pantheory

I believe Chris said "From what I've read most cosmologists agree that the requiste pre-inflationary conditions are high temperature and (to resolve the "flatness problem") an almost perfectly uniform density ."

 

I think this is not quite right. I believe the almost perfectly uniform density of the universe is a result of inflation, not a pre-inflationary condition.

(bold added)

According to BB models in general, the observable universe should not be uniform in density. For observing most of it we must look back in time. In an expanding universe model (expanding distances between galaxies) the universe should have been eight times more dense 7 billion years ago (the volume of a sphere pi x r^3). As you said the universe appears to be of a uniform density no matter how far back in time we look, which I also think is what we have observed. The direct implication, I believe, is that the universe may not be expanding at all, which would also explain contradictions of entropy as questioned by the O.P. If so there would be a different reason for the observed redshifts.

There does seem to be a contradiction IMO concerning continuously increasing entropy, the standard model, and what is being observed. If the universe is not expanding then gravity could seemingly keep pace with entropy to accordingly find the equilibrium that we may be now observing.

@Pantheory

 

You are terribly wrong.

It is not Ocamm's razor but Occam's razor.

 

The rest of your post makes some sense.

Thanks for the correction. I've seen Occam spelled a number of different ways but for that posting maybe I just made up my own version of the spelling, or maybe my right hand just did not know what my left brain was doing

The "modern age problem" (old high redshift objects) is a current area of research and is being tackled by models of dark energy. I would say that such old redshift objects are a great way of testing models of dark energy, rather than something inconsistent with theory.

I have not heard of the idea of old appearing galaxies being used to test models of dark energy. Thanks, I will have to research it. I believe dark energy and dark matter are not real but can be explained away simply by "slight justifiable changes" of formulations concerning the Hubble formula and GR.

I agree Chris,

Your quotation seems like a good summary according to the standard model perspective. I showed my skepticism because I am skeptical concerning the standard L CDM model or any BB version for that matter. The OP question involves increasing entropy over time and is based, I believe, upon theory alone and has no observational basis which I believe adds to his and others questioning of such cosmological interpretations which require increasing entropy over time.

regards Forrest

The great thing about science is we don't have to rely on belief. We want a testable model. That's the price of admission.

I have a testable alternative cosmological model that involves aether. Do you want me to start a thread here? I would like somebody to request it so that there might be at least a little dialog to it

teh,

Aligned with the eather means moving with the eather thru space. Thus in my testable model when the spaceship in orbit is made to free fall an inertial frame exists which is not aligned with the eather & should not give a zero result.

(your quote)

Good, that's what I thought you meant. In some versions of aether theory including my own, you could say that the background aether is in motion as compared to a defined reference frame of space confined by matter, such as defined within a spiral galaxy for instance. The theoretical aether field particles might contain dark matter, Higg's particles, gravitons, quantum foam, and/ or countless other theoretical possibilities. It might move in a linear fashion, it may have fluid dynamics, or vortex mechanics, or other possible dynamics at the galactic or smaller scales if it exists.

Kepler finding: This would seem to be it if it was recent:

April -2011

Time Magazine article and related blog

http://www.time.com/time/health/article/0,8599,2065049,00.html

The Hubble Law, maybe more accurately described as the Hubble formula, seems to be totally Euclidean as you suggest. The B factor in this formula is the only thing complicated about it. It transforms redshifts into distances and is based upon Lorentz Transforms of moving time frames away from the observer. Although simple in form, this factor was quite difficult to derive.

The Dark Energy hypothesis is based upon distance calculations using the Hubble formula. If it is off in its formulation by as little as 11%, then Dark Energy would not be needed to explain type 1a supernova observations and maybe not anything else.

The Hubble formula must necessarily be flat since Riemann geometry and GR are not part of its formulation. The Hubble formula relates to a straight-line path of EM radiation even though we know that galaxies are not in straight line paths as we observe them, due to the effects of intervening gravity, so that at least some galaxies would be accordingly at closer distances than what their redshifts indicate.

ajb,

The evidence for the Lambda CDM model (with inflation) seems overwhelming. I cannot see that any theories that are greatly different to this could be taken very seriously.

Any attempts to model physics at or very near the classical singularity must evolve into the Lambda CDM model or something very close. For example the Ekpyrotic Universe model contains the Lambda CDM model after the initial collision of the branes. Detailed studies of the CMBR should be able to distinguish inflation and Ekpyrotic models, but you would have to do a literature search to find out details and the current status. (I believe the inflation model seems to agree with observation extremely well.)

I think there is much evidence that is contrary to the standard model. One of the big problems, I believe, concerns the observed density of the universe. Looking back half the age that the universe is thought to be, about 7 billion years ago at a redshift of ~1.75, the universe would have been denser according to the expanding universe model and the Big Bang, not just by a little but by a factor of 8. There is no evidence that I know of that the universe was ever more dense in the past concerning the density of observable galaxies in that time frame. The second major problem, I think, is that there appears to be very old appearing galaxies as well as large elliptical galaxies as far back as we can presently observe. In the BB model, old galaxies (the age of the Milky Way) could not exist at these distances. Another seeming problem is that galaxies accordingly become large by merging with other galaxies. We know that this happens but is this the primary reason galaxies become large? There seems to be evidence that galaxies grow from the inside out and that galactic type black hole entities might come first. I have a collection of such papers that at least in some ways seem to contradict the Lambda CDM model. Here are a few such links that seem to challenge present-day cosmology concerning the age of the universe.

http://www.scienceda...50310102001.htm

http://www.astronomy...f1-9b749d7f8f56

http://outreach.jach...008b/index.html

http://www.cfa.harva...8/pr200821.html

http://www.astronomy...b6-7da4afb9ee0c

Of course there are many observations that are also asserted to support the standard model. I think interpretations are a big part of all observations which stretch the limits of what can presently be observed.

Only nature can really decide this. If a very conceptually and mathematically complicated theory agrees with nature to some very high accuracy then one will be forced to accept this theory as a good theory. Occam's razor would only help if one has two or more theories that completely agree with each other and nature, up to the domains of applicability etc. Even then, it may not be clear which theory is really simpler.

(bold added)

I think some alternative theory's/ models are far simpler than the L CDM (Inflation) model, being different both conceptually and mathematically. Ocamm's razor generally states that the simpler model is probably the better model, all else being equal. The big question always concerns the latter contention, "all else being equal. " I will present such a alternative theory in the Speculation forum if you are interested, since I realize that you are well educated on this subject and could add much to such a discussion.

I personally expect that if a model ever replaces the standard model, that such a model will be quite different and also simpler than the L CDM model.

I ME,

So what about the rest of the universe we cannot see? How can we know whether the entire universe, whether finite or infinite, is indeed flat (net zero spacetime curvature)?

We can never observe the entire universe according to almost every possible cosmology mainstream or otherwise, therefore as you suggest, we could never know for sure whether the universe as a whole is flat or not. Observation presently suggests that the universe is flat, but Einstein's cosmological equations without a cosmological constant imply that the universe is not flat. With this constant added along with the Inflation hypothesis, the universe seemingly could be flat and open.

.

I ME,

OK, so my question is: where did this inflation come from? And what was the entropy of the universe before inflation? And does this violate the second law of thermodynamic? Unfortunately, I don't think anyone has an answer for these questions outside of speculation. Perhaps a new quantum gravity theory will shed more light on this issue.

There are hypothesis that address these questions; some might be considered mainstream and others not. Non-mainstream theorists also consider the mainstream to be nothing more than speculation. There may be a true answer for such questions but maybe not within the mainstream arena of speculation. Brian Green's applicable speculations are considered mainstream hypothesis.

Airbrush,

I really like these comments. Before the BB there was potential for BB. Some kind of "internal potential energy" that caused a rapid expansion of stuff, from a region of undeterminable size....

Thanks Airbrush. You would not say "before the BB," instead you might say at the beginning of time the BB entity had the potential energy to "bang." According to the standard model, both time and space were created as the BB progressed so there would be no such thing as before the big bang. Some alternative mainstream versions believe the BB was caused by a fluctuation in the Zero Point Field. In such alternative models there was a time before the BB but not according to the standard version. There are many BB versions with no consensus concerning a beginning big bang entity. There are also many other cosmological models that are generally considered to be either non-mainstream, or no longer are considered mainstream.

ajb,

This is the usual answer based on classical general relativity and standard cosmology. However, people applying models of quantum gravity to the early Universe have pointed towards pre-big bang cosmology. It sounds crazy, but people publish papers on this.

 

The most truthful answer here is that is is simply not known what caused the big bang or what was before the big bang, or even if before has a real meaning. We understand the physics of the Universe close to the "birth of the Universe", but our understanding of the physics at or very close to the "birth" is poor. Simply put one would expect quantum gravity to play a significant role and right now we do not have a great grip on quantum gravity.

 

One general feature we expect is that quantum effects will regulate the initial singularity of the classical theory. You can argue this by suggesting that space-time at or near the Planck length is noncommutative; something like the phase space in quantum mechanics and is thus dived into "Planck cells".

 

Right now string and brane cosmology is really still in its infancy, as is loop quantum cosmology.

Yeah, you are right. Papers get published because it is still considered an open question. Trying to get a non-BB paper published is a more difficult talk, and often must be done through alternative publishers so that they generally never get read, and remain unknown to the mainstream.

As you suggest string theory has not played itself out yet but it is more difficult to get some of these papers published now. Membrane cosmology is directly related to string theory. Loop quantum cosmology involve the implications of loop quantum gravity which for one thing has been an attempt at explaining the Inflation hypothesis. There is still a lot of mainstream room for publications concerning these subjects as you suggest. I don't think Ocamm's razor could apply to any of these models mentioned as being more preferable than another since none are simpler than others concerning their formulations.

My expectation is that the "correct" answers will be more obvious/ simpler and in compliance with Occam's razor.

nernico,

What created Big Bang? What created the thing that created Big Bang?

These are simple questions with very simple answers generally independent of what cosmological model you adhere to. According to the BB model the BB had an internal potential energy that created the bang. Accordingly there is no such thing as something before that. Although accordingly time is of a finite duration and accordingly there was no such thing as before the big bang since it would be a logical contradiction. I would be like asking what change came before the first change ( a child-like question). Please note that this explanation applies to any cosmological model concerning a finite period of time, not just the standard model.

And why is there something rather than nothing?

This is the question Stephen Hawking asked at the end of his book. The answer again is very simple if you will believe this answer Do you believe in flying purple people eaters? No. Why not? because they have never been observed. O.K. good answer. Flying purple people eaters, just like nothingness, is not a possible state of reality, nor was it ever a possible reality. Nothingness just like any other imaginary reality like one including flying purple people eaters is not one of those possible states. -- do you understand? if not keep your questions flying.

csmythe3025,

....I'm thinking that the entropy of a closed system (in this case, the universe) increases over time not only due to the flow of heat from warmer regions to cooler regions,

... but also due to the flow of mass from areas of higher gravitational potential energy to areas of lower gravitational energy.

I agree that your understanding of the flow of mass is in line with the meaning of entropy concerning gravitational flow but not what has happened concerning the evolution of the universe in my opinion, no matter what cosmological model one adheres to.

I'll limit my reply to this observation for now. I'll have to think about this for a while. Perhaps a more knowledgeable member can respond more completely.

That's why I like talking with you Chris. Logic is an important constituent in your postings. To me logic trumps everything else providing the logic is good enough A "more knowledgeable member" might provide better insight for some, but for me logic alone is gold such as I perceive the best of your logic is You have my ear.

csmythe3025,

Good over-all answer Chris. Even with my best mainstream-perspective "insights" I don't believe I could have done very well concerning a non-frivolous explanation By being a little flippant in my posting I was trying to show how the second law of thermodynamics does not seem to fit with the standard model of cosmology, in my opinion. And it appears the O.P. also has a problem with a connection. Gravity for one thing and evolution for another, seem to work contrary to the second law.

If they are not congruent/ consistent with each other, implying maybe one is correct and the other is wrong, which one would you want to bet on?

`if your theory is ... against the second law of thermodynamics ... there is nothing for it but to collapse in deepest humiliation' (Eddington)

I think most realize that there are no guarantees that either the standard model of cosmology is correct, or that the second law of thermodynamics (including increasing entropy) should apply in its present wording, to the universe as a whole.

Entropy: A thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work.

In the universe entropy accordingly increases with time. Entropy: Lack of order or predictability; gradual decline into disorder.

From the extreme order following the Big Bang to the extreme homogeneity and disorder of galaxies, clusters, life, humans, etc. disorder today. The theory concerning increasing entropy in the universe over time makes total sense to me, NOT!

Here are a few links that I found concerning/ discussing speciation.

http://www.talkorigi...speciation.html

http://answers.yahoo...28124045AAJzK57

http://www.nature.co...e081002-01.html

http://www.nature.co...l/6800840a.html

One of the examples concerns a type of lake fish, I have heard of before. There are also other examples that I am aware of but could not find links in the brief time that I researched it. Evolution like other theory have theoretical variations to it and as you understand much of it is speculative but the general principles of natural selection I believe are beyond question in that I would bet my house (no mortgage) against a six pack (when I am thirsty ) that this theory of natural selection is generally correct.

Widdekind,

...Thus, an unexplained 'dark energy was activated at about z=1' scenario is noticeably less compatible, with the comparison, between the 2MRS vs. HDF/HUDF sky surveys....

I think you need to calculate backwards, the reason being that binned data of type 1a supernova indicate a change concerning apparent brightness of supernova at about z=.6 . At redshifts smaller than this, supernova appear to be dimmer than expected on an average (binned data). For redshifts greater than z=.6, supernova appear to be brighter than expected with increasing brightness as distance increases. So calculations, I believe, should adjust for a conclusion that dark energy (DE) was activated at redshifts z~.6, and continuing to the present time. As for me, I simply believe the Hubble formula for distances needs a wee tweak. I made changes myself to the Hubble formula that seem to compensate for the divergence. I think this is a much simpler explanation for variations of supernova data (about 11% max. adjustment is needed based upon my calcs) rather than the DE hypothesis implying cosmological reformulation.

You also may wish to consider that according to the DE proposal there was never a Hubble Constant as in your formulation, i.e. no constant rate of expansion. Before z=.6 the rate of expansion accordingly increases as you go forward in time to the present day. Before z=.6 the rate of expansion accordingly increases as you go backward in time, the minimum expansion rate being at about z=.6 according to this hypothesis.

gillian andrews,

Not quite sure where spacecraft come into the model? But the reason the model says that currently there is no short-cut is because SO FAR nobody has found real wormholes. If they do then you might be able to take a straight line from cluster to cluster instead of having to follow the path of light which in the model is traveling according to metric expansion along the curves.

Mentioning space craft was for the purpose of indicating that in a flat, Euclidean universe (three dimensional with time) you can always go straight in any direction that you want to any place that you want provided that you have enough fuel to follow a totally straight path without some kind of circular path to your destiny which is the more fuel efficient way. The flat universe model, which present evidence supports, if continuous would seemingly preclude possibilities of other dimensions, parallel dimensions, or wormholes. What you see is what you get, a generally simple universe model. If you can observe a location you could accordingly fly in a straight line toward its approximated location upon your arrival. This assumes that you have unlimited fuel and are able to compensate for the intervening forces of gravity and the effects of an evolving universe in that neighborhood, without altering your course.

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Widdekind,

..... even 'recent' SNIa are far too faint, and hence far too far away for any kind of Cosmology ...... (...to explain without using dark energy)

Even though most have never heard of it, there is a cosmology that requires / and predicts type 1a supernova to have the observed brightnesses without dark energy being needed or implied. It is a cosmology that requires a somewhat different Hubble formula to calculate distances and brightnesses. Based upon these different distance and brightness calculations, a straight line concerning supernova vs. distance is drawn implying no need, use, or existence of dark energy. Upon your request I can provide you links to this cosmology/ model but a discussion, if desired, must take place in the speculation forum since it is not a mainstream cosmology.

Sounds like a reasonable explanation to me I have not studied 1a normal light profiles much but have studied binned data extensively concerning the asserted dark energy hypothesis and as a result reformulated the Hubble formula attempting to otherwise explain 1a observations as standard candles without needing dark energy (by using another cosmological model).

Photons are particles in a field around the earth, moving with the earth thru space, enclosed in the sun's ether & rotating round the sun yearly.

Responsible for gravity inertia. Electrostatic & magnetic forces are distortions in the ether at right angles to each other, light being oscillations between them.

Satisfies Michelson-Morley & Sagnac experiments. Relativity works if the inertial frame is aligned with the ether.

I like the general idea of what you have posted but have the following comments:

Relativity works if the inertial frame is aligned with the ether.

This sentence does not make sense to me even though I think the above has at least some validity. The calculations of Lorenz Transforms and Special Relativity work in all inertial time frames concerning calculations, not just aligned frames. Inertial time frames that are co-moving with the aether accordingly have no "real" motion at all. What does "aligned with the aether" mean to you?

I think that by saying "there is no evidence on either side, its all speculation" is an incorrect statement concerning evolution. You might say there is no proof of the theory of evolution but there is almost countless evidence now that supports this theory, and its subset natural selection.

Swansont wrote:

"Clocks "tick" at different rates in different inertial circumstances, as proven by many experiments. does not specifically address the issue of whether it's a mechanical issue of the clock. But this issue has not been ignored — different types of clocks have been tested, and they all show the time dilation effect. So we conclude that the timing changes are due to the effects of relativity. "

 

I'm trying to get at the ontolology of "time," like, what is "it" besides event duration between designated instants?

I know that our most sophisticated clocks show what has come to be known as "time dilation," but how is that different than, as above, the fact that they "keep time" differently (slow down or speed up) in different inertial environment

 

Clocks keeping time at different rates is a different issue than asserting that "time itself" is an actual medium/entity which differs in each and every local inertia situation.

I hope I'm making this distinction clearly. The ontology of time is a deep subject and relativity does not have a lock on time as a malleable medium in an of "itself," which clocks simply measure.

 

Even the debate about a "global time structure" shed light on the assumption of relativity that local inertial frames of reference are the end all of the nature of time, space and the universe.

BTW, I am not advocating that time is a "structure" but more like this: It is now everywhere (ongoing, perpetually), and time is an artifact of measurement, i.e., the duration of a given event between two designated instants.

 

What say you?

Respectfully,

Owl

I don't think that most concepts in Physics hit the mark concerning time. Such ideas such as time is a measurable period, or time is a continuum that lacks spatial dimensions -- do not inspire understandings of time in my opinion.

More broadly there are primarily two schools in philosophy concerning understandings of time which inter-relate to some definitions of it in science: One is called "absolutist" theory which regards time as a kind of container within which the universe exists and changes take place, and believe that its existence and properties are independent of the physical universe. According to the rival "relationist" theory, time is nothing over and above change in the physical universe. Relationist theory is the only logical definition, according to my own model and definition.

I think the O.P. (Owl) has a good understanding of what time is by saying "....the duration of a given event between two designated instants." I think this generally hits the nail on the head. Time is an interval of change according to my definition. The two key words accordingly are "change" and "interval." The concept involved would be: what would be the meaning of time if no changes of any kind took place. Time dilation occurs at both the macro and micro world levels as explained and calculated by Lorenz Transforms as in Special Relativity. A logical explanation I think is that time dilation is the result of apposing/ moving against the gravitational field which contains the entity experiencing time dilation as compared to objects which have no motion relative to their gravitational field, and which have the least time dilation. I believe time dilation is based upon the resistance of gravity which slows particle, atomic, and molecular decay and internal changes which can be measured relative to "stationary" material within the same gravitational position of the field.

I also like his use of the word "instants" in his definition. I chose the words "time frames" (as in photographs) for the same meaning as his.

between3and26characterslon,

Is it not the case that in TBB model the early stages of the universe were too hot for matter to form (?) You would then have space but no mass. If so my question would be did gravity exist before mass and was this the inflationary period (?)

This is a very good question. Again I don't think there is a mainstream consensus concerning an answer. One faction might say that the outward forces of pure energy did not allow matter to condense out from the highly concentrated energy of TBB. There is no agreement whether matter existed at all during the BB inflation era. The proposed equations seem to imply that there was not. There is still argument as to when the proposed inflation period ended. Some believe that it never ended and continues today as dark energy. Others believe in Einstein's cosmological constant concerning an explanation for the hypothetical dark energy. Concerning gravity, some theorists might say that gravity does not exist at all in the absence of matter. Most believe that gravity existed from the beginning.

.

Anyway the point I was really getting at is that space without matter seems to be an accepted part of another theory.

There are cosmological models like the De Sitter model where an entire universe of space exists without any matter. But since this would not be our universe, theorists would probably find it difficult to use such a matter-free universe model except within maybe a multiverse model. Some believe, however, that the Zero Point Field is an infinite continuum and that it preceded a BB beginning and was the source/ cause of that beginning. This is an infinite universe, infinite space, but finite mass model. Others like Hawking have proposed multiverses/ other worlds, proposing our BB universe is only one universe of many or infinite quantities. This is another "infinity" model of reality.

.

Space without field is somewhat different.

Calling some hypothetical volume(s) "space" when there would be no matter or field within or surrounding it, makes no sense at all to me. This is my problem with a definition of space which includes the idea of a continuum if matter and field are finite in quantity as in the standard version of the BB model. Based upon a flat universe model and Einstein's concept of space (also mine), there is no such thing as space beyond the boundaries of matter and field, since accordingly matter and field must be used to define space. Einstein also seemed to believe that the concept of totally vacant space was inconsistent with his cosmological equations based upon GR, when he said "...space does not exist in the absence of field."

Trajk Logik,

......... What I don't understand is why one would conclude that the universe has always been expanding. Could it not be possible that the universe is eternal and that the expansion is something that started happening recently? Could it be possible that some outside force may be pulling on the universe from the outside? .

Of course there are possibilities but the BB model does not allow such possibilities. Only in a Steady State Universe could these possibilities be real. Few presently believe in the possibility of a Steady State universe, even one that is expanding.

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Another idea is that maybe the big bang did happen but the universe hasn't been expanding at a constant rate.....

That the universe is not expanding at a constant rate is the basis for the dark energy hypothesis, which has now been included in the BB model.

Although I see logic in your proposal, there may be a problem. Theory concerning Type 1a supernova involves two possibilities. One is that a white dwarf star sucks the atmosphere from a surrounding red giant star in a close orbiting binary star system causing the white dwarf star to explode. The other possibility discussed is the collision of two white dwarf stars in a close binary system. In both cases a white dwarf star is thought to be exploding. If the supernova explosion does not meet the required profile concerning spectrum, brightness, after glow profile involving rate and time of dimming, etc. then it would not be considered a type 1a profile and classified differently. Such white dwarf stars are thought to be between .5 and 1 solar masses. These explosions are very uniform. That is why they are considered to be standard candles. Although there are some recognized variations within this select group, if there is very much difference in the profile of radiation then it will be otherwise classified so that your ideas might only explain minor variations. If more differences are recognized in time, then more supernova might be otherwise classified to the benefit of the data base. It will be a good thing when the causes of differences are better understood so that those that do not meet a more stringent profile, will not be considered type 1a standard candles and data averaging (redshift bin data) will become more accurate.