The Inhomogeneous Expansion of Space by Roger H Pink

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

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

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

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

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

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

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

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 curving, space varies in density. Rather than the force of Gravity being due to curvature of space, I think one could argue that gravity is denser space. If you think carefully about it, knowing what we do about index of refraction and treating matter as de Broglie waves, it all works out fine mathematically (as far as I know). It takes people a while to swallow what I just said so I will avoid drowning you in details. I'll just summarize, but first here is an example from classical physics to show that this isn't completely out of left field (density and curvature mathematical equivalence)

Ex. GRIN Lenses- Gradient Index lenses produce the same effect as curved lenses by gradually varying Index of Refraction. GRIN Lenses are found in the optics industry all over the place.

So you see, this idea of density and curvature being two ways of doing the same thing is actually a well established (old) idea in other areas (optics).

So that said, if it's denser, why? Maybe space feels gravity and "piles up" around energy density causing it to become denser. If space experiences and exerts gravitational pull, and is not homogeneous but rather is denser around higher energy densities (within galaxies as compared to the voids surrounding them), then it stands to reason that the slightly denser space found within the galaxy might have a net gravitational effect located at the galaxy's center of mass. Thus the galaxy appears to have more mass than we see which we interpret as dark matter.

Of course large voids would have the opposite effect. Since they are less dense, they would feel and exert less gravity leading to faster than expected expansion (dark energy)

Its hard in so small a space to give the tons of examples I have thought out in order to come up with such an unusual interpretation (not of dark matter and dark energy but rather of density vs curvature), so I understand if you dismiss the idea, but I really do believe it should be acceptable, without changing Relativity in any way, to think of it as density of space rather than curvature.

Anyway, that's that.

Oh, one neat way I think about this "density of space" thing is picturing orbits, which I do with de Broglie waves and total internal reflection. It works if you remember that redshifting a de Broglie wave means the object has less momentum and think of gravity as density of space rather than curvature of space.

(To be clear, I'm saying either the curvature or density interpretation is correct since it doesn't change the mathematics underneath. I just think using the density interpret makes understanding dark energy and dark matter better.

Anyway, that's what I mean by eccentric.

Best Regards,

Roger

I wrote "total internal reflection" above with regards to de Broglie Waves but really what I meant was refraction and critical angles.

Roger

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 [math]R_1 [/math] and [math]N_1 [/math] was the quantity of people which gave you ratings. Then you have [math]S_1=R_1 N_1 [/math] of points. After it anyone give you [math]dS [/math] of points so you have [math]S_2=S_1+ dS [/math] of points and [math]N_2=N_1+1 [/math] is the common quantity of the people which gave you ratings. At the same time you will have [math]S_2=R_2 N_2 [/math] of points. From here, if you want to be R2 > R1 there must be: [math]S_2/ N_2>S_1/ N_1 [/math] or [math] (S_1+ dS) / (N_1+1) >S_1/ N_1 [/math] or [math] dS >S_1/ N_1 =R_1[/math] In other words if you want to increase rating of anyone you must give him more points [math]dS [/math] then the participant`s rating [math]R_1 [/math] 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

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