What Existed Before the Big Bang?

[abitofnothingleft]

so today i was sitting in my philosophy class(dont worry this isn't really to do with philosophy) and we started talking about the universe and the "first creator." my teacher honestly believes that god is what made the universe move around and form into what it is now. but i want to proove her wrong. she understand that after the big bang theory everything was spread out because of the enormous amounts of force that followed the big bang but why was everything supposedly compacted together. like what pulled everything together in order for it to all be compacted into a gigantic ball of masses that one day exploded? how was everything pulled in together before the big bang?
i read this article ( http://ssscott.tripod.com/BigBang.html ) but i can't really seem to find anything on the pre-big bang times. if there are any suggestions you can offer or any sites or sources that i can try tolook up and find please tell me. either post it here or msg it to me. i appreciate it. thanks guys and dolls!

 

[Garth]

If the universe of space and time had a beginning then there is the question of First Cause.

1. One person might say, "God did it, He/She made the universe" - this leads immediately to the next question, "Who made God?"

2. Another person may say, "There is no God, the universe began as a random quantum fluctuation" - this leads immediately to the next question, "A random fluctuation in what? What/who made that?"

3. A third person (Stephen Hawking) may say, "The only initial boundary condition is there is no boundary condition, the 'origin' is actually like the North Pole, if you continue going backwards in time (northwards) you eventually begin to come forwards (southwards) on the other side of the universe (world). No agent is required as a First cause as there wasn't a First Cause" - this leads immediately to the next question, "Does this idea make sense?!"

4. A final person may say, "There is no 'beginning', there are an infinite number of universes, our universe was created out of, either the final crunch of a previous one or a black hole in another one" this leads immediately to the question, "Where are these other universes? Show me one!


If you ask why was the universe so compacted in the first place, the answer is all we do know is that if you trace back the expanding universe in time you inevitably tend towards a singularity called the Big Bang, with zero volume, infinite density and temperature, at which the known laws of physics break down. - And how!

In other words either of the above explanations may be equally considered 'scientific', there is no way of proving either one or disproving the other. You choose!

Garth

 

[setAI]

the universe is almost certainly one of an infinite number of bubbles in an ETERNAL sea of universes- a Multiverse-

Either Existence exists or it does not- if it does not it never will becasue there would be absolute nothingness and no being-ness would ever exist- if Existence does exist [which it does!] then there ALWAYS has been some existence in which universes emerge throughout eternity

an eternal cosmos could not have had a creator becasue it has always existed-

therefore the idea of a Creator of all things is necissarily shown to be impossible

 

[Mike2]

the universe is almost certainly one of an infinite number of bubbles in an ETERNAL sea of universes- a Multiverse-

Either Existence exists or it does not- if it does not it never will becasue there would be absolute nothingness and no being-ness would ever exist- if Existence does exist [which it does!] then there ALWAYS has been some existence in which universes emerge throughout eternity

an eternal cosmos could not have had a creator becasue it has always existed-

therefore the idea of a Creator of all things is necissarily shown to be impossible

As I understand it, inflation is an exponential expansion. And as exponentials go, you don't reach zero until you exponentiate to negative infinity. All this means is that creation came from extreme power from the infinite pass. And isn't that what is said about God: He has infinity power and exists from everlasting to everlasting?

 

[Adrian Baker]

You shouldn't bring god into Physics. All Physicists can do is describe the Universe as we see it and theorise about the past and the future. If you want a 'who' or 'why' stick to Theology or Philosophy!

As Garth put it above, there are various interpretations - You choose one that suits your personal philosophy!

 

[hellfire]

so today i was sitting in my philosophy class(dont worry this isn't really to do with philosophy) and we started talking about the universe and the "first creator." my teacher honestly believes that god is what made the universe move around and form into what it is now. but i want to proove her wrong. she understand that after the big bang theory everything was spread out because of the enormous amounts of force that followed the big bang but why was everything supposedly compacted together. like what pulled everything together in order for it to all be compacted into a gigantic ball of masses that one day exploded? how was everything pulled in together before the big bang?
i read this article ( http://ssscott.tripod.com/BigBang.html ) but i can't really seem to find anything on the pre-big bang times. if there are any suggestions you can offer or any sites or sources that i can try tolook up and find please tell me. either post it here or msg it to me. i appreciate it. thanks guys and dolls!

There is one question which cannot be handled within physics: what is the origin of the existence, or why is there something at all and not nothing. Physics describes always causal transformations from one physical state to another and "nothing" is no state nor has any potentiality of being transformed. Therefore, one is faced with the necessity of postulating the necessity of existence and not the posibility of deducing it. If one remains within the realm of physics one is forced to avoid this question. If your teacher was considering this point you will not be able to prove your teacher wrong.

On the other hand, if your teacher is arguing that starting from a given physical state, god acted to create the big-bang, then your teacher can be proven to be wrong (at least in principle). The physics to prove your teacher wrong and to describe these states and these causal transformations is still unknown today and you may only find some speculations (Hartle-Hawking model, Vilenkin-Linde model, models based on recent physics such as brane colissions, multiverses, etc.).

 

[marcus]

...

If you ask why was the universe so compacted in the first place, the answer is all we do know is that if you trace back the expanding universe in time you inevitably tend towards a singularity called the Big Bang, with zero volume, infinite density and temperature, at which the known laws of physics break down. - And how!

I agree with lots of what you say---and how you lay out the various viewpoints---but i think this is incomplete.

If you trace back using quantized General Relativity (any of several different alternatives) you don't get to a singularity.

You continue tracing back though a moment of high (but not infinite) density and high (but not infinite) temperature and you keep on tracing back. As you trace back into the contracting phase, the density and the temperature get less. This takes care of the horizon problem, that Inflation Scenarios were invented to solve.

If you use 1915 General Relativity as your model, to trace back with, then you do get to a singularity. But this is not inevitable because one is not forced to use 1915 Gen Rel. The fact that Gen Rel has singularities is widely believed to indicate that the theory is broken and people have been working for decades to fix the theory expecting that this would eliminate the singularities. It appears they now have a workable quantization, with a good classical limit, and that it has, as expected, fixed the "Big Bang" singularity. It is your choice how seriously to take the growing number of papers about this. I will get some references in case anyone wants to sample them.

What you get when you trace back in time depends on the model used to trace back with. it is no longer inevitable that one should use classical 1915 Gen Rel, so it is no longer inevitable that one gets to a singularity and has to stop tracing back.

A nice thing is that Loop cosmology has a good classical limit. It only disagrees for the first 10^-40 second of the expansion or so, after that it converges to classical or semiclassical behavior. So the quantized version only differs right around the big bang, which is where it needs to be different in order to eliminate the singularity and let you continue tracing back into the contraction phase.

Ashtekar and Bojowald have both discussed this convergence to the classical limit in various papers. there is, by now, a long list of papers by a lot of different researchers.

Your main point, Garth, is something else----physics is not about why/who.
I agree with that main point.
This business about the singularity is different. I contend that one does not inevitably encounter it.

If a person believes in Creator then there is no more reason for that Creator to have been around at the beginning of the observed expansion (at the socalled "Bang") than for Him to have been on hand in 1914 at the beginning of the First World War or for the first broadcast of "I Love Lucy". Theologically speaking, the classical ex-"Bang" is just another moment in history, as far as anyone knows.
The physics laws that apply to that moment should, as you indicated, be fascinating to discover, if we are even able to discover them! Certainly present laws do not cover those extreme conditions.

It is my feeling that the "Big Bang" should be scrubbed clean of any special theological interest so that one can study it dispassionately as one would anything else. More people are calling it the "Bounce" these days, which is probably more descriptive and less spiritually pornographic.

 

[Garth]

I actually said "inevitably tend towards a singularity". I shall be happy with quantized General Relativity theories when they become more testable and 'hone' down to a unique experimentally/observationally verified theory. Until then just wait and you will see a tide of fashion ebb and flow around the present alternatives.
I agree that GR is 'broken', but for other reasons!

Garth

 

[marcus]

good point,
I was not as alert to what you were actually saying
as I should have been

GR is still the dominant model and tracing back in time
does lead to the singularity which is present in GR

and the quantized (LQC) version has so far not been proven better
AFAIK it is only consistent
your guess is as good as mine as to when some quantized version
of the big bang will actually be subjected to experimental test
and how that will turn out
and the LQC version could be proven false and some entirely different quantized version of GR might then prevail----the tides of turbulent fashion that you mention.

I gather you expect that eventually some quantized theory will prevail which will eliminate the singularity and let one trace time back past the beginning of expansion. I shall be happy also when that happens.

 

[hellfire]

I gather you expect that eventually some quantized theory will prevail which will eliminate the singularity and let one trace time back past the beginning of expansion. I shall be happy also when that happens.

If time can be extended back or behind the big-bang, then, where should time begin? Or do this models claim that time has no beginning? But if time has no beginning, or let's say, if one can extend the causal chain back to infinity, one is faced with the problem of how handle the infinite chain of states: for any given state prior to present, one can always find a state preceding it, and, assuming a finite causal "speed" from one state to another, the question arises then how present came into being and how it is actually possible.

To me it seams that cosmology is forced to find a theory in which causality as well as time arise or emerge from an acausal and atemporal state and some laws acting on it, may be some law of randomness leading to a fluctuation on this initial state. Time would have no meaning before this state and no other state could have been previous. In some sense this is or was one of the beautiful ideas behind the big-bang model. Some other models based on recent physics, at least the one with the colission of branes (although I do only know the models from some "high level" press articles), extend the causal chain back behind the big-bang. This leads me to think that they cannot be based on fundamental theories.

 

[Chronos]

It is futile, if not pointless to pose a question such as 'what came before time?' and expect a scientific explanation. There is, however, an obvious answer - timelessness. Of course all known laws of physics break down in such a state. There is no causality without time and such a state is, by definition, chaotic. You can no more predict what might emerge from such a state than you can establish a causal link from what emerges to the state that preceeded its emergence.

Proclaiming the universe to be infinite is not an answer, it is evasion. Obviously the universe is not infinite in both size and age [re: Olbers Paradox]. While the jury is still out as to whether the universe is spatially infinite, the evidence is pretty compelling it is not infinitely old. When we look out at great distances, we see a universe that looks much different than the one nearby. It is filled with exotic objects and structures nowhere to be found around our neighborhood, but, remarkably similar to predictions of what a younger version of the universe should look like. Furthermore, in a universe infinitely old, where did all the hydrogen, etc, come from that fuels the stars we see today? How can you have an infinitely old universe that still has stars forming and burning without steady-state creation of new fuel? Now you are right back where you started. Who/what/where is all that new fuel coming from?

There is no escape from the creation issue, of something from nothing [at least nothing comprehensible to us]. You either accept that everything sprang from nothing a long, long time ago or that it has done so a little bit at a time for eternity.

 

[Gecko]

i think there's a theory in M theory that says we are on a giant brane, and that in a multiverse, two of these branes (one of them being ours) crash together over and over, the energy from the crash is the big bang. that's a pretty out there theory imo though lol. I've also heard it been said, and was stated above by Chronos, that it is pointless to think about the universe before the big bang because there was no time, and as chronos said, no causality.

 

[abitofnothingleft]

so basically no one knows the direct cause of the objects and everything in space compacting into one tight space and then exploding?

no one knows what was before the big bang? well i guess we wouldn't. its logical to assume we wouldn't...with those kind of temperatures any evidence of anything would just be incinerated(sp?) i guess

 

[cosmoboy]

Marcus is quite right, why we should use 1915 general theory of relativity. We do not know exactly what lies beyond the domain of GTR, but we are sure GTR must break somehow, because it predicts singularities. It is not difficult to guess that at the fundamental level nature of the universe must be quantum not classical. Much has been said about the LQG, string theories and quantum gravity, and these all theories avoid singularities. Just like singularities in QED were avoided by the use of renormalization, same thing could be done for the big bang also (I do not know how !). As far as time is concerned, I think time exists because we exist and we can feel the changes taking place in our environment. So the question of the birth of the time is basically the question of our existence. Time exists only there, where we can reach by any means. For example there is no way to communicate beyond our Hubble volume, so I do not think there is any meaning of time in that region. In case if we assume that the big bang did happen then it is fair to say that there was no space and time before the big bang. However, we can not see the big-bang (LIGO,LISA may help to see it through the gravity waves) so in place of big-bang being the birth time of time that point should be considered as the birth time of time from which we starts to observe the universe (some very large redshift). Let me again make it clear that time is more to do with our consciousness than the physical universe.
cosmoboy

 

[Chronos]

Marcus is quite right... In case if we assume that the big bang did happen then it is fair to say that there was no space and time before the big bang. However, we can not see the big-bang (LIGO,LISA may help to see it through the gravity waves) so in place of big-bang being the birth time of time that point should be considered as the birth time of time from which we starts to observe the universe (some very large redshift). Let me again make it clear that time is more to do with our consciousness than the physical universe.
cosmoboy

Apologies for editing your reply. I thought it was important to cut to the chase. Two people who have a deep understanding and appreciation for the issues you raise: Marcus and Nereid. Marcus has deep insights and knowledge. Nereid has a way with words that makes it understandable to the rest of us [not that Marcus does not, but Nereid explains things in a way I find more appealing]. I just take what I can from them and try to make it understandable to me. I have learned much from both of them. Let me say this, as well. You are right, consciousness does obscure the issue. Unfortunately, it is the only tool at our disposal.

 

[cosmoboy]

If time can be extended back or behind the big-bang, then, where should time begin? Or do this models claim that time has no beginning? But if time has no beginning, or let's say, if one can extend the causal chain back to infinity, one is faced with the problem of how handle the infinite chain of states: for any given state prior to present, one can always find a state preceding it, and, assuming a finite causal "speed" from one state to another, the question arises then how present came into being and how it is actually possible.

I do not understand this problem of handeling a chain of infinite states,
for this there are physical laws. Once causility is there then for a given past one can find a present with the help of physical laws.

To me it seams that cosmology is forced to find a theory in which causality as well as time arise or emerge from an acausal and atemporal state and some laws acting on it, may be some law of randomness leading to a fluctuation on this initial state. Time would have no meaning before this state and no other state could have been previous. In some sense this is or was one of the beautiful ideas behind the big-bang model. Some other models based on recent physics, at least the one with the colission of branes (although I do only know the models from some "high level" press articles), extend the causal chain back behind the big-bang. This leads me to think that they cannot be based on fundamental theories.

Could you please make it precise that what are the motivations for cosmolgy to find a theory in which time arise or emerge from an acausal and atemporal state. I understand this is what the big-bang model does.

 

[hellfire]

I do not understand this problem of handeling a chain of infinite states, for this there are physical laws. Once causility is there then for a given past one can find a present with the help of physical laws.

I am not really sure, but my impression is that it is not physically possible to have an infinite time (also I think it is not possible to have an infinite space). Strictly speaking it seams to me that infinite is neither a physical time interval nor a physical distance: if you substract any time interval to the infinite past, an infinite past still remains. For every time instant in past, you can always define a previous one, and, any time interval past between this point and present can be substracted without changing the fact that it existed an infinite chain of events. If causality works "step by step" then it seams to me that this cannot lead to any definite state in present. This is the reason I think a theory has to be found in which time and causality arise from an atemporal and acausal state. I might be wrong.

 

[cosmoboy]

I am not really sure, but my impression is that it is not physically possible to have an infinite time (also I think it is not possible to have an infinite space). Strictly speaking it seams to me that infinite is neither a physical time interval nor a physical distance: if you substract any time interval to the infinite past, an infinite past still remains. For every time instant in past, you can always define a previous one, and, any time interval past between this point and present can be substracted without changing the fact that it existed an infinite chain of events. If causality works "step by step" then it seams to me that this cannot lead to any definite state in present. This is the reason I think a theory has to be found in which time and causality arise from an atemporal and acausal state. I might be wrong.

As I understand, infinite is a relative concept. It is true that absolute infinite in not a physical physical thing. Some thing which picks such a large value that it looses its information and can be defined as infinity. Although there are observational evidencies (OLBER'S PARADOX) that the universe was not been here in the infinite past, even then this question remain unanswered that why big-bang happed when it happened not today, finally it leads us to the anthropic principle.

 

[Chronos]

Hellfire, for the same reasons you just stated, I agree. There is no way I can even imagine to escape any other conclusion. Footnote: The BB model does not attempt to explain what happened before time began, just what might have happened a Planck moment, or two, afterwards.

 

[marcus]

If time can be extended back or behind the big-bang, then, where should time begin? Or do this models claim that time has no beginning? But if time has no beginning, or let's say, if one can extend the causal chain back to infinity, one is faced with the problem of how handle the infinite chain of states: for any given state prior to present, one can always find a state preceding it, and, assuming a finite causal "speed" from one state to another, the question arises then how present came into being and how it is actually possible.

To me it seams that cosmology is forced to find a theory in which causality as well as time arise or emerge from an acausal and atemporal state and some laws acting on it,...

Hi hellfire, thanks for the thoughtful reply. I will make my response brief because I actually cannot comment on the philosophical questions you raise and i don't want to interrupt the interesting ongoing discussion you are having with Garth, Chronos, Cosmoboy, and others.
All I can say is that I see signs of an increasingly informed agreement (among a small group of experts I respect) that the Loop cosmology model consistently extends the causal chain back into a contraction phase prior to the "bounce" event---and provides both a clear description of the bounce and an explanation for the subsequent inflation that does not require fine-tuning or the introduction of extra stuff "by hand".

This does not address any of the philosophical issues---it just says that the beginning of the current expansion phase is not philosophically special. It certainly exhibits extreme and highly unusual conditions. Time may, at that junction, have been progressing in tiny Planck-size jumps----not approximable by a steady-running clock, indeed I suspect that no known clock could have existed apart from the process of contraction and expansion itself (which may have been occurring, as I mentioned, in tiny jumps). But though it was an unusual moment, when physical conditions were extreme, it does not seem permanently out of reach of study. Conditions prior to that moment may have left imprints which we will observe and which will eventually support inference about the prior contraction.

 

[Phobos]

Welcome to Physics Forums, abitofnothing left!

so basically no one knows the direct cause of the objects and everything in space compacting into one tight space and then exploding?

You are correct that the "cause" of the Big Bang is unknown (as outlined by all the responses you see here). Modern physics can only describe what happened in the universe back until a split second after the Beginning. There are some scientific ideas that try to explore the beginning/pre-beginning, but they lack evidence.

I just want to caution you against the mistaken notion that the Big Bang was an explosion of stuff into empty space. It wasn't. It was the rapid expansion of the entire universe. The universe didn't explode INTO anything (that we know of). Right after the beginning, the universe was as edge-less and center-less as it is now (but the points of space were a lot closer together). The Big Bang "seed" (at Time = 0) cannot be described by modern physics (we're still working on that one!).

my teacher honestly believes that god is what made the universe move around and form into what it is now.

Which is fine as a statement of faith, but not as a scientific fact/theory.

but i want to proove her wrong.

You won't be able to do that, but you can show her that there is no scientific evidence to support that idea. Or you could meet in the middle and agree that God made the natural laws that the universe follows.

she understand that after the big bang theory everything was spread out because of the enormous amounts of force that followed the big bang

Which is a misunderstanding.
"Stuff" was already present throughout the universe (stuff = a soup of fundamental particles/energy) right after the Big Bang. With the rapid expansion of space, that stuff was thinned out and cooled off. Eventually, 300,000 years later, it cooled enough to form atoms. Gravity pulled atoms into stars and galaxies...throughout the universe.

 

[Garth]

There have been many good points made in this thread.
May I add a few comments?
Astrophysics and Cosmology are disciplines that are a fruitful union of theory and observation. Often theories cannot be directly tested in a laboratory, but predictions can be made from those theories and observations may verify or falsify them.
The art is in understanding what 'goes on out there' by understanding what 'goes on down here'. It is the physics of the laboratory applied to the stars, in other words: astrophysics.

In cosmology we approach 'the edge', (using the word figuratively and not literally!) and the further we go the more we rely on theory and the less on verifying observations.

The boundary of what can and cannot be observed keeps moving 'outwards', but it seems unlikely to be able to reach beyond the Big Bang itself (whatever that might turn out to be)

So we may have many theories about 'eternal inflation', a 'multiverse' or 'bouncing branes', or Hawking's idea that as you go back in time the conical point of space-time, expanding spherical symmetrically from a singularity, actually becomes like a 'ball-point' pen and the end is like the North Pole. Carry on going northwards and you end up coming southwards on the other side. There is no singularity, there is no beginning.

All these ideas are intriguing, but it is at present impossible to prove anyone of them, or even to verify them, and it always may be so. As such there is a big question as to their standing as a scientific theory. They are possible explanations, that stand alongside other equally valid ones, you cannot tell which is correct, all you can do is test to see whether they are self consistent and consistent with the cosmological data our observations have harvested.

Finally when we talk about space and time we are used to thinking about measurable quantities, time, length, volume etc. In particular we think in terms of 10^-33 second or so, but we also have to ask, "What is a second?" In other words what do we mean by a fraction of a second at a time when there were no clocks to measure it?

Just a few thoughts.

Garth

 

[turbo]

Proclaiming the universe to be infinite is not an answer, it is evasion. Obviously the universe is not infinite in both size and age.

Obviously? Did I miss another breathless announcement yesterday proclaiming the end to all cosmological quests? The universe may in fact be infinite in extent, and may in fact be steady-state in nature and infinite in age. Strict interpretation of redshift as evidence of cosmological expansion may lead us to extrapolate back toward a big bang "singularity", but this interpretation of redshift may not be accurate. Quantum theory tells us that "empty space" is anything but empty, so while redshift may be roughly proportional to distance in most cases, it may have a rational explanation that does not require the expansion of the entire universe. The SBB theory is in vogue now, but it was not always so, and it may fall out of favor again (perhaps fairly soon).

While the jury is still out as to whether the universe is spatially infinite, the evidence is pretty compelling it is not infinitely old. When we look out at great distances, we see a universe that looks much different than the one nearby. It is filled with exotic objects and structures nowhere to be found around our neighborhood, but, remarkably similar to predictions of what a younger version of the universe should look like.

In fact, when we look out to very great distances, we see very large well-formed galaxies and systems of interacting galaxies, not unlike those in our own neighborhood. This poses a problem for the Heirarchical model in standard cosmology, which says that smaller, simpler structures interacted and evolved over time into larger, more complex ones. Even though we can look VERY far back, we have not yet discovered an epoch dominated by small star clusters or proto-galaxies.

Furthermore, in a universe infinitely old, where did all the hydrogen, etc, come from that fuels the stars we see today? How can you have an infinitely old universe that still has stars forming and burning without steady-state creation of new fuel? Now you are right back where you started. Who/what/where is all that new fuel coming from?

There is no escape from the creation issue, of something from nothing [at least nothing comprehensible to us]. You either accept that everything sprang from nothing a long, long time ago or that it has done so a little bit at a time for eternity.

You have answered your own question. A steady-state universe in which matter is continually created is a viable model. We discussed this in another thread, relative to the preferential infall of anti-particles of ZPE virtual pairs. If the Athena project shows that the gravitational infall rate of antimatter is significantly higher than that of matter, cosmologists are going to have to carefully reconsider the work of Fred Hoyle and others, because that would supply a mechanism for continuous creation of matter. The Big Bang may seem to be the only game in town, now, but just wait a while.

 

[turbo]

Finally when we talk about space and time we are used to thinking about measurable quantities, time, length, volume etc. In particular we think in terms of 10^-33 second or so, but we also have to ask, "What is a second?" In other words what do we mean by a fraction of a second at a time when there were no clocks to measure it?

True, extrapolating back toward a singularity is fraught with difficulties, not the least of which is trying to express things in relative terms of length and time in a domain where these measures become meaningless.

 

[Chronos]

Proclaiming the universe to be infinite is not an answer, it is evasion. Obviously the universe is not infinite in both size and age.

Obviously? Did I miss another breathless announcement yesterday proclaiming the end to all cosmological quests?

No, you missed the reference to Olber's Paradox.

The universe may in fact be infinite in extent, and may in fact be steady-state in nature and infinite in age.

This ignores Olber's Paradox, which I think deserves an explanation. [Note: links below regarding Olber's Paradox are for the curious, but feeling lazy at the moment]
http://zebu.uoregon.edu/~imamura/123/lecture-5/olbers.html
http://www.bluffton.edu/~bergerd/NSC_111/cosmology.html

In fact, when we look out to very great distances, we see very large well-formed galaxies and systems of interacting galaxies, not unlike those in our own neighborhood..

What we see is galaxies more mature than expected for their apparent age. That is well known and generally believed to indicate more rapid star formation than expected in the early universe. There is, however, evidence these galaxies, while not unlike, have distinct differences from those in our own neighborhood.

This poses a problem for the Heirarchical model in standard cosmology, which says that smaller, simpler structures interacted and evolved over time into larger, more complex ones. Even though we can look VERY far back, we have not yet discovered an epoch dominated by small star clusters or proto-galaxies.

This is not a problem for the hierchical model, just the existing model. There is a mountain of evidence the universe on the whole appears much different at high v low redshifts. Of course it is entirely reasonable to expect examples:

http://arxiv.org/abs/astro-ph/0410094
From z>6 to z~2: Unearthing Galaxies at the Edge of the Dark Ages
Excerpt "A clear trend of size with redshift has been identified"

http://zebu.uoregon.edu/1997/ph410/l22.html
The source has this to say about the Lyman alpha forest
"There is strong evolution with redshift!"

Hubble Ultra Deep Field
http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/07/text/
And there is this from the Hubble site commenting on the Hubble Ultra Deep Field data
"there is a zoo of oddball galaxies littering the field. Some look like toothpicks; others like links on a bracelet. A few appear to be interacting. Their strange shapes are a far cry from the majestic spiral and elliptical galaxies we see today. These oddball galaxies chronicle a period when the universe was more chaotic. Order and structure were just beginning to emerge."

 

[Garth]

Olbers Paradox: If the universe were
1. Infinite in extent AND
2. Infinite in age AND
3. Static
as the pre-GR universe was thought to be then the sky should be burning bright.

The universe could be infinite in extent AND infinite in age AND expanding, such as Hoyle's Steady State model {R = R₀exp(Ht)}, and the sky could still be dark at night. It would have a very slight glow that Hoyle tried to identify with the CMB - but he could not get it to work properly.

Garth

 

[Chronos]

A static model of the universe? Please explain what 'static' means. It is not a term I am familiar with as a premise under Olber's Paradox. I also do not understand how it relates to GR. It is, of course, possible the universe could still be infinitely old and large. The only problem is explaining why observational evidence suggests otherwise.

 

[dawhitedwarf]

there's that word again, redshift.

any flaw , even slight, with the way we interperet redshift , is going to make us need to reevaluate a lot of what we think we know.

time-distance ect

i agree the sbb is broken, like so many other theories.
seems we are in the trend of *if it don't count up, patch it*.
that isn't science , that's desperation.

Great thread guys , and some great points being made.

thx , enjoyed it lots.

 

[turbo]

A static model of the universe? Please explain what 'static' means. It is not a term I am familiar with as a premise under Olber's Paradox. I also do not understand how it relates to GR.

First off, Wilhelm Olbers' paradox arose in part due to some factors of which he was unaware. 1) Stars and galaxies do not have infinite life-spans. 2) Objects that are very far from us tend to have redshifts roughly proportional to their distance, meaning that the light from very distant objects is redshifted out of the visual wavelengths, into the infrared and below. The universe actually quite uniformly luminous in all directions, but not in the visual wavelengths.

You should be very familiar with the concept of a static universe in relation to GR. Einstein introduced the cosmological constant to produce a static universe, when his "curved space-time" model of gravitation seemed to require that the universe collapse in upon itself. This is fairly central to the application of GR to cosmology. There are lots of papers and web pages that discuss the history of the CC in this context.

It is, of course, possible the universe could still be infinitely old and large. The only problem is explaining why observational evidence suggests otherwise.

The observational evidence is neutral on this subject. It is the interpretation of the observational evidence that leads many to believe that our universe must be expanding and finite in age. This "standard" model hinges on the belief that the redshift/distance relationship must be evidence of cosmological expansion. Extrapolating backward at the perceived rate of expansion gives a limiting age of the SBB universe. Interestingly, unless our understanding of stellar evolution is very wrong, there are stars in the globular clusters surrounding our Milky Way that are older than the universe.

Edwin Hubble himself was very leery of the interpretation that redshift is due to cosmological expansion. So were/are many other observational astronomers. SBB has had a long run, but it is getting very top-heavy with ad-hoc corrections, constants, finely constrained initial conditions, etc.

 

[Garth]

A static model of the universe? Please explain what 'static' means. It is not a term I am familiar with as a premise under Olber's Paradox. I also do not understand how it relates to GR. It is, of course, possible the universe could still be infinitely old and large. The only problem is explaining why observational evidence suggests otherwise.

Olber's Paradox was a paradox in the pre-GR days when it was generally thought that the universe was eternal and static on the largest scales. The version I gave in my post #26 is the standard argument. Newton had argued that if the universe was not infinite then everything would collapse down under mutual gravitational attraction; therefore it had to be infinite! Olbers argued otherwise.

The expanding universe resolved the paradox.

However there are other ways of interpreting the data, although these are not very popular today. One possibility is the stationary universe, I started a thread on it referring to a recent eprint by Peter Ostermann who is working on it, but nobody wanted to comment!

Hoyle also like to consistently push for a non BB model and gave various modified versions of his Steady State theory once the CMB scuppered it. One of these was a Mass Field Theory, which was static and therefore could be constrained by Olbers Paradox. This was one of his conformal gravity theories in which the (rest) mass of an atom varies across the space-time domain. There is a membrane (nothing to do with Brane theories) at which the mass is zero, here photons thermalise with the (infinite sized) atoms and that becomes the surface of last scattering of the CMB in the standard theory. As we look towards this membrane atomic masses decrease and therefore the light they emit is progressively red shifted.

Garth

 

[turbo]

Hubble Ultra Deep Field
http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/07/text/
And there is this from the Hubble site commenting on the Hubble Ultra Deep Field data
"there is a zoo of oddball galaxies littering the field. Some look like toothpicks; others like links on a bracelet. A few appear to be interacting. Their strange shapes are a far cry from the majestic spiral and elliptical galaxies we see today. These oddball galaxies chronicle a period when the universe was more chaotic. Order and structure were just beginning to emerge."

We should parse these public announcements with care. The HUDF samples a tiny area of the sky relative to our immediate neighborhood, but that translates into a huge cross-section at great distances, and the resulting enormous volume contains countless galaxies. Of course, at great redshifts, there will be a lot of anomalous galaxies. That is because at very large redshifts, the galaxies most visible to us will be ones that are quite disturbed, such as those that are exhibiting energetic starburst events. Such galaxies will be highly over-represented in any survey in which we are "pushing the envelope" in regard to detector sensitivity, while quieter, more normal galaxies may fail to rise above the threshold of system noise. This over-representation of more energetic galaxies at redshift z~x is an example of a "selection effect".

 

[meteor]

if there are any suggestions you can offer or any sites or sources that i can try tolook up

if you're a fan of string theory, try this
"Born-again braneworld"
http://arxiv.org/abs/gr-qc/0301126
A scenario in which two branes collide just before Big Bang, and then reemerge with their tensions changed. It's very similar to the ekpyrotic scenario, if you have heard of it

 

[Chronos]

Olber's Paradox was a paradox in the pre-GR days when it was generally thought that the universe was eternal and static on the largest scales. The version I gave in my post #26 is the standard argument. Newton had argued that if the universe was not infinite then everything would collapse down under mutual gravitational attraction; therefore it had to be infinite! Olbers argued otherwise.

The expanding universe resolved the paradox.

However there are other ways of interpreting the data, although these are not very popular today. One possibility is the stationary universe, I started a thread on it referring to a recent eprint by Peter Ostermann who is working on it, but nobody wanted to comment!

Hoyle also like to consistently push for a non BB model and gave various modified versions of his Steady State theory once the CMB scuppered it. One of these was a Mass Field Theory, which was static and therefore could be constrained by Olbers Paradox. This was one of his conformal gravity theories in which the (rest) mass of an atom varies across the space-time domain. There is a membrane (nothing to do with Brane theories) at which the mass is zero, here photons thermalise with the (infinite sized) atoms and that becomes the surface of last scattering of the CMB in the standard theory. As we look towards this membrane atomic masses decrease and therefore the light they emit is progressively red shifted.

Thanks Garth. I wasn't quite on the same page with respect to a static universe. It also occurred to me a static universe is implied by Olber's premise of an infinitely old universe. An expanding universe suggests the universe has a finite age because if you run the 'movie' backwards, it should collapse. I can't think offhand of any way to avoid that result without causing significant problems for modern cosmology. And that is a possibility that cannot be ignored. Clearly, much remains unexplained and it would be no surprise if new chapters are added to the book of theory, or existing chapters rewritten. Perhaps some older, out of favor ideas will be resurrected, although I suspect it will be something more surprising.

Apparently I missed your thread on the Ostermann paper. Give me a link, I would like to give it a look.

One of the problems I see with theories of mass, or gravitational constants that vary over time is the effect on stellar evolution. It is not clear how this can be reconciled with observation. Stars would require more atoms [mass] when young to initiate fusion. As they aged and their atoms got heavier, they would evolve at an accelerated rate. Not only would they run out of fuel sooner than expected, they would progressively collapse over time ending up as black holes.

 

[Garth]

Apparently I missed your thread on the Ostermann paper. Give me a link, I would like to give it a look.

https://www.physicsforums.com/showthread.php?t=51024.

One of the problems I see with theories of mass, or gravitational constants that vary over time is the effect on stellar evolution.

In the Einstein conformal fame of SCC stellar evolution is unchanged, in the Jordan conformal frame G and M vary but such that GM is constant. Stellar evolution and all astrophysical processes are unchanged except for the time scale.

Garth

 

[fizzzzzzzzzzzy]

I agree with your teacher because that is the only one of the chocies that doesn't continue the question

 

[turbo]

I agree with your teacher because that is the only one of the chocies that doesn't continue the question

Your choice (God did it) is comfortable to many for the reason you cite. It is unsatisfactory to many others for these reasons:

Who made God?

Where did God reside before he created our universe?

Why are the rules of our universe (the principles of its structure and interactions) coherent and discoverable? This should not necessarily be the case if the universe was created by a capricious God.

What existed before the universe?

There are a lot more metaphysical questions, but I will leave you to parse these before spending a lot of time posing them.

 

[Garth]

Your choice (God did it) is comfortable to many for the reason you cite. It is unsatisfactory to many others for these reasons:

Who made God?

Where did God reside before he created our universe?

Why are the rules of our universe (the principles of its structure and interactions) coherent and discoverable? This should not necessarily be the case if the universe was created by a capricious God.

What existed before the universe?

There are a lot more metaphysical questions, but I will leave you to parse these before spending a lot of time posing them.

Although these questions can only be answered by a ‘work of faith’, i.e. you cannot use scientific observations to get a handle on them; the fact that the Big Bang or Black Hole singularities present a barrier or horizon for scientific observations has the consequence that much of modern cosmological theorizing (the multiverse, Smolin’s evolutionary cosmology etc.) may equally be thought of as a 'work of faith'!

Garth

 

[jbaxter1701]

Escape from a Dying Universe

Hello,

I am reading -- and re-reading Dr. Kaku's article in the December Discover magazine "How to Survive the End of the Universe". It is fascinating to ponder the possibility that hyper-advanced civilizations could develop incredible technologies that would enable them to move the essence of their intelligence - or in fact their civilization itself - to another universe in the Multiverse.

"Even if... (an artificial wormhole) ..."were subatomic... it might still be possible to inject enough information through the wormhole via nanotechnology to re-create the entire civilization on the other side".

The thought that came to mind upon reading this was -- what would this look like from "the other side"?

Suddenly, and seemingly from nothingness, there is information and energy. In a deep and mysterious process involving nanotechnological interactions, matter begins to form. Structure is created by the incoming information. A new Universe forms, starting from a tiny point in space. Or perhaps, space and time itself form... as if from nothingness.

This is a new Big Bang. A new beginning...

This was described in poetic language in the Book of Genesis, and in the creation legends of many world religions. Perhaps these beautiful legends are an echo of a "racial memory" that is older than the Universe in which we live?

 

[aguy2]

If the universe of space and time had a beginning then there is the question of First Cause.

1. One person might say, "God did it, He/She made the universe" - this leads immediately to the next question, "Who made God?"



Garth

I propose that: "There is a high probability that we and the universe around us are involved in an ongoing, staged process of self-creation; wherein and whereby the creator of us and the universe around us is attempting to create itself." What do you think the probability is of this being the actual case?

aguy2

 

[Garth]

My own particular view is that the material universe is self creating, see my posts/thread on self creation cosmology. Whether this universe had a beginning or not depends on how you measure time, SCC has two conformal frames of measurement, in one the universe linearly expands from a Big Bang, whereas in the other it is static and eternal.

However the laws of such physics would be 'pre-exisitng' in some sense and therefore you may want to ask where do they come from? The answer to this question I believe is essentially metaphysical in nature.

Garth

 

[Garth]

We do also have a problem with language.

It is futile, if not pointless to pose a question such as 'what came before time?' and expect a scientific explanation.

The question is not only pointless and futile but it is also linguistic nonsense. The word "before" assumes a temporal order in which one event can be unambiguously ordered before another event. In other words it requires 'time' to exist in order to have any meaning at all!

It is therefore true to say that when you (the Creator God) had not made anything, there was not time, because time itself was of your making...
What then is time? I know well enough what it is, provided that nobody asks me; but if I am asked what it is and try to explain, I am baffled.

(St. Augustine. Confessions XI 14) AD 397/8