Thread: The shape of the universe

I am trying to unterstand the basic ideas of cosmology and big bang theory. First of all: the shape of the universe, I found two different pictures:
1) Big Bang - Wikipedia, the free encyclopedia and 2) Universe - Wikipedia, the free encyclopedia .

In 1 universe is a flat surface, the base of a pyramid, in 2 stars are shown within the surface of a funnel-shaped cylinder, which is not flat.

could you tell me which is right, or do they refer to different theories? Could you tell me also if:

3) all mass/matter existing now was in the singularity
4) the particles are travelling at the speed of light
5) all particles/mass were expelled at once or some matter remains in the singularity
6) space exists also inside the whole pyramid/funnel
thank you.

In 1) the universe is a flat surface, the base of a pyramid, in 2) stars are shown within the surface of a funnel-shaped cylinder, which is not flat.

could you tell me which is right, or do they refer to different theories?


These are just illustrative diagrams. They should not be taken literally. You need to “read between the lines” in the explanatory text too.

The shortest answer is that the universe is a minimum four dimensional object in space and time. Its shape is assumed to be spherical, but this is mainly because we can perceive objects and phenomena only by observing in all directions. Our observations are limited by the speed of light, c. So everything that we can perceive must occur within a radius defined by c. What that radius is, exactly, is what the fuss is all about. But, things have settled downto the tentative conclusion that r = 14.72 billion light years with an age of 14.72 billion years. This is just a very rough approximation, though. There are other considerations (like the fact that we see light that we can only say has been traveling for but14.72 billion years) that make the actual radius rather a lot larger. But, the universe is still thought to be essentially spherical. But, it follows Euclidean geometry, not some sort of curved geometry that seems to violate perception. Euclidean geometry means “flat”. That is, the angles of a triangle all add up to 180 degrees. The cosmic background radiation (CMB) shows this in a rather straightforward manner.

But, there are strong arguments for the view that its size is very much lager than we can see or that it is infinite or that there are many other universes and “times” – the multiverse or metaverse and metatimes. So, it may be hard to assign an overall shape here.

By some measures, the universe is perceived to be as follows:

In modern physical cosmology, the cosmological principle is the working assumption that observers on Earth do not occupy an unusual or privileged location within the universe as a whole, judged as observers of the physical phenomena produced by uniform and universal laws of physics. As astronomer William Keel explains:

The cosmological principle is usually stated formally as 'Viewed on a sufficiently large scale, the properties of the Universe are the same for all observers.' This amounts to the strongly philosophical statement that the part of the Universe which we can see is a fair sample, and that the same physical laws apply throughout. In essence, this in a sense says that the Universe is knowable and is playing fair with scientists.
The cosmological principle contains three implicit qualifications and two testable consequences. The first implicit qualification is that "observers" means any observer at any location in the universe, not simply any human observer at any location on Earth: as Andrew Liddle puts it, "the cosmological principle [means that] the universe looks the same whoever and wherever you are."

The second implicit qualification is that "looks the same" does not mean physical structures necessarily, but the effects of physical laws in observable phenomena. Thus, wavelength ratios observed for different ionic species in the absorption spectra of quasi stellar objects (QSO or quasars) place a limit on any variation in the fine-structure constant to less than 1 part in 1 million out to a distance in space (and time) of z = 3 (about 6500 megaparsecs or 11.5 billion years); as the fine-structure constant is determined by the relation between the speed of light (c), Planck's constant (h) and the electron charge (e), these physical constants are constrained as well.

The third qualification, related to the second, is that variation in physical structures can be overlooked, provided this does not imperil the uniformity of conclusions drawn from observation: the sun is different from the Earth, our galaxy is different from a black hole, some galaxies advance toward rather than recede from us, and the universe has a "foamy" texture of galaxy clusters and voids, but none of these different structures appears to violate the basic laws of physics.

Could you tell me also if:

3) all mass/matter existing now was in the singularity

Yes.

4) the particles are travelling at the speed of light

All matter and energy was indistinguishable at some point as we move deeper into the past. So it was all most similar to light. At that time, however, it is really hard to say how fast it was traveling. Its temperature was possibly several exponential DECADES of degrees Kelvin, however. I think this is meaningless though, given the high field strength and small distances involved. Time slows in an intense gravity field and nothing was more intense than gravity was way back then. Distance was distorted greatly too, by the intense gravitational field.

5) all particles/mass were expelled at once or some matter remains in the singularity

This is a good question.

But, the quantum interpretation of Alan Guth’s Inflation Theory implies that all matter in the initial “Inflaton” particle is now gone – that is, it is all around us, everywhere, right now.


6) space exists also inside the whole pyramid/funnel

Remember, it’s just a diagram. But the funnel shape may better be to represent a spherical volume and the “funnel” may represent just what we can or could have perceived of the universe, based on the speed of light constraint.

Originally Posted by Gary Anthony Kent

1) The shortest answer is that the universe is a minimum four dimensional object in space and time.
2) Its shape is assumed to be spherical,....universe is still thought to be essentially spherical. .

Thank you Gary, for your painstaking reply. I know physics, that's why I am trying to understand BB, I need only some basic data only about it.
could you answer my questions one by one?

1) every thing in the world is in space and time, right?, space is defined as a property of a body, right? mass in the singularity loses this property?
2) see here Shape of the Universe - Wikipedia, the free encyclopedia, you mean Ω > 1?

Originally Posted by Gary Anthony Kent

3) all mass/matter existing now was in the singularity Yes.
4) the particles are travelling at the speed of light. , hard to say how fast it was traveling.
4b). Time slows in an intense gravity field
5) all particles/mass were expelled all matter in the initial “Inflaton” particle is now gone –.
6) space exists also inside the whole pyramid/funnel funnel shape may better be to represent a spherical volume .

I should have waited a few minutes! Gary
I must now wait for your answer to 2) before I can comment the other points

But start considering this: they say that time and space began with the BB, can this be true?
3), 4b) a huge mass can be compressed only to a certain point, but it must exist in space, else id doen't exist, is that right?. time slows or stops, but if it slows or stops all physics law cease to exist?, including gravitation, radiation etc...
5) if all mass was expelled at once, all particles would be more or less at the same distance, or they travel at different speeds?
---
7) what energy caused the BB?

Originally Posted by Gary Anthony Kent

But, the quantum interpretation of Alan Guth’s Inflation Theory implies that all matter in the initial “Inflaton” particle is now gone – that is, it is all around us, everywhere, right now.
.

I tried wiki but I couldn't find mention or details of this implication, could you, or someone give me a link to get more info?

Thank youGary, for your painstaking reply. I know physics, that's why I am trying to understand BB, I need only some basic data only about it.

Could you answer my questions one by one?

1) every thing in the world is in space and time, right?,


By GR everything IS space & time – spacetime. There is no distinction. It is the meaning of E = mc^2


Space is defined as a property of a body, right?


Objects define their spaces, yes. And vice versa.


Mass in the singularity loses this property?


NOT SO FAST. Stephen Hawking has retracted his paradoxical view that matter loses its total identity when it falls into a black hole. He now says matter retains its signature in the form of an entropy increase that shows up as a sort of “image” on the surface of the event horizon. This entropy can be read back to us as “Hawking radiation”. He is backed up by many others’ calculations. He has a cute little formula for the total entropy of a black hole too. It is like Shroedinger’s equation or Einstein’s formula.

2) See here Shape of the Universe - Wikipedia, the free encyclopedia, you mean Ω > 1?


Ω = 1 means only that the universe must be considered to be flat in a Euclidean sense. If Ω > 1, the universe is curved onto itself and will collapse, usually very quickly. If Ω < 1 then the universe is supposed to be “open”, topologically curved like a saddle – having curves or "sheets" in opposite senses.


3) All mass/matter existing now was in the singularity Yes. Yes. Yes.

4) The particles are travelling at the speed of light. , hard to say how fast it was traveling.

4b) Since Time slows in an intense gravity field


5) All particles/mass were expelled... meaning all matter in the initial “Inflaton” particle is now gone – but this is only an assumption

6) Space exists also inside the whole pyramid/funnel The funnel shape may better be said to subsist inside a spherical volume with the funnel shape just a segment or slice that we can perceive.

Note that the funnel shape implies we can see into the past, but not the future. Some say this is in doubt too.


I should have waited a few minutes! Gary, I must now wait for your answer to 2) before I can comment on the other points

But start considering this: they say that time and space began with the BB, can this be true?


Not really. As soon as one starts to talk about the objective reality of spacetime, one begins to assume another sort of time and space or a meta-time and meta-space or even meta-spacetime. We get into different whole universe timelines and we start to think in terms of the “Many Worlds” interpretation of Quantum Mechanics and “parallel universes”. But, even Alan Guth concedes that his account of “Inflation” did not begin at the very beginning. He acknowledges that this would be impossible anyway because the laws of physics could not be certain at t = 0, exactly. Little is said about what came “before” t = 0. But, the ultimate black hole must have pre-existed as a singularity having a singular, hyperbolic gravitational field. This is all that can be said about the pre-big bang Inflaton Particle other than it existed and that it existed in an extremely high energy state.

3) & 4b) a huge mass can be compressed only to a certain point, but it must exist in space, else it doesn't exist, is that right? Time slows or stops, but if it slows or stops all physics laws cease to exist? Including gravitation, radiation etc...

Things just cease. They do not cease to exist. But, is not this the same thing? Unless you switch to another universe meta-timeline. Then the whole universe may be considered just another object. Are we getting mystical enough yet?

5) If all mass was expelled at once, all particles would be more or less at the same distance, or they travel at different speeds?

Interesting idea.

Could inflation have occurred in spurts? Could the universe be layered in time? If the layers begin to overlap in time as some of the particles catch up to the leaders, might this have consequences? The Law of Parsimony says NO. It is gratuitous complexity that is unnecessary to explain things.


7) What energy caused the BB?


Alan Guth theorizes that the enormous energy implied by the BB came from the statistical probabilistic conception of the “Inflaton” particle coming to be in a very very high energy state. Particles in such states are always unstable. So, eventually, it decayed. Such decay IS the BB.

Originally Posted by Gary Anthony Kent:

But, the quantum interpretation of Alan Guth’s Inflation Theory implies that all matter in the initial “Inflaton” particle is now gone – that is, it is all around us, everywhere, right now.

This too is an assumption. – G.A.K.

I tried wiki but I couldn't find mention or details of this implication, could you, or someone give me a link to get more info?


Try Guth’s book “Inflation”, Brian Greene’s book “The Fabric of the Cosmos” and their bibliographies or the many popular magazine articles that you can easily find at any library or even online. Keep an eye on the current magazine shelves in stores. Or else look into “radioactive decay”. I doubt that you will ever find an explicit statement of this, one that you could cite.

questions number = black; answer-by-gary number (colour added : blue) blue text = I agree,

Originally Posted by Gary Anthony Kent

1) the particles are travelling at the speed of light? [10) All matter and energy was indistinguishable] , 1) it is really hard to say how fast it was traveling..
2) all particles/mass were expelled at once or some matter remains in the singularity? 2) This is a good question...2) all matter in the initial “Inflaton” particle is now gone – that is, it is all around us, everywhere, right now.
3) space exists also inside the whole pyramid/funnel? 3) the funnel shape may better be to represent a spherical volume and the “funnel” may represent just what we can or could have perceived of the universe, based on the speed of light constraint.

Originally Posted by Gary Anthony Kent

4) By GR everything IS space & time – spacetime. [9) There is no distinction. 10) It is the meaning of E = mc^2]
4)Mass in the singularity loses this property? NOT SO FAST. Stephen Hawking 4) has retracted his paradoxical view
4b) SinceTime slows in an intense gravity field
2) All mass/matter existing now was in the singularity 2) Yes. Yes. Yes.
1) The particles are travelling at the speed of light. ,1) hard to say how fast it was traveling.
2) All particles/mass were expelled... meaning 2) all matter in the initial “Inflaton” particle is now gone – but this is only an assumption
6) Space exists also inside the whole pyramid/funnel 3) The funnel shape may better be said to subsist inside a spherical volume
4)But start considering this: they say that time and space began with the BB, can this be true? 4) Nott really.
4) a huge mass can be compressed only to a certain point, but it must exist in space, else it doesn't exist, is that right?
5) Time slows or stops, but if it slows or stops all physics laws cease to exist? Including gravitation, radiation etc... 5)Things just cease. They do not cease to exist. But, is not this the same thing? Unless you switch to another universe meta-timeline. Then the whole universe may be considered just another object. Are we getting mystical enough yet?
6) If all mass was expelled at once, all particles =>6) would be more or less at the same distance 6) interesting idea.Could inflation have occurred in spurts? Could the universe be layered in time? If the layers begin to overlap in time as some of the particles catch up to the leaders, might this have consequences? 10) The Law of Parsimony says NO. It is gratuitous complexity that is unnecessary to explain things.
7) What energy caused the BB? 7) Alan Guth theorizes that the enormous 7) energy implied by the BB came from the statistical probabilistic conception of the “Inflaton” particle coming to be in a very very high energy state. Particles in such states are always unstable. So, eventually, it decayed. Such decay IS the BB.

Thanks, Gary , for your painstaking attention to details ! , now, see if my (not assumptions) deductions are sound

1) my question was rethorical. Speed of explosion must have been C , because, now, (time elapsed) T is 14B years and (radius of observable universe) R is 46B light years = 14 x C x R ( allowing for some bad arithmetics); speed of expanding univere is still C (with a marginal error -+ e) right?

2) all matter must have been expelled because the remainder-primeval-BH would exert a G-force and perturb the equilibrium of the universe,( independently of what Guth thinks), right?

3) why use a funnel to represent a sphere? the funnel shows expansion in one direction and that violates 3rd law of motion.(btw: can you make a drawing, or an animation, that would be great!)

4), I agree with you, I was checking the validity of what I read, (you can read all sort of things on this issue). I do not agree on the ontological-status motivations. I would like to stick to mainstream, to the currently valid laws of mechanics, I do not want to be misunderstood, I do not want to talk metaphysics , just sound physics.
So my justification is a) that space is a property of mass (and energy: photons) and as long as 10^ 54 kg exist, (even if constrained, compressed in a BH), they must take up some space, and b) if you abrogate time all laws of physics depending on time grind to a halt. Is this correct?

5) I really do not comprehend that

6) This is a very sensitive issue (alongside with next: 7): GR (and why Occam's-razor?) say(s) happened at once. You say that (6) is interesting. If 6 then 6 => 6 = matter, particles should be expanding like in a firework, like a wave

7) this is the core of the issue of BB: cosmology/cosmogony. I am glad you (like many astrophycists) are keen on phylosophy, because that IS metaphysics I imagine you are familiar with Heraclitus, the Hindu myth of the expanding egg, the Chinese myth of Pangu, etc, because with 7 we enter the realm of cosmogony and this,
strictly speaking is not within the jurisdiction of science, since it is a one-off event.
We can continue to discuss it here, or I will make a new thread on BB. As you wish!
I hope you agree that 7 is meaningless, just a pitiful exercise in mirror-climbing.
Flaws are many: to shoot 10^ 54/60 Kg of matter at (nearly) C requires more energy than existed in the BH and in the universe, if it existed elsewhere how would it "come about" be "conjured up", how would it penetrate right to the very center of the singularity without been annihilated, etc
8) Why can't be universe be a sphere? whay can't be Ω > 1?, why should universe collapse?

[9) I am glad you say that, let's keep GR out of our discussion, as long as we can,10) I disagree, but will not discuss this (unless you want to know my opinions), as I think this, too, is foreign to discussion]

Thanks a lot again, Gary, please comment the 8 points,
you are really an ideal interlocutor!

(btw, moreover, with big letters I do not need my glasses, I'm joking try to scale it down)[/SIZE]

If I may...

Originally Posted by ray

1) my question was rethorical. Speed of explosion must have been C , because, now, (time elapsed) T is 14B years and (radius of observable universe) R is 46B light years = 14 x C x R ( allowing for some bad arithmetics); speed of expanding univere is still C (with a marginal error -+ e) right?

The speed of the expansion has been changing throughout the history of the universe. It is common to use the distance to the particle horizon as an example here, as that is the basis for the size of the observable universe.

The particle horizon is currently 46 billion light-years away, as you said. That is the distance, "today", to the place where the Cosmic Microwave Background we currently detect was released, if that place has receded with the expansion of the universe, and remembering that the CMB comes in from all directions, that distance is the radius of the conceptual sphere that represents our observable universe. If that horizon had been receding at the speed of light for the history of the universe, as you suggested, it would only be 13.7 billion light-years away, as the universe is only 13.7 billion years old.

In an expanding space, where distances increase with the expansion, there is a point beyond which distance increases faster than c, known as the Hubble distance. The particle horizon is more than three times more distant, meaning that the edge of our observable universe would have had to recede at more than three times the speed of light, on average, to reach 46 billion light-years in only 13.7 billion years.

In order to discuss these issues in a convenient way, I should point out that there are a few different definitions of distance in cosmology and they don't all mean the same thing. Here is quick and dirty guide for you (pardon the link, but it is an excellent introduction, even if the figures are slightly out of date):

The Distance Scale of the Universe

Or, if you are feeling adventurous, you could have a look at this post I made a while back.

Obviously ray,you have not belief in in current accepted theories.Sorry to be so blunt,but i feel you haven't even studied these theories,as you clearly demonstrate.my only suggestion to you,is that you do study them.They involve not just ideas,but proof of the idea being correct..of course one could be philosophical,but that is akin to shooting yourself in the foot.(best anology i could be bothered with)
Please study accepted theory,before feebly attempting to deconstruct it....no disrespect intended

Originally Posted by SpeedFreek

1) If I may...
2)The speed of the expansion has been changing throughout the history of the universe. .

Hi speed,
1) glad to see you here, you must have read my mind, because I was going to refer you to this thread , so that you might see how a serious discussion between scientists proceeds.
you can see here how a real scientist (G.A.K, and in "the core of a supernova" Dishmaster), (that is an intelligent person) reacts to a new, provoking, unexpected challenging argument:
" wonderful question" , "interesting question"... etc. If the argument is valid he agrees, if he thinks it is false he produces new arguments.
Nobody here ever asked or questioned my qualifications, they simply addressed the arguments.

I am not going to answer your last post in "standard model", but as I am fair, I wanted to tell you, and I am doing it here, that "you are right" when you say you were not the first to attack me, but my "you" was not referring personally to speed, but to the forum. I was coming there from I civil discussion here, I was shocked and I wanted to show you that if you attack me, I'll react according to the 3^rd law.
I will ignore branewave, as I will ignore here all posts whose only argument is ad hominem

2) Now, coming to your concrete "argument", speed (I like you, you are a nice bloke, I am sincerely sorry I was harsh with you)
you are replicating your methological fatal mistake: you are justifying a hypothesis quoting the hypothesis itself, you are taking for granted a mere hypothesis that has not peen proven and cannot be proven bacause it regards a one-off event.
That is science, you can question that, but if you do you are destryoing it. Do you understand that? I gave you links to mainstream , you give me links to a hypothesis that is not correct, fair, acceptable.

The point is not how well I now the "theory". I know it ( and proven science) enough to criticize it.
Speed do you realize I am questioning the logical, scientific validity of your links? Do you know that your links haven't proven ( and can never prove) a thing? it is only guesswork, a question of logic and you cannot violate proven science by a guessing game.

"The speed has been changing, grew exponentially", during inflation volume grew 10⁴⁶ etc, are all an exercise in fantasy. These guys are making fun of you, they say something risible, you repeat it, and then they retract it, and you keep repeating it.

so , if you accept a crazy idea without an adequate explanation , you take on yourselfthe burden of proof, (which is mission impossible), or the burden of logical argumentation, which is extremely difficult and above your possibilities.
so, if you repeat that crazy idea here, you (this time you speedfreek) are obliged , (if even a fool like me questions that), not to prove, because nobody can, but to invent a plausible, coherent, logical, scientific explanation for this:

a) is change of speed at all possible in principle? if you prove that then you must answer: what is the cause of that change? where does the necessary energy come from? how can it be greater that C? why does after that speed decreases ? and so on , and so forth.
I hope this time it is clear, because I am not going to repeat it again.

As far as expantion of space is concerned, you are behaving like the "last Japanese", because theorists have long acknowledged their mistake (I don't know if I am allowed here to quote another forum where even Dr Rocket is a member) but if you vist it, you'll see that the "award : best cosmologist of the year" has changed his tune and acknowledges that "space is not a substance, cannot expand"

So, I have apologized for my reaction, I hope you acknowledge that your methodological, epistemological aproach to these issues is wrong.

Originally Posted by ray

Hi speed,
1) glad to see you here, you must have read my mind, because I was going to refer you to this thread , so that you might see how a serious discussion between scientists proceeds.

Hmmm, snarky from the off, eh? If you want to search through my posts either here, or at BAUT, you will see that I know how to conduct a serious discussion. You are judging me based purely on our only exchange, and it was your attitude that dictated my responses. See the post in the link below, for instance:
The Oldest Galaxy

Originally Posted by ray

Nobody here ever asked or questioned my qualifications, they simply addressed the arguments.

And I never questioned your qualifications either. It was you who claimed to "know physics" whilst posting assertions without any basis in cosmology (to be fair, you are citing science that has a different domain of applicability - space has a specific meaning in GR, and inherits properties based on its contents) so I pointed this out to you.

Originally Posted by ray

I was coming there from I civil discussion here, I was shocked and I wanted to show you that if you attack me, I'll react according to the 3^rd law.

If you wanted civil discussion, why did your replies to my quite standard answers in "the standard model" thread use words like "spooks", "undefined terms" (which you actually misread - the hubble flow is well defined), "risible properties" and "magic"? These emotive responses are not terms usually used in a civil, scientific discussion.

Originally Posted by ray

2) Now, coming to your concrete "argument", speed (I like you, you are a nice bloke, I am sincerely sorry I was harsh with you)
you are replicating your methological fatal mistake: you are justifying a hypothesis quoting the hypothesis itself, you are taking for granted a mere hypothesis that has not peen proven and cannot be proven bacause it regards a one-off event.
That is science, you can question that, but if you do you are destryoing it. Do you understand that? I gave you links to mainstream , you give me links to a hypothesis that is not correct, fair, acceptable.

Your responses seemed to show that you had misunderstood the theory, so I thought you needed more information in order to understand the theory you are arguing against. It is a theory, as it makes testable predictions. All my links are always to the mainstream scientific view, as far as I am aware.

Originally Posted by ray

The point is not how well I now the "theory". I know it ( and proven science) enough to criticize it.

Based on some of your statements, I don't agree. For instance, there is no such thing as "proven" science. Nobody who understands physics, or the scientific method, would ever use the term "proven science".

Originally Posted by ray

Speed

Originally Posted by ray

do you realize I am questioning the logical, scientific validity of your links?

In which case you are questioning the logical scientific validity of mainstream science. A lot of people who don't really understand the theory do this.

For instance, is it logical for two identical twins to be the same age at a certain time, but to be different ages later on? A lot of people baulk at this notion, and millions of words have been sent across the internet claiming it cannot be true.

Originally Posted by ray

Do you know that your links haven't proven ( and can never prove) a thing? it is only guesswork, a question of logic and you cannot violate proven science by a guessing game.

Science never proves anything - it waits for an experiment that disproves the model. All scientists understand this, so there is no such thing as "proven" science. Science is either disproved, or yet to be disproved - we are always challenging our theories and looking for better theories.

Originally Posted by ray

"The speed has been changing, grew exponentially", during inflation volume grew 10⁴⁶ etc, are all an exercise in fantasy. These guys are making fun of you, they say something risible, you repeat it, and then they retract it, and you keep repeating it.

so , if you accept a crazy idea without an adequate explanation , you take on yourself the burden of proof, (which is mission impossible), or the burden of logical argumentation, which is extremely difficult and above your possibilities.
so, if you repeat that crazy idea here, you (this time you speedfreek) are obliged , (if even a fool like me questions that), not to prove, because nobody can, but to invent a plausible, coherent, logical, scientific explanation for this:

There you go again - "fantasy", "risible", "crazy". These are not rebuttals, nor are they reasons why the theory is wrong. The mathematics all support the theory, and so do observations, so it is up to you to show why that theory is fantasy, risible or crazy, rather than simply asserting it - an argument from incredulity.

Originally Posted by ray

a) is change of speed at all possible in principle? if you prove that then you must answer: what is the cause of that change?

The deceleration of the expansion rate was caused by gravity. The subsequent acceleration was caused by something that acts like a cosmological constant.

Originally Posted by ray

where does the necessary energy come from?

Well, I might start by saying that once an object is in motion it remains in motion, with no energy required. Gravity however, can change that motion, as can a cosmological constant.

Originally Posted by ray

how can it be greater that C?

How can what be greater than c? The expansion rate? Over what distance? You might ask Alan Guth that one - inflationary cosmology is what put the "bang" into the Big-Bang theory. But then again there has never been a claim that galaxies overtake photons, so no galaxy is moving faster than light. In essence, nothing is moving at all due to the expansion of the universe. The expansion does not "move" things around - it increases the distance between things, which is not necessarily the same thing.

Originally Posted by ray

why does after that speed decreases ?

That would be gravity again.

Originally Posted by ray

As far as expantion of space is concerned, you are behaving like the "last Japanese", because theorists have long acknowledged their mistake (I don't know if I am allowed here to quote another forum where even Dr Rocket is a member) but if you vist it, you'll see that the "award : best cosmologist of the year" has changed his tune and acknowledges that "space is not a substance, cannot expand"

We already know that. "Expanding space" is simply a useful analogy. Have you had a look at that "root of all evil" paper yet? It explains the current situation in cosmology in regard to this issue. As the paper will show you, although the universe seems to act as if space expands, this doesn't mean space has any properties of expansion in of itself.

As a gross simplification, I see the situation as this:
Observational evidence leads us to believe that the universe is expanding. Redshifts tell us that all galaxies at the larger distances are apparently (i.e. they seem to be, we cannot measure them directly) receding pretty much directly away from here. We assume we hold no special place in the universe, that that observers in other places would see a similar effect. Therefore, a model based on an explosion with a central focus doesn't work. A better model is one where the distance between things increases evenly at any given time. A model where, as an analogy, it is intuitive to consider that space expands.

So, the universe expands because space expands. Well, actually, it isn't space as such that expands, it is space-time as described by GR. Well, err, actually, space-time doesn't expand, but if you measure space-time using a certain convenient coordinate system, the space part expands. Hmmm, no that's not quite right either - to do the subject proper justice we have to discuss how the current cosmological model describes space-time using terms like foliations and spatial hyperslices with parameters acting as a surrogate for time (thanks Doc!), and in the end, the only way to really get a handle on it is to learn General Relativity!

So we end up with a situation something like this:

Originally Posted by ray

So, I have apologized for my reaction, I hope you acknowledge that your methodological, epistemological aproach to these issues is wrong.

I will acknowledge no such thing.

My approach comes from knowing the limits of science, what kinds of question a theory can answer through observational evidence, and what it might be legitimate to infer where we cannot observe.

Hi speed, I was not snarky, I know you are nice, in good faith. If you want to discuss we must follow a logical structure (I'm sure you (CAD) are familiar with flowcharts), please do not take offence any longer, my statements are facts without emotions.
I see you are repeating here, at last, what I said in my first post (#87) and you all blindly refused there: "nothing is proven in physics". (this behaviour is contradictory). I tried repeatedly to convince you that propositions of science are only falsifiable. When I said here "proven physics" I intended "scientific theories that have been confirmed by experiments over the span of centuries" that is real mainstream: the laws of motion, thermodynamics,gravity conservation of mass+energy and momentum etc.
What I tried to explain to you is that BB is not even a scientific theory, as it is a one-off event and all statements you make are not even falsifiable, whatever you say cannot even be confirmed by one miserable experiment, it's pure guesswork.
If your hypothesis has no internal contradiction as one probability of being true, if there is a single flaw, it is surely false.
If you have understood that, we can have a serious discussion, you will expose the point of view of your links, and I will make my objections, but you must concede defeat immediately, (without sending me to a link), when I point out a logical flaw or a contrast with mainstream.

You might argue: but nothing is sure, even in mainstream!, you are right, but you must question mainstream in real world with real experiments, not in a link, when you have ascertained that you are right, you change, update mainstream and only then you may use it in your guesswork.

I hope you are really competent in the doctrine, because it is a babel, you can read anything: BB happened in one place, no not in one place: everywhere; when I point out it is chaos you say: no, but everywhere means .. is a small space (#92), so in one place. That is chaos, not science, not fiction, not even magic. When I say you (from now on ) I mean you-cosmologists, if I say "magic, non-sense" do not take it personally, I am criticizing facts, statements made by them. If you subscribe to them, it is your problem. You can solve the problem admitting: you are right, it is non-sensical.

Now, if we want to make a serious debate we must star from the beginning, remember that your every statement has logical cogent implications and you are accountable for them in all the following discussion. If theory has a gap, you just say "nobody knows", if you are not sure ( you cannot know everything) you say "I don't know", always quote just my numbers in your answers, I'll refer to them them during the whole discussion.

1) I read cyclic modelbigbounce has been disproved because of entropy, is it true? someone considers it still valid? if yes
2) premise:BB happened after a bigcrunch. How do you describe the collapse of universe, at once or over billions of years. Isn't a collapse inprogress now in our universe?
2b) what is the result of the crunch, a BH? is it the same as the BH in BB, or if there is a crunch it is different. Size of universe is the same after the collapse or it shrinks ?

3) (no premise. Origin of BH unknown). BB theory: what existed at bang
a) a BH? mass: elementary particles (quark,gluon not proven) kg?,dimensions?,
b) time, space existed ? [or they began with BB? (dangerous option)]
c)universe:space greater than BH? if yes:size?
4)what is the cause of the explosion. (energy must come from inside)(it must be in all directions)

these are the fundamentals, your answers will determine everything else.

(btw: since you are an expert on GR, why don't you answer "can we survive..SR/GR" I'd like to know those answers, posters there do not even understand the questions. I discovered Harold is a great poster, do you agree? )

I wil ignore your demands....'you must admit defeat immediately' and other rules that you demand,this is not for you to dictate..
So to the nitty gritty;science is wrong and you want to show why..ok,fine ....then you want to know about pre BB,That, nobody can be clear of..good luck with that!
,

Originally Posted by ray

I see you are repeating here, at last, what I said in my first post (#87) and you all blindly refused there: "nothing is proven in physics". (this behaviour is contradictory). I tried repeatedly to convince you that propositions of science are only falsifiable. When I said here "proven physics" I intended "scientific theories that have been confirmed by experiments over the span of centuries" that is real mainstream: the laws of motion, thermodynamics,gravity conservation of mass+energy and momentum etc.

Actually, there is a distinction to be made here, and the situation is not quite as you are mispresenting it. What you actually said is that the Big-Bang is "unfalsifiable", and that is simply not true. There are many observations we might make that would falsify the Big-Bang theory.

Originally Posted by ray

What I tried to explain to you is that BB is not even a scientific theory, as it is a one-off event and all statements you make are not even falsifiable, whatever you say cannot even be confirmed by one miserable experiment, it's pure guesswork.

Your argument is fundamentally flawed as all these statements may be falsified by observation. The problem you have then is not with the Big-Bang theory, it is with all of cosmology and the way cosmology has to work.

Originally Posted by ray

If your hypothesis has no internal contradiction as one probability of being true, if there is a single flaw, it is surely false.
If you have understood that, we can have a serious discussion, you will expose the point of view of your links, and I will make my objections, but you must concede defeat immediately, (without sending me to a link), when I point out a logical flaw or a contrast with mainstream.

I would be interested to see what you think are logical flaws in the theory, as often there are objections are based on your our own notion of "common sense", which can sometimes be shown to be wrong by established scientific principles (like time-dilation or quantum entanglement, for instance). It is not my fault if you do not appreciate this.

Originally Posted by ray

I hope you are really competent in the doctrine, because it is a babel, you can read anything: BB happened in one place, no not in one place: everywhere; when I point out it is chaos you say: no, but everywhere means .. is a small space (#92), so in one place. That is chaos, not science, not fiction, not even magic. When I say you (from now on ) I mean you-cosmologists, if I say "magic, non-sense" do not take it personally, I am criticizing facts, statements made by them. If you subscribe to them, it is your problem. You can solve the problem admitting: you are right, it is non-sensical.

You interpret it as nonsensical, because you haven't recognised that the "one place" you keep referring to was, and always has been, the whole of the observable universe, rather than the whole of the whole universe! We cannot consider the universe from outside, and say "there it was!" We can only consider it from the inside, where the universe scales up in size, in all directions, directly away from here, whilst recognising that there must be more universe than we can detect, unless we live in a special place in the universe.

Your argument therefore is against cosmology in general, rather than the Big-Bang theory.

How can we ever perform an experiment about the origin of the universe, or physically measure whether the distant galaxies are increasing in distance over cosmological time scales? How can we ever perform an experiment on something we cannot reproduce in the laboratory, or in nature? Does that mean we should not use science to try to probe into conditions similar to those the theory predicts early on, using particle accelerators, and then apply our findings about fundamental particles to our model of the early universe? Are you saying that, unless we can directly measure something, we should not try to understand it? If that is the case, then you might as well ignore all of cosmology, which by definition is the attempt to understand the evolution of the universe, something we can never physically measure.

We can only make inferences from our observations of the distant universe, but one thing we know is that as we look across those distances, we are seeing the universe earlier in its history. We can measure the composition of objects using their spectra, and see how the contents of galaxies have evolved over time and how those spectra are shifted in wavelength with increasing distance. We can measure the predicted radiation that is left over from nucleosynthesis in the form of background radiation with a specific blackbody spectrum. We can also measure the heat of that radiation in earlier times, due to how it interacts with clouds of gas, and see that the data is consistent with that background radiation being hotter.

We see abundances of lighter elements in distant galaxies that seem consistent with a universe that was hotter, and denser. There is a lot of evidence that points towards our universe having been in a much hotter, denser state, and the background radiation predicted to be left behind after a phase transition in a hot dense universe. The evidence is compelling, but of course, not absolute. For some of these things there might be alternative possible explanations, but there doesn't seem to be a model that can be consistent with all of them, or to put it the other way round, no other model comes close to explaining all our observations as the "universe metrically expanding from a hot, dense state to a cooler state" model, otherwise known as the Big-Bang (I hate that term!), and formally known as the Lambda-Cold Dark Matter concordance model.



All Big-Bang theory is, in essence, is the observation of an expanding universe, with evidence for it previously being very hot and dense, and evidence that the expansion has changed from deceleration to acceleration. Everything else is increasingly speculative.

Originally Posted by ray

1) I read cyclic modelbigbounce has been disproved because of entropy, is it true? someone considers it still valid? if yes

As far as I am aware, the big-crunch and the big-bounce fell out of favour when we discovered that the expansion of the universe had stopped decelerating.

Originally Posted by ray

2) premise:BB happened after a bigcrunch. How do you describe the collapse of universe, at once or over billions of years. Isn't a collapse inprogress now in our universe?

No, rather than the expansion slowing down to a halt and then the universe starting to contract, we have observational evidence that the rate of expansion has started to accelerate, which implies the universe will never contract. That does not, however, preclude their being a previous crunch from which our universe is a bounce, but it seems to preclude our universe from partaking in another crunch or bounce, if you see what I mean.

Originally Posted by ray

2b) what is the result of the crunch, a BH? is it the same as the BH in BB, or if there is a crunch it is different. Size of universe is the same after the collapse or it shrinks ?

No the result of the Big Crunch was not a Black hole, and there is no black hole in the Big-Bang either. I dont know the answer to the second part.

Originally Posted by ray

3) (no premise. Origin of BH unknown). BB theory: what existed at bang
a) a BH? mass: elementary particles (quark,gluon not proven) kg?,dimensions?,

Big-Bang theory only talks of the evolution of the universe, not its origins. The singularity at the "beginning of time" is not the same thing as a black hole, at all. Nobody knows the mass of the whole universe, although I think there are estimates for our observable part of it.

Originally Posted by ray

b) time, space existed ? [or they began with BB? (dangerous option)]

They began with it, in as much as they are undefined at the singularity. We can only say that space and time existed after the Big-Bang. There is nothing dangerous about this option.

Originally Posted by ray

c)universe:space greater than BH? if yes:size?

Forget black holes, they have nothing to do with the Big-Bang. As soon as time is defined, i.e. when time>0, the whole universe could have been any size, even infinite in extent, and full of stuff, even though everything in our observable part of it was all contained within a small region at that time. At t=0 we find a singularity (which is generally taken to mean that GR breaks down at that point, rather than anyone thinking there was actually a thing called a singularity), so we can say nothing about size at t=0 as space and time are undefinable.

For there to be a black hole, there needs to be something else outside the black hole for it to be a black hole in relation to - an outside. A black hole is formed due to their being a gravity gradient that prevents possible escape, not from their being nowhere to possibly escape to.

Originally Posted by ray

4)what is the cause of the explosion. (energy must come from inside)(it must be in all directions)

Forget explosions - think in terms of expansion. An explosion requires a pressure differential, and there is no evidence for any "outside" of the universe for there to be differential in relation to. Nobody knows what caused the Big-Bang.

Considering the title of this thread, perhaps we might discuss the possible topologies for the universe? The possible "shapes"? Finite or infinite, bounded or unbounded, etc? The flatness of the universe?

because [QUOTE=SpeedFreek;285632]
I would be interested to see what you think are logical flaws in the theory, as often there are objections are based on 1) your our own notion of "common sense",
00 )How can we ever perform an experiment about the origin of the universe,?
2) We can only make inferences from our 2a)observations of the distant universe,
. The evidence is compelling, but of course, not absolute.

0) Big-Bang theory only talks of the evolution of the universe, not its origins.
Nobody knows the mass of the whole universe, although I think there are estimates for our observable part of it.

Originally Posted by ray

b) time, space existed ?)]

3) They began with it, .
0) so we can say nothing about size at t=0 as space and time are undefinable.

Originally Posted by ray

4)what is the cause of the explosion?
0) Nobody knows what caused the Big-Bang.

Considering the title of this thread, perhaps 4)we might discuss the possible topologies for the universe? The possible "shapes"? Finite or infinite, bounded or unbounded, etc? The flatness of the universe?

Hi speed, from now on I will not argue with you, I'll accept your statements, unless you require further explanation.
in 1) is the gist of your problem, you do not know the difference between commonsense and logic, and I can't teach you that! you contradict yourself, use fallacies and do not realize it.
in 00 you acknowledge what you ever denied and are denying here, in 2 you do not realize that inferences is logic., and that is what I have been talking for dozen of posts.
Now I'll tell you once more, if you do not get it , try a crash course on logic.:

All you can rely on is a bunch of radiation in different frequencies.Full stop. Ok? (the rest: dark night sky, isotropy, nucleosyntesis.... is delirium)
the same radiation tells you a straw is broken or there is "fake water", in real world you take the straw out of the glass, or travel on and find out there is no water, no palms, no dates, no nothing. In your case as you admit in 2a you can't. If I say from here that you are the victim of fatamorgana, my argument is more compelling then yours, because I can bring you many concrete examples and can even take you to the desert to see with your eyes, you cannot show me a precedend or a consequent of your inferences. If you do not understand that , it is your problem.

Now coming to your "compelling evidence" your "theory" you now nothing of the fundamentals that determine the current state of universe. The only thing you say
3) is an absolute non-sense, read other posts, because if time does not exists physical laws depending on time do not exist, like gravity. If space does not exist then particle cannot exist. This is not commonsense is physics and logic. Then come the logical compelling implications, I'll tell you only one because my time is wasted, these things, if you claim you know physics, you shold teach me:

if time,space begins at BB then =< space, time must be finite => universe cannot be infinite => and universe cannot be flat and => Ω cannot be =1 or <1

I hope you begin realize that issue is far more complicated and scientific than you imagined. I am talking science, you are talking optical illusion and fallacies.

4) of course we may, speed, because I like you, but you must change your tune, you must realize that you must be coherent, that every your proposition will be scrutinized and x-rayed.

now, I know everything you said so far, a couple of things I did not bother to check:

a) they say WMAP found out universe is flat. That makes me smile. But you tell me how would WMAP assess universe is curved? how do you see curved space?
b) I asked this question there, they thought it a joke, we got rid of trolls, now you tell me, why cant be universe a sphere?

c) what is concretely Hubble flow, outside a geometric formula. How is it related to hubble law, how can it increase distances without moving bodies?(that's what I call magic).
Now, be careful, because you are not talking anymore of the past, of the BB and cosmology, you are now in infested waters, as you are talking of real physics, what is happening now, right now, when you reply we'll be more distant by a few yards.
Explain how it is happening and how I can chek concretely your statements.

see you

Sorry, I cannot make head nor tail out of some of that post, what with the red, the numbers with letter suffixes, the zeroes, the double zeroes and the cross referencing - it is a total mess.

I must point out here that I am talking accepted science here - it is you who, unfortunately cannot understand it, as you are stuck with your notions of "logic" which you haven't even explained properly and at face value simply don't apply here. In order to understand these issues, you have to study them properly, which is why I reference the accepted scientific papers on these issues. If you refuse to read the links I have posted before, I can do no more for you, as all the words I can type will only be analogies.

And as for logical fallacies, you should understand that your arguments are from incredulity.

Originally Posted by ray

if time,space begins at BB then =< space, time must be finite

You make this assertion without saying why you think it is true. Whilst time must, by necessity, be finite if it had a beginning, why do think the same applies to space? Remember, we are talking about a universe that might well be much larger than the parts we have detected light from. If any space began with the Big-Bang, why is there a limit on how much space there could have been? As soon as we have space, why do think it would be limited to the space in only our observable part of the universe? When our observable universe was the size of, say, a grapefruit, it might have been part of a universe that was any size larger, or even infinite at that time.

Originally Posted by ray

=> universe cannot be infinite => and universe cannot be flat and => Ω cannot be =1 or <1

More blind assertions. Why can the universe not be infinite, in extent? Why can't the universe be flat? Please explain.

A finite universe can be flat too, you know.

When everything in our observable universe was contained in an area the size of a proton, why could the whole universe not have been any size larger?

A singularity can "blow up" into being either a finite or an infinite space. Why the objection to the second option? How is getting from a singularity to a finite universe any easier than getting from a singularity to an infinite universe?

And why not do your own research into how the WMAP team measured the flatness of the universe, at their website? Why not do your own research into how cosmology regards the "hubble flow" which is, of course, an analogy for the metric expansion of the universe as regarded by an observer that "moves with the expansion" and is thus at rest in relation to it and so would see all distant galaxies apparently receding from them in all directions, much like we do. After all, it is the only way you can be sure you are getting an accurate account, especially if I "don't know science".

All the links I have given you reflect the mainstream view in cosmology, but you will be looking for the "official science" website, of course. You might not trust wikipedia, but how about NASA?

Or perhaps you should pop into your local university and ask a professor.

Originally Posted by ray

Explain how it is happening and how I can chek concretely your statements.

Do your own research into how you can concretely check my statements.
It is the only way you can be sure you are checking them completely concretely.