New Big Bang Theory

[SchrodingersCat]

Hi all,

Forgive me if this has already been addressed, but I'm having trouble wrapping my head around the inflation concept in one capacity.

As a poster mentioned previously, the force of gravity seems to be acting to pull galaxies and other objects together constantly. However, inflation theory posits that the "fabric" of space is (was?) expanding at a rate that is faster than the speed of light. Is this expansion uniform across the universe? To me, it seems that the expansion rate cannot be uniform at all points in space. If that were so, the rate of expansion would not allow for gravitational attraction, if the rate was greater than c. Let me know if I'm way off-base here.

 

[MeteorWayne]

You are confusing two different things. The Universe is expanding. That has been going on since nanoseconds after the big bang.

Inflation, is something entirely different. It occurred only during the first few nano seconds after the big bang, if it occurred. Hopefully we will learn more from the Plank satellite, which should add a lot of evidence for or against the inflation theory.

 

[SpeedFreek]

Hi all,

Forgive me if this has already been addressed, but I'm having trouble wrapping my head around the inflation concept in one capacity.

As a poster mentioned previously, the force of gravity seems to be acting to pull galaxies and other objects together constantly. However, inflation theory posits that the "fabric" of space is (was?) expanding at a rate that is faster than the speed of light. Is this expansion uniform across the universe? To me, it seems that the expansion rate cannot be uniform at all points in space. If that were so, the rate of expansion would not allow for gravitational attraction, if the rate was greater than c. Let me know if I'm way off-base here.

Hi there and welcome to the forum!

It all depends at what distance the apparent recession speed is c. Around 13.7 billion years ago, during the inflationary epoch, the rate at which two coordinates separated was faster than c at the smallest scale imaginable. 9 billion years ago, the rate at which two coordinates separated was faster than c at scales of over 5.7 billion light-years. Today, the rate at which two coordinates separate is faster than c at scales of around 14 billion light years.

At any given time during the history of the universe, the rate of expansion is considered to have been uniform.

Basically, the expansion rate started out incredibly fast but quickly decelerated and continued to decelerate for the next 8 billion years. The rate was so fast to begin with that gravity could not stop the universe from expanding, but gravity immediately started to slow down the expansion after inflation ended and for a long time we thought gravity would continue to do so, to some extent (which depends on the critical mass of the universe). We discovered quite recently that this doesn't seem to be the case - the rate of expansion stopped decelerating around 5 billion years ago and started to accelerate.

So I think you are correct in that, during the inflationary epoch, when the rate of expansion was faster than c down at the smallest scale, gravity could do nothing to stop it. Inflation is treated as if it starts and ends with a phase transition - much like the phase transitions from ice to water to vapour. In this case one theory is that as the universe expanded it was cooling, and when it reached a certain temperature it caused a phase transition in the vacuum itself!

(This is a very simplified explanation of inflation, by the way. I just hope it isn't too misleading!)

During inflation, the vacuum drove everything in the universe apart at incredible speed and then when the conditions were right, another phase transition occurred and inflation ended. The rate of expansion then continued, but at sub-light speeds at the smallest scales, so gravity could then start to do its work.

 

[xXTheOneRavenXx]

Basically, the expansion rate started out incredibly fast but quickly decelerated and continued to decelerate for the next 8 billion years. The rate was so fast to begin with that gravity could not stop the universe from expanding, but gravity immediately started to slow down the expansion after inflation ended and for a long time we thought gravity would continue to do so, to some extent (which depends on the critical mass of the universe). We discovered quite recently that this doesn't seem to be the case - the rate of expansion stopped decelerating around 5 billion years ago and started to accelerate.

So I think you are correct in that, during the inflationary epoch, when the rate of expansion was faster than c down at the smallest scale, gravity could do nothing to stop it. Inflation is treated as if it starts and ends with a phase transition - much like the phase transitions from ice to water to vapour. In this case one theory is that as the universe expanded it was cooling, and when it reached a certain temperature it caused a phase transition in the vacuum itself!

(This is a very simplified explanation of inflation, by the way. I just hope it isn't too misleading!)

During inflation, the vacuum drove everything in the universe apart at incredible speed and then when the conditions were right, another phase transition occurred and inflation ended. The rate of expansion then continued, but at sub-light speeds at the smallest scales, so gravity could then start to do its work.

Speedfreak, would this not be caused by a rapid "clumping" of matter throughout the universe around that era, as well possibly point to a temporary fluctuation in the amount of dark energy exertion on these celestial bodies during their development? rather than the "phase transitions from ice to water to vapour" theory? I mean it IS possible, however the amount of mass necessary to have such an impact on the expansion, I can't see being possible being based solely upon the ice, water, & vapour transition theory. Once matter began to form in more massive "clumps", more dark energy would have been required not only to continue the momentum of the expansion, but to accelerate it. So since about 5 Billion years or so isn't it theoretically possible, or even proven that we have a steady increase in the amount of dark energy throughout the universe? This to me would suggest as more matter throughout the universe is "clumped" together, somehow more dark energy is generated to compinsate.

 

[MeteorWayne]

Again, Raven you are confusing expansion with inflation. Inflation occurred for a few billionths of a of a billionth of a billionth of a billionth of a second.

Expansion (where gravity is significant) occurred after the first billionth of a billionth of a billionth of a billionth of a second, for the billions of years since then.

 

[xXTheOneRavenXx]

Yes, I understand that MeteorWayne. However couldn't mass distribution be the cause of the temporary decrease in expansion, and an increase in dark energy "rejuvenate" the expansion? Gravity could still exist, but on a more distributed scale before matter formed the celestial bodies we see today, thus a lesser affect in the earlier universe. The math would allow for a faster increase expansion with a less "solid" mass throughout the universe, would it not? and a more concentrated mass would slow it down? Greater dark energy, faster expansion is my own theory, but I think it has merit with current observations.

 

[SpeedFreek]

Speedfreak, would this not be caused by a rapid "clumping" of matter throughout the universe around that era, as well possibly point to a temporary fluctuation in the amount of dark energy exertion on these celestial bodies during their development? rather than the "phase transitions from ice to water to vapour" theory? I mean it IS possible, however the amount of mass necessary to have such an impact on the expansion, I can't see being possible being based solely upon the ice, water, & vapour transition theory. Once matter began to form in more massive "clumps", more dark energy would have been required not only to continue the momentum of the expansion, but to accelerate it. So since about 5 Billion years or so isn't it theoretically possible, or even proven that we have a steady increase in the amount of dark energy throughout the universe? This to me would suggest as more matter throughout the universe is "clumped" together, somehow more dark energy is generated to compinsate.

The ice-water-vapour was just an example of a phase transition - a substance that changes form under different conditions, it wasn't meant to mean anything else.

In the case of inflation, the substance was something that acted like a cosmological constant, a background effect. Something that is indeed rather like dark energy. In fact, there are some who speculate that dark energy is possibly the left overs from inflation, the same effect but at a drastically reduced, but non-zero value. If that were the case, then something caused this effect to be magnified by many magnitudes, for a fraction of a second during the inflationary epoch.

If dark energy acts like a cosmological constant, then you might indeed be right when you say dark energy is generated to compensate. If it is a background effect then it has the same value throughout that doesn't diminish with the expansion of the universe. We still, however, need a couple of phase transitions to take this background effect and magnify it by an incredible amount for the tiniest fraction of a second.

 

[ZenGalacticore]

I'm talking about the recently found increase in the rate of expansion of the Universe. If gravity was the only force operating, the expansion would be slowing as it apparently did for the first 8 billion years. It appears that since then, the expansion is speeding up; whatever is causing that is referred to as dark energy.

Do your homework, and look up the term.

I wasn't being a smarty-pants Wayne. Dark energy is a hypothesis at this point although we've inferred that some kind of mass/energy must be responsible for the accelerated expansion. They call it 'dark energy', but they don't really know what it is yet. I just don't think the acceleration is due to space repelling itself, that's all.
And since dark matter/energy makes up 74% or more of the matter/energy in the Universe-and is probably the cause of the acceleration- I'm a big fan of the oscillating Universe. Eventually, as the horizons of the Universe widen, all that dark stuff is going to pull it all back together in a 'big crunch'.
I mean for years, before all this dark stuff was inferred, many thought that the Universe would expand forever until matter itself decayed and all was left was dark and cold. Seems to me that if that were the case, it would have already happened and we wouldn't be here to ponder it. For all we know, their have been ten Quadrillion expansions and contractions, over a measurable but incomprehensible time scale.

 

[SchrodingersCat]

Hi all,

Forgive me if this has already been addressed, but I'm having trouble wrapping my head around the inflation concept in one capacity.

As a poster mentioned previously, the force of gravity seems to be acting to pull galaxies and other objects together constantly. However, inflation theory posits that the "fabric" of space is (was?) expanding at a rate that is faster than the speed of light. Is this expansion uniform across the universe? To me, it seems that the expansion rate cannot be uniform at all points in space. If that were so, the rate of expansion would not allow for gravitational attraction, if the rate was greater than c. Let me know if I'm way off-base here.

Hi there and welcome to the forum!

It all depends at what distance the apparent recession speed is c. Around 13.7 billion years ago, during the inflationary epoch, the rate at which two coordinates separated was faster than c at the smallest scale imaginable. 9 billion years ago, the rate at which two coordinates separated was faster than c at scales of over 5.7 billion light-years. Today, the rate at which two coordinates separate is faster than c at scales of around 14 billion light years.

At any given time during the history of the universe, the rate of expansion is considered to have been uniform.

Basically, the expansion rate started out incredibly fast but quickly decelerated and continued to decelerate for the next 8 billion years. The rate was so fast to begin with that gravity could not stop the universe from expanding, but gravity immediately started to slow down the expansion after inflation ended and for a long time we thought gravity would continue to do so, to some extent (which depends on the critical mass of the universe). We discovered quite recently that this doesn't seem to be the case - the rate of expansion stopped decelerating around 5 billion years ago and started to accelerate.

So I think you are correct in that, during the inflationary epoch, when the rate of expansion was faster than c down at the smallest scale, gravity could do nothing to stop it. Inflation is treated as if it starts and ends with a phase transition - much like the phase transitions from ice to water to vapour. In this case one theory is that as the universe expanded it was cooling, and when it reached a certain temperature it caused a phase transition in the vacuum itself!

(This is a very simplified explanation of inflation, by the way. I just hope it isn't too misleading!)

During inflation, the vacuum drove everything in the universe apart at incredible speed and then when the conditions were right, another phase transition occurred and inflation ended. The rate of expansion then continued, but at sub-light speeds at the smallest scales, so gravity could then start to do its work.

Awesome, thanks for the explanation! I wonder what the expansion rate actually was during the epoch of inflation...and how much expanding we have done since inflation ended.

 

[SpeedFreek]

Awesome, thanks for the explanation! I wonder what the expansion rate actually was during the epoch of inflation...and how much expanding we have done since inflation ended.

This is a little hard to explain in simple terms.

The universe as a whole could have been any size to begin with. We can theoretically track our observable universe back until it was incredibly small, but we don't know how much larger the whole thing was at the time. And this is without even thinking about inflation!

So, lets start off with the size of a universe you could observe if it had only existed for a fraction of a second. If information can only reach you at the speed of light, then when the universe was the merest fraction of a second old, your observable part of that universe would be incredibly tiny, something down at the planck scale.

Now inflation occurs. It is theorised that inflation expanded the size of (what was) our observable universe by a factor of at least 10^100 times the magnitude of Einsteins cosmological constant. I think I have heard that what started out as incredibly tiny could have ended up at least the size of our solar system! And the whole universe would still have been however much larger than that as it was to begin with.

But.... that inflation took a lot of what was previously our observable universe and put it well out of our reach. After inflation, we had a new observable universe. It was the size of a grapefruit! (Remember, this all happened in an unimaginably small fraction of a second - expanding from something at the tiniest scale to the size of a grapefruit easily exceeded an expansion rate of c)

So, everything in our observable universe today, which is around 92 billion light years across, was contained in the size of a grapefruit after inflation!

 

[DrRocket]

I'm talking about the recently found increase in the rate of expansion of the Universe. If gravity was the only force operating, the expansion would be slowing as it apparently did for the first 8 billion years. It appears that since then, the expansion is speeding up; whatever is causing that is referred to as dark energy.

Do your homework, and look up the term.

I wasn't being a smarty-pants Wayne. Dark energy is a hypothesis at this point although we've inferred that some kind of mass/energy must be responsible for the accelerated expansion. They call it 'dark energy', but they don't really know what it is yet. I just don't think the acceleration is due to space repelling itself, that's all.
And since dark matter/energy makes up 74% or more of the matter/energy in the Universe-and is probably the cause of the acceleration- I'm a big fan of the oscillating Universe. Eventually, as the horizons of the Universe widen, all that dark stuff is going to pull it all back together in a 'big crunch'.
I mean for years, before all this dark stuff was inferred, many thought that the Universe would expand forever until matter itself decayed and all was left was dark and cold. Seems to me that if that were the case, it would have already happened and we wouldn't be here to ponder it. For all we know, their have been ten Quadrillion expansions and contractions, over a measurable but incomprehensible time scale.

Dark energy, in the form of a cosmological constant, basically is space repelling itself -- a bit more rigorously stated perhaps, but that is what it basically is. So, you are really agreeing with the "dark energy" idea, which itself is just a placeholder until a more fundamental explanation can be created.

 

[DrRocket]

Hi all,

Forgive me if this has already been addressed, but I'm having trouble wrapping my head around the inflation concept in one capacity.

As a poster mentioned previously, the force of gravity seems to be acting to pull galaxies and other objects together constantly. However, inflation theory posits that the "fabric" of space is (was?) expanding at a rate that is faster than the speed of light. Is this expansion uniform across the universe? To me, it seems that the expansion rate cannot be uniform at all points in space. If that were so, the rate of expansion would not allow for gravitational attraction, if the rate was greater than c. Let me know if I'm way off-base here.

The inflation concept is based on some rather esoteric physics and requires the existence of a scalar field in quantum field theory, that has not been observed and has no counterpart that has been observed. For a good ciscussion of the idea the book The Inflationary Universe by Alan Guth, one of the creators of the theory, is highly recommended.

Inflation, at leat most versions of the theory, occurred for only a very short time following the big bang, and should not be confused with the ordinary and on-going expansion of the universe.

The expansion of the universe is uniform on very large scales, but not on local scales. The atoms in you, for instance, are gravitationally bound, and you are not being ripped apart by expansion.

 

[ZenGalacticore]

Excellent answer and reply DocRock. I read how dark energy/matter relates to the cosmological constant. But hasn't the cosmological constant itself been called into question lately?

This vaguely understood dark matter doesn't reside throughout intergalactic space in any appreciable amounts, does it? It's throughout and on the edges of known macro-structures(galaxies), and filaments of superclusters as far as I know. So to me, the idea of inter-galactic space( with a matter density of what, one hydrogen atom per/1000 or million cubic centimeters of inter-galactic space?, repelling itself seems a bit suspect.

Hey, I freely admit that I'm no phycisist, but other than gravity or inertia from the BB, what force could make space itself 'move' or contract in such a way?

Keep in mind I'm just asking. You seem to be knowledgeable on the subject.

[amend] I am understanding here. The dark matter-what ever it is- causes mutual space repulsion on a relatively localized level while at the same time, logically, this same unknown substance collectively, on the macro level, is what is causing and sustaining the accelerating expansion that we are now observing. Dazed and amazed, I am!

 

[DrRocket]

Excellent answer and reply DocRock. I read how dark energy/matter relates to the cosmological constant. But hasn't the cosmological constant itself been called into question lately?

This vaguely understood dark matter doesn't reside throughout intergalactic space in any appreciable amounts, does it? It's throughout and on the edges of known macro-structures(galaxies), and filaments of superclusters as far as I know. So to me, the idea of inter-galactic space( with a matter density of what, one hydrogen atom per/1000 or million cubic centimeters of inter-galactic space?, repelling itself seems a bit suspect.

Hey, I freely admit that I'm no phycisist, but other than gravity or inertia from the BB, what force could make space itself 'move' or contract in such a way?

Keep in mind I'm just asking. You seem to be knowledgeable on the subject.

[amend] I am understanding here. The dark matter-what ever it is- causes mutual space repulsion on a relatively localized level while at the same time, logically, this same unknown substance collectively, on the macro level, is what is causing and sustaining the accelerating expansion that we are now observing. Dazed and amazed, I am!

Don't confuse dark matter and dark energy. They are not the same thing. In fact they are quite different.

Dark matter is matter required to provide the gravity that is required, but for which no source is apparent, to explain how some galaxies are held together in the face of the rotation rates that are observed. It provides ordinary gravity, just more of it than is explainable without some additional matter existing. Dark matter is used to explain a problem tha that existed on the basis of observational evidence for quite a long time. There is some relatively recent data that supports the existence of this stuff, particularly some observed gravitational lensing. The effect of dark matter is attractive as for ordinary gravity. There are some candidate particles for dark matter, but they are rather exotic (the neutralino for instance, a supersymmetric partner to the neutrino and a particle that has never been detected and may or may not actually exist).

Dark energy is required to explain much more recent data (late 1990s) that the expansion of the universe is accelerating. Current cosmological models "explain" this with a postive constant, a "cosmological constant" in the Einstein field equations for general relativity. There is no more fundamental explanation. The result of this stuff, is a repulsive force. that exists throughout space-time, but is overcome locally by ordinary gravity. There are no good very candidates for dark enrgy, although I think Briane Greene has some fairly speculative explanation in terms of some sort of string theory. We are basically clueless regarding the origins of dark energy, assuming that it exists.

 

[origin]

The expansion of the universe is uniform on very large scales, but not on local scales. The atoms in you, for instance, are gravitationally bound, and you are not being ripped apart by expansion.

Not to be a stickler, but out atoms are not ripped apart becasue they are electrically bound. The earth, solar system, galaxy and galactic cluster is not being ripped apart because they are graviationally bound.

 

[DrRocket]

The expansion of the universe is uniform on very large scales, but not on local scales. The atoms in you, for instance, are gravitationally bound, and you are not being ripped apart by expansion.

Not to be a stickler, but out atoms are not ripped apart becasue they are electrically bound. The earth, solar system, galaxy and galactic cluster is not being ripped apart because they are graviationally bound.

Yes, you are right. The most important effect at that level is the electromagnetic force. By far.

The main point is that the expansion and accelerated expansion of space is just one effect among many, and it is countered by all of the forces that hold matter together.

 

[origin]

The main point is that the expansion and accelerated expansion of space is just one effect among many, and it is countered by all of the forces that hold matter together.

Absolutely, as I said I was being a stickler (aka 'prick').

 

[DrRocket]

The main point is that the expansion and accelerated expansion of space is just one effect among many, and it is countered by all of the forces that hold matter together.

Absolutely, as I said I was being a stickler (aka 'prick').

Not at all. Your comment was a good one. Quite valid. There is never need to apologize for being precise.

That comment added a significant piece of information for the many lurkers. I sincerely thank you for it.

 

[SpeedFreek]

In light of my earlier mention of phase transitions in this thread, I thought this article was interesting!

The Day The Universe Froze: New Model For Dark Energy

A cosmological phase transition — similar to freezing — is one of the distinctive aspects of this latest effort to account for dark energy — the mysterious negative force that cosmologists now think makes up more than 70 percent of all the energy and matter in the universe and is pushing the universe apart at an ever-faster rate.

 

[remindkevin]

SpeedFreak, that article was exactly what I was trying to say, but, being a regular guy could not, with my original idea. Of course, now I see, that many many others have thought this, but just as me, cannot provide real evidence, just theories. But I knew I wasn't imagining things; it made sense. Thank you for your input and encouragement. Man, took a lot to get that question answered "does this idea make sense and if it does is there anyone who would concur?" Thats all I wanted to know.

 

[astron_2007]

thebig bang theory is a much more complex hypothesis to explain because of not only due to change but evidence, i know this theory is speculation but my thought of how this universe caME TO BE WAS THAT: IT TENDED TO HAVE GERMINATED BY DARK MATTER THAT WAS BILLITH OF A BILLITH OF A CM IN IT DIAMETER BUT HAD A INNER PROCESS OF POSITIVE PARTICLES CALLED? PROTONS THAT WERE CHARGED TO A POINT OF CATLAYZATION RELEASING LARGE QUANITIES OF ENERGY, HAD A HIGHER GRADE OF LIGHT CALLED? PLANKS LIGHT THEN OVER THE EXPANDING PROCESS HAD BUILT UP SO MUCH ENERGY THAT THE ELEMENTS THAT HAD LIED BENEATH EACH MOLECULE THAT HAD BEEN PRESENT HAD THE TENDENCY TO HAVE COLLIDED CATALYZING THE PROCESS TO THE UNIVERSE. THIS A BRIEF DESCIPTION OF HOW, BUT NOT WHEN!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[SpeedFreek]

SpeedFreak, that article was exactly what I was trying to say, but, being a regular guy could not, with my original idea. Of course, now I see, that many many others have thought this, but just as me, cannot provide real evidence, just theories. But I knew I wasn't imagining things; it made sense. Thank you for your input and encouragement. Man, took a lot to get that question answered "does this idea make sense and if it does is there anyone who would concur?" Thats all I wanted to know.

I am happy to hear that, but hopefully you can forgive us, as the way you put it had us trying to understand how the whole universe could rotate around some sort of primordial ooze, rather than the rate of expansion being affected by a phase transition in the energy density of a quintessence field that pervades the whole universe.