guardian

Check out this applet that shows the group velocity faster than c. Click on the applet to see the apparent 'signal' travelling backwards - seemingly from the destination to the source Check out the other applets too - quite interesting.

I seem to distinctly remember something I read recently about fractal dimensions and that they can be irrational. That may not be what you're after though. If it, is perhaps mathematics/geometry is a more appropriate section.

Interesting. I am not too fussed (at this stage) about the multiple time dimensions he mentions in the intro however after reading the first lecture notes (pdf) that he presents I would be very interested to know whether the GPS anomalies, orbit decays (spin down) and other anomalies presented coupled with the rotating reference frame (& the radius curve) are still valid and 'unsolved' by physics. Many references presented with regard to these anomalies are from the 60's 70's and 80's. Have these been solved or could this guy really have valid answers to something (even if he is a biologist) that physicists have been puzzled by to this day? I would really like to know more about the things this guy is claiming to have solved. He seems to be making a lot of sense and testable predictions that, if found correct, could humble a many physicist. Please enlighten.

I would say energy is THE entity - not another. Matter is, amongst many, one of the effects of energy and when this happens, it can be thought of as a property of matter. Just the way I interpret it.

Thank you Atheist. ...to be entirely correct I wasn't asking for an explanation of 'why' HERE, I was asking whether it was so difficult. Usually when someone asks a question (even in the form that I used), 'physics experts' will give reasons for their answer. The intriguing part was that it took some 6 days to answer something that seems so simple even if it was a 'non' by a (presumably) non-expert. Now back on topic...

I agree with Swansont also. Time is relative. But what is disheartening is that Einstein (from what Bettina has mentioned) is allowed to imagine himself riding a beam of light - yet when I ask a question Is it sensical or non-sensical to use a photon reference frame...I get nothing (for a long time) and then a "non". Hmmm. Is it really that difficult to succintly describe why or why not? I go with Einstein and ride the light - afterall the photon is doing it and still gets to interact. I digress...

Martin, one other thing that has left the preon model incomplete - angular momentum? Or did I miss something...hmmm Still haven't watched the presentation in its entirety but I AM interested in the Q-A section. Oh, and another thing. Although it says it has solved the asymmetry problem - the asymmetry persists! We still have dominance of matter.

Took slightly longer for me to get going since I had to d/load some sort of a decoder. Watched 13 mins. but cannot watch the rest yet. Although more appealing as a visual presentation I get a feeling it'll be a rehash of the paper (apart from the background - ie prior versions of preon model), am I right? I understand the paper completely. Are there things in the presentation (again bar the background) that are not covered in the paper?

That would be 'limited' type of thinking but if you can get a good enough grasp of 'nothing' then talking about boundaries loses its meaning ie. becomes meaningless. We're used to having something beyond something and hence boundaries. If the universe is closed then that doubly dissolves any boundaries since space curves back in on itself and there is no way to reach any real or apparent boundaries.

Well, wouldn't you know it - just checked my collection and that is the one I read (downloaded the pdf on 24 Nov) ...and I had a feeling that there was something incomplete about it, let me check... Ah, yes, origins of gravity & "what physical process the twisting and braiding of helons represents". But all-in-all it is quite an interesting theory. Come to think of it, I may have come accross it in one of your other/previous posts elsewhere here and that's why I read it. I will watch the presentation, just need to get some time up my sleeve first.

Martin, I have actually read a paper about preons and such. Cannot remember the detail, I will have a look again and refresh my memory, thanks for the links & the info. I am quite well versed with the St. Model however what I am looking for is a credible (non-cooky) explanation for the domination of matter in the U and perhaps a similar explanation of why CP symmetry violation occurs. Swaying off topic here a little - but it's all good.

Thanks Martin, I will source some of the proposed explanations for these observables, any idea of a good source?

Well, thank you Martin. Your post pretty much answers the questions I posed in post #176 in the 'Where does space end...' thread in this forum section that seems to have been overlooked and perhaps buried by the next poster. I should have posted it as a new topic I suppose. So we can still hold onto the hope that perhaps space is minutely curved and perhaps closed as long as we get a positive Omega value. Even though it is very close to 1, it CAN be said that the possibility of a closed ALMOST infinite universe still exists. Couldn't this minute curvature (translating to a larger curvature earlier on in the universe) be responsible for the reason we have mainly matter and not anti-matter as the norm? Couldn't this also be responsible for the CP symmetry violation?

My question is, is it sensical or non-sensical to use a photon reference frame to observe, using relativity, another photon? If it is sensical, then what is happening in terms of time dilation/length contraction in the following cases... Case A: 2 parallel photons travelling in the same direction separated by some arbitrary small distance say 1 mm. I understand that this would perhaps constitute the same frame of reference for both photons but, photon A would observe photon B to be travelling at c, is this not right? Lorentz transform would give us an undefined (division by 0) answer, is this correct? Case B: 2 minutely diverging photons (coming from same source - may even be entangled) eg. 1 mm apart after 1 second ie having travelled approx. 3x10^8 m Case C: 2 photons diverging at a 60 degree angle from the same source - may even be entangled. Case D: 2 parallel photons (in close proximity) travelling in opposite directions separated by some small distance say 1 mm. Is this the same as case A? Just need things cleared up by the experts. Thanks.

That clears it up. Till next time...thanks. Severian, if you have time, I have posed a question that you may want to have a look at in the Astronomy - 'Where does space end....' thread. It is sort of in reply to one of your posts...I hope you may be able to help.

Sorry, I had replied, and changed it since I had more time to think (told wife I'll be in bed in a mo). Ok, I suppose I can live with mass being uncertain although would this be the precision to which we have deduced the masses of particles to be ie. in the St. Model ? - these more or less (well most of) came from collider/accelerator experiments, from what I've sourced. Am I on the right track with this or am I still missing something? With regard to the photon momentum, with a photon having a certain speed c, that leaves E. This would be E=hf for a photon (or momentum p=h/lambda), which, in this instance would still leave us with uncertainty in either time (for frequency) or distance (for wavelength). I'm not trying to dispute the principle, just trying to understand why it is in terms of momentum. For mass particles if I've got the second paragraph above right then that explains it, but for the massless what then is the uncertain part? So what I am really asking is what are the fundamentally uncertain parts of the principle.

Heisenberg's uncertainty principle states that "The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa" My question is this, why do we say momentum is less/more precise when p=mv ? To elaborate a little, isn't the mass precisely known based on what particle is being measured and so it is just the velocity component that is less/more precise? Or even more to the point, isn't either distance travelled OR the time travelled less/more precise? I may be misled, but I was under the impression that the mass in the momentum equation is the rest mass and is invariant, so with that, why cloud the imprecision?

Fascinating, even with all the speculation. Today is the first time I came accross this thread and didn't realise it was so old and only just revived. Nevertheless, I checked out the WMAP data and it is quite compelling however, I do have some questions for the experts. Severian (or anyone else who is an expert on this), in one of your earlier posts on this subject you put a view accross that space is infinite but most importantly that it was created during the BB (with which I agree) and 'spread out' INSTANT(ANEOUS)LY. AFAIK, there is a consensus that gravitational waves (spacetime curvature) propagates at c, yes? If so, would this not imply that space itself would propagate from the BB at c if it was in fact created during this 'event' ? I am aware that this line of thought may be wrong but we must attribute spacetime to other components of the universe (namely energy) since it does have an intimate link - relativity. Also, one perhaps disturbing thing that I have noticed on the WMAP site (I found NASA's one) is although there is percentages of what the universe is made of (ie. matter, dark matter, dark energy) there is no mention of 'normal' energy that is NOT locked as ordinary matter! Surely the 'visible' universe is TEEMING with photons/neutrinos/bosons that would account, IMO, for some considerable portion of the universe curvature, or not? One other matter that may perhaps be beyond the scope of this thread. Although an experimental figure was obtained from WMAP that suggests space is flat rather than open or closed the figure is still positive. Could this not also imply that (keeping in mind that we do not completely and unequivocally understand space) space is just minutely curved overall (ie. not entirely flat) and that the universe still may be closed but ALMOST infinitely large. I know I am definitely wrong with this one and if so, could anyone point me in the right direction to explain why the brightest spots would have to be at least 1.5 degrees accross to make the universe closed AND why we couldn't possibly have gotten our timeline wrong and we're seeing the 'degrees accross' at an earlier stage post BB where the degrees accross were less? All this WMAP stuff seems to be built like a house of cards, one assumption after another, one dependant on another, that, if one little minute detail is just slightly off, makes the whole house collapse in a heap (or the physicists/astrophysicists are just standing up there supporting the cards so it doesn't fall into a heap). Why are we so certain about this whole space subject when we cannot even be certain that we have the understanding of space right.

For me it's not so much understanding space per se but more precisely understanding dimensionality. I know they're pretty much one and the same but 'space' comes with a bias - it is mostly imagined as 3d and unquestioned.On a fundamental level dimensionality is the effect of distance and not neccessarily 3d. Space is perceived as 3 dimensional but that does not mean that it is neccessarily so eg. string theory and its n-dimensional models. What if space was just the 'flip' side of energy (perhaps dark energy) without us even realising it. Some kind of total 'opposite'? Energy cannot be created or destroyed whereas space CAN (reference to the expanding space view among physicists). Combine all of space and energy in a ball and you have....nothing...our universe. Forgive....I'm in a speculation mode today for some reason...I think I'm coming down with something

JonM, on a purely speculative note consider this... You have a 'clump' (for the lack of a better word) of energy of n.quanta (consider this analogous to the beginnings of the Big Bang just so that we can see the 'birth' of space). There is no space between your quanta of energy - they're all superimposed. Say there is an event that causes 'instability' - the concept of direction perhaps? Something like I can point radially in any direction but nothing exists in those directions - not even space. The instability starts separating your quanta of energy. The dispersion (& separation) causes energy to 'create' the space between the quanta. And now as well as direction, dimensionality is 'born'. I just threw this together now quickly and as said, it is purely speculative - not a theory, unless I just described a 'version' of the Big Bang that someone else has already. It's a one possibility, however, it generates more questions than it answers.

I do get what you are saying Swansont. I'm agreeing with your questioning of the assumption of default flat space Perhaps I've clouded my response with a view from another angle. I think I was just trying to elaborate and question further this assumption (of default flat space). What makes you think I should be disagreeing? I am not disagreeing with relativity - I just believe there should have been a 3rd installment to it ie. SRT, GRT, URT - unfortunatelly Einstein stopped short (I think he ran out of gedankens ) My gedankens have picked up where he left off. And I also agree totally with your last post.

AFAIK, it has little to none to do with the uncertainty principle. As mentioned above, 0K would be the absence of energy - so what would we be achieving this 0K for? If you are trying to achieve it for a particle - you've lost the battle since a particle is a form of energy. On another note, it may theoretically be possible but that would manifest itself in whatever you're cooling 'disappearing' as its energy would be absorbed by whatever you're using to cool it but since a particle (non-massless) still has a fair bit of energy even at billionths of K this to me would seem quite impossible.

Exactly Swansont. The more I follow Einstein's logic, the more I see that it has been left unfinished. To me (at least), it seems that curvature is the norm and flat space is the anomaly. Afterall, we'd be hard pushed to find flat spacetime within our solar system. Flat spacetime would result from the superposition of equally opposite curvatures of spacetime eg. half-way between 2 planets of equal mass and in that space you would not fall (or feel the effects of gravity from either planet) to either planet - this too would be very difficult to detect as the mid-point would have to be precise. The assumption that spacetime is flat by default IS the fundamental flaw. It is a consensus, AFAIK, that spacetime emerged with the Big Bang and it is only logical that it was not flat as it emerged because of the high energies (& densities) in the primordial universe - so why is it assumed that it was flat. As far as I can gather if energy is the cause of spacetime curvature (and IMO the source of spacetime) there never was any flat space - just superpositions that momentarily resulted in flat space here and there. That's why I say that Einstein's work is unfinished - he also worked on the assumption that spacetime is flat by default. The correction of this fundamental flaw will undoubtedly, IMO, lead to new spacetime model(s)/geometric model(s) and eventually new physics. It is strange though, there seems to be a universal 'evolution' & shift among 'thinkers' (I don't want to isolate great findings - new thoughts only to physicists - it's a collective effort) to questioning the fundamental components of the universe - energy + spacetime. We pretty much have a good grasp of the former, but flaws about the latter stop us from unifying all that we know.

Actually, to be more correct, we assume that energy (predominantly locked as mass) curves spacetime OR gravity is the curvature of spacetime. Gravity is not the cause of spacetime curvature it is the resulting effect of it. Nevertheless, aether is a misleading term for space(-time) as Swansont has mentioned for the reasons given however I would beg to differ in that it is merely a mathematical construct (MC). If we do that, IMO, everything becomes just a mathematical construct. We know spacetime curvature exists (it has been observed many a time) just like for example the velocity of a particle exists. If we call spacetime curvature a MC then so is velocity. In my opinion, the way we have modelled space is an approximation to reality and as a result the way we use spacetime becomes a mathematical construct but in reality nothing is a mathematical construct because all that we observe 'exists' - even space. ...I'd say that all it means is that there are many ways to interpret fnarb but regardless, we are modelling something - that something does exist. How approximate to reality that is depends on how well the model describes everything that we can & will observe. Now, we know that neither relativity or QM or any other theory out there describes everything that we observe completely. Holes are abound. More precisely, to describe what we observe we often result to using different models of space. Euclidian space, Minkowski space, etc. and now some exotic forms of space in the various forms of string theory - they're still trying to model something that is real.

I too have limited knowledge of quantum gravity but with the proposal above when it comes to warped spacetime interacting with the other mass, warped spacetime would 'somehow' have to create gravitons to interact again with the particles of the mass that is being affected. Although again pure speculation (until we don't observe gravitons no matter how powerfull a collider we create), I would lean towards Transdecimal's proposal that there really are no gravitons and relativity with its warped spacetime explanation (with no particles as mediators) of gravity is all there is to it. Well, at least on the surface anyway. As I keep on hinting, and some may get annoyed with it, there is something fundamental we are missing. And it is not anything new, just a more 'realistic' interpretation of space (dimensionality) than what we have become accustomed to over the millenia. On a macroscopic level, sure we perceive space as 3 dimensional but there certainly are some odd phenomena on a quantum level that although overlooked, to me, would suggest that our view of dimensionality is flawed. And just to answer the original topic question, gravity propagates at the speed of light c as I think Swansont has already mentioned.