My understanding is that the cosmological constant, though poorly understood, is assumed to be uniform in space. Does this uniformity extend to small scales or is it only uniform at very large scales.
I don't know at quantum scales ... but at macroscopic scales, the expansion rate of the universe is not uniform in space. It has been described as analogous to the baking of a cake with raisins, in which the raisins correspond to galaxies or clusters of galaxies. Space between the galaxies/clusters is expanding but the galaxies/clusters themselves are not. This is a property of solutions to the Einstein equation if dark matter + normal matter is clumped in galaxies/clusters. The repulsive force of dark energy is dominated by attraction due to normal matter. So the Andromeda Galaxy and our Milky Way Galaxy are moving toward each other with gravitational attraction, and macroscopic motions within our Galaxy and solar system are dominated by gravity from dark matter and normal matter.
The universe expansion rate is not constant because of gravitation!
I am the first who realized that the gravitons with the speed of light will not escape a black hole. This means if the (gravitation) gravitons have the speed of light like Einstein field equations confirm, the black holes will not attract anything.
General relativity, LQG, String theory, Quantum gravity theories are wrong theories because are limited to the speed of light and do not explain Gravitation.
“I am the first who Understood and Explained Gravitation with high speed gravitons v = 1.001762 × 10^17 m/s, with Negative Impulse, Negative Mass and Negative Energy” Adrian Ferent
The cosmological constant, if that is the "real thing" behind dark energy, must really be constant in space and time. Other models for dark energy in principle allows for variation.
But there are additional contributions to the expansion dynamics. F.i., it is generally expected that the space between stars in a galaxy does not expand; galaxies in the expanding universe are like raisins in an expanding dough.
Ruffolo. Sorry for essentially repeating your answer; it was not visible to me when I wrote it.
A bug seems to have appeared on RG Q&A lately; answers do not always appear immediately.
Thanks for nice answers. I'd like to ask a follow-up question. Is it accepted that the cosmological constant has always been the same?
Esa> Is it accepted that the cosmological constant has always been the same?
I think not; the theory of inflation requires the inflation to end after some time. This can be described by an inflaton field which rolls slowly to zero. I.e., by an effective cosmological constants which decays with time.
Thanks for the comments. Please indulge me for a few more thoughts. I apologize if these issue are well discussed elsewhere and I have not been able to find them. If the cosmological constant originates in the vacuum or zero energy as postulated, that should be the same within a galaxy and outside of it with the possible exception of Pauli exclusion issues in regions where dense matter already exists (i.e, stars and planets). Since the volume fraction of traditional matter in a galaxy is exceptionally small, it seems the cosmological constant should be only trivially smaller inside galaxies compared to outside them. The reason the galaxies and galaxy clusters do not expand is possibly because gravitation is sufficiently high to overcome the expansion, not because the cosmological constant is for some reason zero in the galaxy and non-zero outside of it.
The relative contribution of dark energy (cosmological constant) and non-relativistic matter (of known and unknown type) is on average roughly 70% to 30%. However, in a (our?) galaxy the average density of non-relativistic matter is estimated to be about 200 times larger than average, while the dark energy contribution is expected to be unchanged. Hence, non-relativistic matter is the absolutely dominating contribution to gravity in galaxies, it is simply not an exceptionally small part.
I understand that non-relativistic matter dominates gravity. However, it occupies a very small volume fraction of the galaxy. It would seem that whatever mechanisms are driving expansion/cosmological constant in the universe as a whole would also be operative inside the galaxy except possibly in regions occupied by non-relativistic matter.
The core of the question, I suppose, is what is driving expansion. The most tenable answer of which I am aware is the zero energy of a vacuum. If this is the case, it would seem expansion would be operative nearly everywhere, with the possible exception of the vanishingly small fraction of a galaxy occupied by non-relativistic matter.
Another possibility is there has been no ongoing expansion, and we are in the steady state of a static universe,
so a constant expansion rate of zero in every direction :)
per one cosmological redshift hypothesis:
It has been static since the end of the initial inflation/expansion, very early in the history of the universe,
Roger> It has been static since the end of the initial inflation/expansion, very early in the history of the universe
Then, how would you explain that it is not an extremely hot fireball? Already Olbers understood that was a problem 200 years ago.
My understanding is that relatively recent (circa 2000) data establish convincingly that the universe is expanding in the sense of new space being created and that this expansion is accelerating.
Larry> with the possible exception of the vanishingly small fraction of a galaxy occupied by non-relativistic matter
This is a wrong way to reason; you must consider averages of sufficiently large scales, for which I gave relevant numbers. Even solid iron consists of a vanishingly small fraction occupied by matter.
Hi Kare,
one way is
it started at a singularity, than expanded a bit before inflating.
perhaps an inflation from 1 LY radius to 13 B LY radius.
the expansion would have dissipated the heat.
also we do not know how hot it was, as there are variables and assumptions involved in how the expansion and inflation occurred.
Roger. You have to explain nucleosynthesis. You have to explain gravitationally driven development of structure (f.i. galaxy formation), not too fast -- not too slow.
And you will of course have to explain the development of redshift.
Hi Larry,
i know that is the current conventional view, and much of modern cosmology is built on the assumption cosmological redshift is due to an expanding universe, but there are other (at least one - The Pearlman SPIRAL as explained in 'Distant Starlight and the Age, Formation and Structure of the Universe') models that fit the same factual observations/measurements of cosmological redshift that are consistent with a static universe and not an expanding one, that have not been fully considered yet by the vast majority of scientists.
Hi Kare,
While there may be other models of a static universe, The Pearlman SPIRAL holds the proto stars preceded the vast majority of the inflation expansion.
how they could have formed, how dense they were prior to that expansion/inflation, how that can be reconciled with all the factual observations, is something i hope to get help from knowledgeable scientists with. Please see the applicable questions on my researchgate profile.
Distant Starlight and the Age, Formation and Structure of the Universe explains why the cosmological redshift (CR) has a much greater probability of being explained by the Pearlman SPIRAL hypothesis and not due to the current assumption that CR is due to an expanding universe.
best,
r
Roger> not been fully considered yet
... an 5,776 year old universe, and more ...
Looks like a show-stopper to me.
Nobel Prize for Gravitation!
Who is the smartest to explain Gravitation?
900 Nobel Laureates and they were not able to explain Gravitation, the most important force in nature.
In my view the graviton must have a speed higher then the speed of light; the gravitons with the speed of light will not escape a black hole.
General relativity, LQG, String theory, Quantum gravity theories are wrong theories because are limited to the speed of light and do not explain Gravity.
“I am the first who Understood and Explained Gravitation with high speed gravitons v = 1.001762 × 10^17 m/s, with Negative Impulse, Negative Mass and Negative Energy” Adrian Ferent
https://www.researchgate.net/publication/287331589_Ferent_Gravitation_theory
It is interesting. But 'velocity more than that of light' and concept of photon and Energy and wave equation E=hf have to be considered on completely fundamental basis (from definitions itself). I will consider it for discussion as per my time permits.
Thank you
The simple answer is no.
Hubble tells us that it depends on the distance form us. So the maximum recession velocity is c in our observable UnIverse.
It is most probably c^2 in our entire UNIverse
Book Everything is Physics Book 2 The quantum continuum dark matt...
Hi Kare,
if the Pearlman SPIRAL is valid, by eliminating the wasted brainpower, time and other resources, barking up the wrong tree as we have done for the past 185 years with deep time doctrine assumptions. So science can focus on the YeC actuality and make scientific progress at a much greater rate than under the current prevalent deep time bias.
Newton and Einstein were two legendary alchemists.
They studied all their life what they did not understand: Gravitation!
When they were young they stolen from others theories, but after people started to watch them and they were not able to steal anything, they did not discover anything.
General relativity, LQG, String theory, Quantum gravity theories are wrong theories because are limited to the speed of light and do not explain Gravitation.
“I am the first who Understood and Explained Gravitation with high speed gravitons v = 1.001762 × 10^17 m/s, with Negative Impulse, Negative Mass and Negative Energy” Adrian Ferent
https://www.researchgate.net/publication/287331589_Ferent_Gravitation_theory
Constant rate of expansion depends on
1. The force like Big bang. If it is due to Big bang the rate may not be constant.
2. If it is due to forces like ‘contraction’ and ‘expansion’ due to ‘space time’ causing gravity, it is theoretical and the cosmological constant will be constant and rate of expansion is constant.
3. What is space time? How it originates? If one space time represents gravity which is one of four natural forces then, Can we apply the same space time to other natural forces which may affect gravity? Thus expansion may be affected by it. These fundamental concepts require a final and appropriate theory of ‘Grand unification’ explaining the universe.
4. Not only this- Some of the researches on ‘Consciousness’ says that the expansion is due to a fact that ‘life and Universe obeys Constant of light (of Special Theory of Relativity)’. Thus expansion will have constant rate caused by consciousness. But further research on consciousness supporting that time coordinate is affected by consciousness also. So consciousness (differs with observer) will not support Constant rate of expansion.
Anyhow experimental observations only decide the ‘constant rate of expansion’. At the same time theoretical calculation of ‘Grand Unification’ ,’consciousness’ and ‘neurosciences’ and experiments in that direction will move the science a little further, if scientist initiate appropriate research. Let us hope the best.
Andrew> the maximum recession velocity is c
No. That is a misunderstanding.
Adrian Ferent> I have gone through the paper entitled ' Ferent Gravitation theory' Further to my comment on your paper I would like to say the following
Simply your concept can explained as-
1. The ratio of electric charge force and gravity force is considered as ‘s’
2. The same fraction ‘s’ is reducing plank constant ‘h’. So energy of graviton will be less. In this why we are reducing ‘h’. We can reduce ‘f’ . If we reduce ‘f’. It is a ‘low frequency photon’ only.
3. If you keep ‘a’ instead of ‘h’ for gravitons the ‘f’ will be constant. And if we keep ‘c’ as constant’ in ‘c=f x wavelength’ the wave length will be changed. Then change of ‘h’ to ‘a’can be considered.
4. Means we are keeping ‘c’ as constant to say E= fa. We cannot say E=af and ‘velocity more than that of light’ at the same time.
You are so strong that you are blaming good intellectuals like ‘Newton’ and ‘Einstein’ so rudely which is not tolerable by scientific community.
Anyone can put forth new ideas without insulting others. I will encourage such attitude.
Any How, I had provided some reasons with my little knowledge and logic and cannot go ahead with your ideas. Thank you.
Adrian Ferent>If we won't reduce 'f' we have to reduce t 'h' to 'a'. Both the cases are same. For radiation 'h' is constant we can not reduce it. So the same can be observed as reduction in 'f'.
We are reducing 'h' means we are changing all the laws of science including time(for example :our 1 sec may be its 2 sec and length also may be different every thing will be different) in maths if we say 1 as 2 complete maths will be changed. But we have certain experimental results and definitions for science. Based on them only we can define new. If any separate universe exists beyond our universe we can define this 'a' for its energy.(Energy also will be less in that universe). It is beyond my imagination. Sorry!
Please talk about my theory!
The photon energy is my equation: E=af + hf
Adrian> Please talk about my theory!
Fuzzy. With a lot of cut-and-paste of misunderstood ideas and concepts.
To Larry (broadly),
The universe's expansion rate is not constant in space. The expansion rate divided by the distance - the Hubble parameter - is constant in space at cosmological scales. It is not constant in time : see RG discussion on "What is the expansion rate of the universe ?". The cosmological constant is not the expansion rate. It has to be discussed in the frame of Einstein's General Relativity equations, see article by Tamara Davis in Scholarpedia. It is constant in space and time. Concerning universe's acceleration (discussions around Riess/Perlmutter's teams observations, dark energy, cosmological constant, ....), see enclosed slides. On what occurs with the cosmological constant at quantum scales : this is one of the numerous questions to be answered by a "future" theory reconciling General Relativity and Quantum Mechanics (there are a lot of efforts at present time to develop such a theory : Loop Quantum Gravity, String theories, etc).
Regards
https://www.researchgate.net/post/What_is_the_Expansion_Rate_of_the_Universe
http://www.scholarpedia.org/article/Cosmological_constant
Dear Larry,
in some other threads I emphasized my proof that in my quantum gravity theory one can justify expansion of the universe as a legacy of its Planck epoch. Then one can understand that such an expansion cannot be constant following a quantum energy conservation law !
Interested readers can look the following my paper: http://arxiv.org/abs/1206.4856.
This information should completely answer to your question.
My best regards,
Agostino
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