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RECENT POSTS IN THIS TOPIC

Charles Weber: on 11/1/12 at 0:18am UTC, wrote Dear Rojer Pink, In portrayals of the Universe astronomers present...

Roger: on 10/4/12 at 12:16pm UTC, wrote I think it's enough that they provide us a forum to express our ideas. It...

Sergey Fedosin: on 10/4/12 at 6:55am UTC, wrote If you do not understand why your rating dropped down. As I found ratings...

Roger: on 10/3/12 at 1:53am UTC, wrote I wrote "total internal reflection" above with regards to de Broglie Waves...

Roger: on 10/2/12 at 20:54pm UTC, wrote I've thought about this before (Dark Energy and Dark Matter). I think to...

Roger: on 10/2/12 at 20:00pm UTC, wrote Sergey, Thanks for the endorsement, but really just getting the chance to...

Roger: on 10/2/12 at 19:58pm UTC, wrote All of science consists of theoretical ideas that can't be proven...

Sergey Fedosin: on 10/2/12 at 11:54am UTC, wrote After studying about 250 essays in this contest, I realize now, how can I...


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FQXi FORUM
July 18, 2019

CATEGORY: Questioning the Foundations Essay Contest (2012) [back]
TOPIC: The Inhomogeneous Expansion of Space by Roger H Pink [refresh]
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Author Roger H Pink wrote on Aug. 20, 2012 @ 12:07 GMT
Essay Abstract

It is generally accepted that the metric expansion of space is homogeneous, or at the very least any inhomogeneity in the expansion rate deviating from the Hubble constant is negligible. I contend that the expansion rate varies and is actually non-negligible at very small scales in the presence of very large localized energy-densities (large energy-density inhomogeneities).

Author Bio

I am someone who is reluctant to submit his thoughts here for fear of being labelled an eccentric, but hopefully this is truly an open environment where the worst that can happen is to be simply shrugged off (I'm totally ok with that outcome).

Download Essay PDF File

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Peter Jackson wrote on Aug. 20, 2012 @ 16:52 GMT
Roger.

Inhomogeneous expansion seems almost mainstream compared to some of our thoughts here! No, you're certainly not eccentric.

Your thesis is consistent with mine, though covered more in my previous essay than here, and derived from CMBR ansotropic flow on the model of a helical quasar jet with collimation, decelleration and local Navier-Stokes turbulence.

Short but sweet essay. You seem un entrenched by indoctrination so I hope you may read my essay to see if you can find the jewels screened by assumptions to most (or by the theatrical top metaphorical layer)

Johan Masreliez (Google him) also has theories similar in ways to both yours and mine. Of course the big question still is, is something 'expanding', or are small things getting further apart.??

Best wishes with all your ventures.

Peter

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Roger replied on Aug. 21, 2012 @ 12:15 GMT
Peter,

Thanks for your kind support. Having read your essay now, and also reviewed Johan Masreliez theries as you suggested, I'm concerned I might not have been clear in what I was trying to say in my essay. In no way am I advocating a reexamination of General Relativity, nor any sort of reinterpretation. What I'm saying is basically this:

The FLRW metric assumes a homogeneous energy-momentum tensor and not surprisingly predicts a homogeneous expansion of space. The assumption was made because it's a much easier problem to solve. At the largest scale the Universe looks homogeneous, thus it does a decent job modeling the broad strokes of how the universe behaves over time (Hubble expansion, big bang). However, only the broad strokes. There is all kinds of problems that it can't seem to explain that we simply call "dark" (dark matter, dark energy, dark flow).

I believe GR is fine, it's just that the assumption of a homogeneous energy-momentum tensor in the FLRW metric is probably only valid as a first approximation. I suspect that if we were to use an inhomogeneous energy-momentum tensor and somehow solve Einstein's Equations we would find non-trivial inhomogeneous spacetime expansion. I suspect more specifically we would find that the larger the local energy-density gradient, the faster local spacetime expands. I think if this turned out to be true, then like any good theory, it would default to the fist approximation on the largest scales (ie the FLRW metric; homogeneous spacetime expansion).

I also take the leap in my essay to say "If spacetime expands fast enough in the presence of a large energy-density gradient, maybe it could be the underlying mechanism that causes the uncertainty principle and all of it's consequences." This is a big leap, and I don't mind people not accepting it, but to me it seems logical, given what the uncertainty principle seems to say.

Anyway, I appreciate your taking the time to read my essay and commenting. I think this is a great thing FQXI is doing.

Best Regards,

Roger

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Diane Richards wrote on Aug. 20, 2012 @ 16:57 GMT
Short and sweet! I love it. Certainly at tiny scales approaching points, Ratios of surface-to-volume (as a tiny particle) are unbounded, i.e. a source of infinite energy

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Roger replied on Aug. 21, 2012 @ 12:35 GMT
Hi Diane,

Thanks for your comments. Yes, it's true that in spacetime that doesn't expand, the infinities that come about due to point masses are a problem. However, if spacetime expands faster in the presence of larger energy-density gradients (local inhomogeneous expansion in the presence of larger local energy-density inhomogeneities), it essentially prevents the point like infinite energy problem from occurring, basically because the more pointlike an energy-density becomes, the more furiously space-time tries to pull it apart.

Since the only thing preventing matter from being ripped apart by spacetime expansion are forces (strong force, electromagnetic force, gravity), a sort of equilibrium is reached for each force where the spacetime expansion is exactly offset by the force. So you get a situation where energy density is neither pointlike (prevented by spatial expansion) nor homogeneous (prevented by forces which holds the matter together).

Another way to see that spatial expansion reduces the energy of matter traveling through space is to thing of matter in terms of it's de Broglie wavelength. expanding spacetime redshifts the de Broglie wavelength just as it does electromagnetic waves. And just as with electromagnetic waves, a redshifted de Broglie wave has less energy. So that's another way of seeing how spatial expansion resists pointlike energy from occurring (point-like energy would be an infinitely small de Broglie wavelength).

Anyway, I'm sorry I'm going on and on here. It seems like I'm trying to make up for making my essay so short.

Best Regards,

Roger

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Sergey G Fedosin wrote on Sep. 21, 2012 @ 11:35 GMT
Dear Roger,

It seems the Big Bang is a theoretical idea which can not be proved. It is known that expansion of space with time again is mathematical idea. But where is the physics here? What is your opinion why physicists do not choose other option of silent Universe, in which is possible to explain cosmological effects too?

Sergey Fedosin

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Roger replied on Oct. 2, 2012 @ 19:58 GMT
All of science consists of theoretical ideas that can't be proven (absolutely). In the end we use experiment and observation to determine if a theory is probable. There is a lot of real world evidence for the Big Bang (galaxy redshift dependent on distance, CMB, etc.)

One of the dangers addressed early in the development of science, but often forgotten, is that Theory then Data is not the same as Data then Theory. The reason theories such as "Silent Universe" or "Steady State" don't get much traction is they are theories fit to data, not theories confirmed by data. If either of those alternate theories made a prediction that contradicted the current Big Bang Model, and observation or experiment showed that prediction to be true, then I think you would see much larger acceptance, or at least conversation.

Simply developing a theory that fits the data after the fact isn't science.

At least that's my opinion on the subject, a lesson I think the world of sports statisticians need to learn ASAP before they make ESPN unwatchable for me.

Best Regards,

Roger

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Member Benjamin F. Dribus wrote on Sep. 27, 2012 @ 15:00 GMT
Dear Roger,

I think this is an interesting idea. It's certainly worth considering. We know (or think we know) that the expansion of the universe is related to the energy density, so it seems reasonable to hypothesize that this is in fact a local effect; i.e., that the expansion varies according to the amount of matter-energy present, just as you propose.

Something that might be worth thinking about is how this would apply to "dark matter" versus "dark energy." Dark energy is usually viewed as being directly related to the expansion of the universe (some equate dark energy to the cosmological constant), while dark matter is generally viewed as being "actual matter," just matter we can't see. Anyway, the two "dark entities" seem to have opposite effects; dark matter "makes gravity appear stronger," while dark energy "makes gravity appear weaker." Since dark matter is much more local than dark energy, it might be interesting to try to explain the difference along the lines you suggest.

As for being "eccentric," how about the suggestion that spacetime dimension may vary locally too? I make that suggestion at the end of my essay here.

Bold ideas are what a form like this should be about. I enjoyed reading yours! Take care,

Ben Dribus

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Roger replied on Oct. 2, 2012 @ 20:54 GMT
I've thought about this before (Dark Energy and Dark Matter). I think to explain how I think they might be related I should confess something about how I view relativity.

I think General Relativity is absolutely correct, but I think it's interpretation (curved space) may be just one of two ways of viewing it, or at least there may be an equally correct interpretation, namely rather than...

view entire post


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Roger replied on Oct. 3, 2012 @ 01:53 GMT
I wrote "total internal reflection" above with regards to de Broglie Waves but really what I meant was refraction and critical angles.

Roger

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Georgina Parry wrote on Sep. 30, 2012 @ 23:26 GMT
Dear Roger H Pink,

You pose an interesting question about how the expansion of space is to be regarded. Your point about ignoring what happens when space expands is something John Merryman has also mentioned a number of times on FQXi blogs discussion threads. A worthwhile contemplation. Your questioning the idea of homogeneous expansion is certainly also worthwhile.

I don't think the material universe is expanding but that assumed expansion is an error. Produced from misinterpreting the effect of the continual motion of the Earth along its Object universal trajectory, upon data receipt. Anything affecting the foundational environment through which EM data is transmitted will (most likely) affect the output fabricated from the data, giving a different fabricated/perceived reality and non homogeneity of perceived expansion. It is IMHO necessary to differentiate between the fabrication produced from received EM and the material universe. You may find that an interesting idea or maybe a bit eccentric. Either is fine.

I don't think you should be reluctant to put forward ideas. Ideas do not always have to be the final word and entirely correct in order to be useful. They can be a foundation on which to build, a springboard leading to something entirely different or a signpost giving an interesting direction to explore. The ideas that are petrified, put on a pedestal and revered may be the least useful.I wonder why you did not expand your interesting discussion into a longer essay which could have then fared better in the competition. Kind regards Georgina

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Sergey G Fedosin wrote on Oct. 2, 2012 @ 11:54 GMT
After studying about 250 essays in this contest, I realize now, how can I assess the level of each submitted work. Accordingly, I rated some essays, including yours.

Cood luck.

Sergey Fedosin

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Roger replied on Oct. 2, 2012 @ 20:00 GMT
Sergey,

Thanks for the endorsement, but really just getting the chance to throw this idea in the mix with the others was enough.

Best Regards,

Roger

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Sergey G Fedosin wrote on Oct. 4, 2012 @ 06:55 GMT
If you do not understand why your rating dropped down. As I found ratings in the contest are calculated in the next way. Suppose your rating is
and
was the quantity of people which gave you ratings. Then you have
of points. After it anyone give you
of points so you have
of points and
is the common quantity of the people which gave you ratings. At the same time you will have
of points. From here, if you want to be R2 > R1 there must be:
or
or
In other words if you want to increase rating of anyone you must give him more points
then the participant`s rating
was at the moment you rated him. From here it is seen that in the contest are special rules for ratings. And from here there are misunderstanding of some participants what is happened with their ratings. Moreover since community ratings are hided some participants do not sure how increase ratings of others and gives them maximum 10 points. But in the case the scale from 1 to 10 of points do not work, and some essays are overestimated and some essays are drop down. In my opinion it is a bad problem with this Contest rating process. I hope the FQXI community will change the rating process.

Sergey Fedosin

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Roger replied on Oct. 4, 2012 @ 12:16 GMT
I think it's enough that they provide us a forum to express our ideas. It is only natural that everyone won't be happy with the rating process.

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Charles Weber wrote on Nov. 1, 2012 @ 00:18 GMT
Dear Rojer Pink,

In portrayals of the Universe astronomers present as if the big bang and expanding galaxies were an established fact. But actually there is no evidence that the we are at the center of the Universe and the galaxies are all moving away from us other than the assumption that the cosmological red shift is a Doppler shift. There is a discussion of other possible causes of the red shift in http://charles_w.tripod.com/red.html . My own view is that the red shift is due to an interaction of the photons with masses passed in space. If light actually is degraded by the ether itself, It should prove impossible to establish the cause by experiment, because the affect would be so tiny.

Astronomers speak of a "young Universe". It was, of course, younger than it is now when distant stars shone. However, there is no chance at all that the Universe was as young as astronomers say when the light from those distant stars was created even if the big bang hypothesis were valid. It took the light over 13 billion years to arrive here, so it is obvious that the atoms emitting it took well over 13 billion years to get out there even given a big bang. It does not make any difference if the atoms traveled out there from a spot near here or the ether is expanding, well over 13 billion years would have had to go by, so by now the Universe could be over 30 billion years old even in the unlikely event that there was a big bang.

You may also find interesting a hypothesis that the characteristics of quasars arise because of refractive lensing by gases near a huge mass inside the quasar of the light from an opposite jet in http://charles_w.tripod.com/quasar.html .

Sincerely, Charles Weber

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