path for neutrinos, which for materials of ordinary density amounts to light years. Such a shield would collapse into a black hole. Unless one can find another way to discriminate against neutrinos, this appears to make detection of thermal gravitons impossible. In light of this result, we do not pursue shielding against cosmic rays, which would activate the detector material, inundating it with secondary particles." End of excerpt. The famous words of: "Huston, we have a problem.", is in this context a huge understatement. -Though the reasoning of the graviton not being "necessary" in a ToE also has to be noticed. Concluding issue: Is this paper really to be considered for the real physics graviton laboratory research situation? For to answer this issue by myself, or to guess what pro physicists will say: Yep..!!

And, for not to mention, concerning the enormous challenges discovering the proposed spin-2 graviton. Isn't the quantum noise in any QM laboratory setup an almost overwhelming obstacle for the "clean" observation of the graviton? Besides the lack of any present coherent and useful theory with any such graviton search. So, the mathematics obviously have to lead in this type of research. (And may be the only manner in which the graviton "idea" is secured.) I would call this for the ultimate "ghost chase".

Of what I have so far understood is that there is the problem with the graviton and its UV divergence for suiting a quantized construction... This, when GR theory in combination with LIGO, among other observations, point on the spin-2 construction of the graviton. This 4th force really is a tough challenge for a ToE.

Interesting, so Einstein's field equations imply "its" most possible graviton construction? Or just the bare entities, without its presumed (QM?) properties, of the graviton and the gravitational waves? Still confusing when GR doesn't - normally - calculate with bosons. It's a QM matter. Where the analyze and theories from the LIGO, for example, indicates a spn-2 boson?

Ok. Still, this ToE issue is a bit more entangled, I suppose: First the reduced Planck's constant might be the "quantum floor" to our ability to measure physics, we still don't know if so. If this is the true physics measurement limit, and the graviton exist similar to our present proposed view of it, we can only notice and confirm the graviton indirectly from gravitational waves and through effects in cosmology, and so on. This scenario implies that a ToE theory can be "confirmed", with the unification of all 4 forces, by focusing on indirect evidence and buildings of a mathematically coherent theory that fits with experimental data from other areas of physics. The ToE issue seems to be delicate. In several manners.

So, either the graviton exists (the proposed spin-2 particle without mass) or not there is a possibility to craft a ToE. Is this what this cite means?

The reason is probably given why professional physicists tend to await any graviton confirmation, before even lifting the thought on any ToE. Hypothetical, in combination with extreme small energy and massless property. Like chasing ghosts... : )

Yes, of course, the graviton still is hypothetical. I didn't express myself clear enough. Still my intention with the latest post was to point out the theory of it; and some observations, LIGO and the one you mentioned, "showed" on the main characteristics for this proposed particle being probable. -And, here a most delicate situation emerges. Todays and the most ahead years of physics laboratory tech cannot provide any existing or non-existing status for this particle. This insecure status of the graviton idea will stall any further ToE research for many years ahead. With this reasoning any serious ToE arguing will fail. (Until the graviton's existence is confirmed. Or proven to be of a different construction.) So, ToE is halted.

The parameters to a ToE obviously have to incorporate gravity, of course. Which for the moment doesn't easily (not all all?) merge with QM. So here we, that "all" are aware of, stand with separate QM and GR. Though the detection by LIGO in 2015 did in some manner "reveal" possible internal structures and necessary conditions for gravity: * Being massless * Propagating at c * Probably existing in the entire known universe Which leads to the graviton existence proposed by the main physics community, maybe not the entire.

There was also a post from me (which disappeared) about one central marker of why GUTs are involved in a TOE speculation. And that is the detection of proton decay which is postulated from any (some?) GUT. -Still during about of 40-50 years of search no proton decay whatsoever have been detected. Where Mordred did replay (not exactly but informatively) of that the GUT calculus estimated the proton lifetime till over about 10^35 years, being the reason of no to date detection, as the age of universe being about one third of that age. So the GUTs still being on the track.

Have read a bit more physics... The GUTs (Grand Unification Theories) are based on very high energy systems, which should need a BB type of very/ extremely hot universe or a similar universal original evolution. In some manner the confirmation of any GUT would be a parallel indication of the BB besides the CMB radiation detection.

This is also fetched from Chat GPT: "When, GUTs are deeply connected to the Standard Model: -The cosmological constant problem and the non-observation of proton decay, looks like central challenges that have not outright disproven GUTs or the Standard Model but, have highlighted significant gaps in these theories." Can anyone comment these central discrepancies?

If a GUT is to be considered for ToE. One crucial issue becomes. How long can physics "wait" till a proton decay is noticed? -And therefore reasonably prove a GUT being the manner in which universe works? Have there been physicists who claim this period being fulfilled? ???

This is what I found from Chat GPT 3.5: "Grand Unification Theories (GUTs) aim to unify the three fundamental forces of the Standard Model into a single force at high energy scales. While several GUT models have been proposed (such as SU(5) and SO(10)), experimental evidence for key predictions, like proton decay, remains elusive. GUTs are considered a stepping stone towards an even more fundamental theory that would unify all fundamental forces, including gravity, in the quest for a Theory of Everything. However, many challenges and open questions remain, keeping GUTs at the forefront of theoretical research in particle physics." So, if I try to answer my issue myself, according to Chat GPT, GUT is in need of a rather or very hot universe (high energy scales) with a cooling down procedure. Where probably a BB or a resembling universal evolutionary frame is needed.

Much over my "normal" physics and math status. Did make a look on this paper and began to wonder: Does the origin of (our) universe, BB or any other universal evolutionary theory, matter within this paper's frames of reference? I.e. is the BB the only universal evolutionary candidate for this article? (Is it possible to estimate?)

This is how Wikipedia initially explains ToE. Excerpt: "A theory of everything (TOE), final theory, ultimate theory, unified field theory, or master theory is a hypothetical, singular, all-encompassing, coherent theoretical framework of physics that fully explains and links together all aspects of the universe. Finding a theory of everything is one of the major unsolved problems in physics." https://en.wikipedia.org/wiki/Theory_of_everything It's how ToE is defined. Maybe one can add chemistry and biology, but with another name or abbreviation.

Wasn't this the subject to discuss in this thread? And, personally of what I understand is that a ToE only is applicable to physics. Mathematics can cover "everything" and all disciplines. When the human world and conditions are limited. -Math has no boundaries to describe whatever. The "problem" with a ToE is that the human intellect for the moment lack knowledge about necessary parts of physics for to craft a ToE. The same goes for philosophy, it can analyze whatever, when it usually is regarding human conditions. So the difference between philosophy and physics, to my view, is that the first can cover whatever and physics is bound to the universal laws and conditions, which are limited. Still, maybe can be described with math. This is the challenging option in a ToE. This last issue is not quite regarding the initial quest of yours. It partly covers physics but mainly is a philosophical wondering. It's not physics. /chron44

Excerpt from a list of ToE criteria: (This page isn't in use anymore, not at least this posting presented here.) The green lines are some criteria for a ToE presented there, not all of them, thought. And the grey lines are my own comments for about 20 years ago, so have indulgence with my not that well understood remarks for each criterion given. (I didn't fully cope what the list maker had in mind.) I was most intrigued by this list then, and tried to comment and understand what the guy meant by his list. ~~~~~~~~~ ~~~~~~~~~ www.motionmountain.net/research.html#req 6. The fundamental constituents must determine all observables. They must also determine all coupling constants and particle masses. (If they did not, the theory would not be final.) This point, simply spoken, does support my thesis in some posts above here of the (correlation for) Microcosm and Macrocosm and ToE. But this list point is more or less precise about this criterion. 7. The fundamental constituents must be the only unobservable entities. (If they were observable, the theory would not be final; if more entities would be unobservable, the theory would be fiction, not science.) I don’t know how the list maker does argue for this point – but to my understanding the list maker does build this ToE criterion on the theory of quanta and QM. And also on the logical situation of only one unobservable. – If it were two or more – the logic and physics? in this ToE, would collapse. Probably the first part of point 7 is built or made upon the logical and physical? impossibility of two or more unobservable entities. The maker of this list has my regards of a physical and logical thorough understanding of the nature and the criteria of ToE. This judgment, by me, of the list is based of all list points. In fact I’m almost chocked over the way this list expresses ToE. I can here almost understand that Hawking and Mlodinow does throw in the towel – not by exhaustion – but by chock. That, for to return to point 7, the list maker only accepts one (1) unobservable is probably also based on the search of a “pure logic” that a ToE theory hopefully would manifest. (The human natural? search for truth and logic.) I must say that I’m a bit unclear about this point 7. It would be nice to hear what the list maker has to say about this. 8. Non-locality must be part of the description; non-locality must be negligible at everyday scales, but important at the Planck scale. (Otherwise, the contradictions between quantum theory and general relativity would not be solved.) This point is as it says based on quantum theory and GR and both having legal demands on a ToE. 9. Physical points and sets must not exist at Planck scale, due to limitations of measurement precision; points and sets must only exist, approximately, at everyday scales. (Otherwise, the contradictions between quantum theory and general relativity would not be solved.) This point Nr 9 does manifest the standard model of elementary particles – which almost all is confirmed. Only, for the moment, lacking one or two definitions. Simply this point does manifest particles as electrons or protons and such. 10. The final theory cannot be a set of equations. (If it were, it would contradict the limits to measurement precision.) This point Nr 10 is a hard criterion for a ToE. – But probably the list maker is right. A set of equations does probably diverge the mathematics and physics. Especially when ToE goes from Microcosm up till Macrocosm scale. The base equation would, of course, allow other equations drawn upon the base. But a set of independent equations does rather soon diverge the physical accuracy. How can Hawking and Mlodinow support such physics? OK, the list is astonishing, but also a bit chocking. Seeing forward to some other views. ~~~~~~~ ~~~~~~~ (Maybe the list is a bit obsolete these days.) /chron44

The energy associated with the Higgs field’s VEV, about 246 GeV, contributes to the overall vacuum energy of the universe. However, the contribution of the Higgs field to the vacuum energy is expected to be much larger than the observed value of the cosmological constant/ vacuum energy, leading to a significant discrepancy known as the cosmological constant problem. Why? (The cosmological constant is here in this issue treated same as the vacuum energy.) (Thus, the cosmological constant is the overall vacuum density. And the vacuum energy is seen as the fluctuations in various volumes of universe. Where the mean value is detected to about 3 GeV/m^3) The free speculation, given without proof, is that dark matter/ dark energy - yet not able to directly measure by some eluding reson. - Is involved into the Higgs field and its associated VEV. Maybe both or one of them. And it's most interesting that physics cannot directly detect these dark entities. Only observe them via the behavior of the galaxies, for example. The second speculation therefore becomes that this undetectable situation is based on the technology of how we measure in physics. And one example is that we use photons for to do this in some studies. Whereas the photon is regarded being a point particle with the smallest energy amount possible for to achieve any detection. (I am not directly referring to virtual photons, because these are mathematical "instruments", not "real" physical such. Although in the Standard Model virtual photons is regarded for real particles.) The second speculation hence becomes that we probably must "use" some "instrument" below the photon energy for to detect further physical stances. This is not yet possible. Why? /chron44

In QFT ... yes. There are excitations of the various fields which are perceived as virtual particles, or if above a quantum of energy, as real particles. In QFT, these fields require a background stage to act on. GR, on the other hand, has no background stage; space-time is an active participant. Isn't this post from MigL just like the saying by Confucius (which StringJunky uses) here we got two ways of narrative or definitions for "Space". Space is seen in two somewhat different manners - so we cannot be sure of how space is constructed in a general sense. In QFT the statement from me seems to be lucid. In GR, for example, this statement is not that comprehensive. ??? It seems like the original issue "What is Space made of?" has two somewhat different outcomes (at least in physics).

This is my general conclusion of this thread. Can anyone counter prove this statement? (Is it possible at all to do so?) /chron44

Hi, this thread was started in 2015 and has both puzzled and intrigued lot of posters here in Science Forums. Obviously, its's a subject which established, and "modern" physics has "indications" on, mainly from math in different sections of physics (GR, SR, QFT, SM, and so on). Still, the apparent quest "What is space made of?" first looks like a philosophical question, but when incorporating modern physics this issue converts to a rather legitimate and straight matter for all levels of physicists. This situation of today's puzzled stand probably is generally built from the introduction of Minkowski's space cone and the continuation with Einstein's and other physicists' concept of "spacetime" where space and time, both not so easy concepts, were mixed into rather or most complex mathematics. Probably, with fair reasoning, some of the posters here in this thread have made their own physical/ philosophical statements which "goes like the cat round the hot meal". Because this issue, to my view is both easy and complicated. And postulated or stated, Space itself can only be seen for an imaginary reference entity. -So, Space isn't made of anything. The physics math, isn't wrong either, because this math is a metaphor for Space (and other units) seen in a physics evolving tradition for to comprehend the world we live in. Being a physics site ppl ask for proof of the statement that Space is an important reference unit or entity. How can one prove this statement? For the moment I cannot do so. -Merely refer to other posts here in this thread, where some have expressed similar or adjacent ideas and thoughts. Still, if trying to prove that Space isn't made of anything, one can divide on matter and energy (fields) versus space. Space seems to be occupied with matter and energy fields. -Space itself is just a void that hold matter/ energy. Probably this isn't a justified proof of this subject. The proof lies somewhere in all the ppl who have made statements about this. The proof is the resulting collective statement by physics interested folks and professionals. Observe that novel physics mathematics only is a path to a more comprehensive understanding of the world and the universe. /chron44

OK, I notice your comment. All seems fair and representing today's cosmological physics. Also very distinct and compact expressed. For my own ideas of the cosmological evolution, I'll express them in the Speculation section. Just very interesten in cosmology and physics in general, and in a "layman" level.