What slowed or stopped inflation?

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Discussion Overview

The discussion revolves around the concepts of cosmic inflation, the nature of space, and the expansion of the universe. Participants explore the relationship between gravity and inflation, the idea of a "fabric" of space, and the implications of the balloon analogy in understanding these phenomena.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question whether gravity plays a role in cosmic inflation and its relationship to the expansion of the universe.
  • One participant proposes that the inflaton field underwent a phase transition, which initially drove inflation and later ceased to exert a repulsive force.
  • There is a discussion about the balloon analogy, with some arguing that there is no actual "fabric" of space, while others seek to understand what allows light to travel between gravitationally bound systems as they move apart.
  • One participant suggests replacing the term "fabric" with "geometry" to clarify the concept of spacetime, emphasizing that the effects observed are a product of geometry rather than a physical substance.
  • Another participant expresses confusion about the nature of space and how galaxies can move away from each other at speeds exceeding the speed of light, questioning the implications of an empty or newly created space.

Areas of Agreement / Disagreement

Participants express differing views on the nature of space and the balloon analogy, with no consensus reached on whether there is a "fabric" of space or how to conceptualize the expansion of the universe. The discussion remains unresolved regarding the implications of these concepts for understanding cosmic inflation and the behavior of light in an expanding universe.

Contextual Notes

Participants highlight the complexity of understanding curved spacetime and its effects, noting that these effects are not easily observable in everyday life. There is also mention of the limitations of Euclidean geometry in describing the universe's structure.

abbott287
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Was it gravity? Does the expansion of the universe have anything to do with the original inflation? One more. What actually is the "fabric" of space that is expanding? You always hear the balloon analogy, so what makes up the rubber of the balloon in real life? Thanks in advance for my uninformed questions. :shy:
 
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I believe the inflaton field that drove inflation underwent a phase transition, exerting a repulsive force and starting inflation, and upon reaching its ground state the repulsive force that it generated was no longer present.

http://en.wikipedia.org/wiki/Inflaton
 
abbott287 said:
Was it gravity? Does the expansion of the universe have anything to do with the original inflation? One more. What actually is the "fabric" of space that is expanding? You always hear the balloon analogy, so what makes up the rubber of the balloon in real life? Thanks in advance for my uninformed questions. :shy:

As for the balloon analogy, maybe this will help you understand that there IS no "fabric"

www.phinds.com/balloonanalogy
 
phinds said:
As for the balloon analogy, maybe this will help you understand that there IS no "fabric"

www.phinds.com/balloonanalogy


That helped explain a good part of it, thank you! If there is no "material" in real life that equals the balloon however, what is it that keeps light to c going between the gravitational bound systems, while those same systems can exceed c in their movement away from one another?. I thought it was the "fabric" of space time. The "fabric" was being stretched or created between the systems, while light had to pass "through" it. :confused: Again, your time and effort explaining this is greatly appreciated.
 
abbott287 said:
That helped explain a good part of it, thank you! If there is no "material" in real life that equals the balloon however, what is it that keeps light to c going between the gravitational bound systems, while those same systems can exceed c in their movement away from one another?. I thought it was the "fabric" of space time. The "fabric" was being stretched or created between the systems, while light had to pass "through" it. :confused: Again, your time and effort explaining this is greatly appreciated.

As I suggested in the balloon analogy discussion, I recommend that you google Metric Expansion
 
abbott287 said:
That helped explain a good part of it, thank you! If there is no "material" in real life that equals the balloon however, what is it that keeps light to c going between the gravitational bound systems, while those same systems can exceed c in their movement away from one another?. I thought it was the "fabric" of space time. The "fabric" was being stretched or created between the systems, while light had to pass "through" it. :confused: Again, your time and effort explaining this is greatly appreciated.

Replace the word "fabric" with "geometry" and you've got it. This is difficult to understand, but it is the geometry of spacetime that causes this. What this means is that as light travels across the universe, objects get further apart. Nowhere does it say that 'the fabric of spacetime itself' stretches, but the effect is similar to stretching a rubber sheet. Remember that. The effect is 'similar' to stretching a rubber sheet, yet it doesn't require that there actually be something there. That is perhaps the most confusing part. If nothing is there, what's bending, stretching, etc? Nothing. It is a product of geometry.

But what is geometry? Put simply, it is a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space
http://en.wikipedia.org/wiki/Geometry

Normal geometry you learn in school is called Euclidean Geometry, and it is only concerned with 'flat' space. Certain rules apply here, such as the fact that all angles of a triangle must add up to equal 180 degrees. However, non-Euclidean Geometry is different. It turns out that if you have a non-Euclidean space, a triangle may not have each angle add up to 180 degrees! The common example is how the equator and two lines of longitude can form a triangle with the north pole. It's a triangle all right, it's got 3 sides and 3 angles, but all three angles add up to more than 180 degrees. http://en.wikipedia.org/wiki/File:Triangles_(spherical_geometry).jpg
http://en.wikipedia.org/wiki/Non-Euclidean_geometry

However, while the example above puts the triangle on the surface of the Earth, nothing says that a surface is required. Space itself can simply work that way, regardless of whether or not it is made up of 'something'.

I think the main reason this is such a hard concept to grasp is that the effects of curved spacetime are not visible on our scale here on Earth. If everyone could see the effects of curved spacetime in their everyday lives there would be no question. No one asks why three angles of a triangle always add up to 180 degrees in flat space. No one thinks it's weird. It's simply accepted. Then when they hear that this geometry is wrong, they can't accept it. And that's what it boils down to. The geometry we all know and love is plain wrong. It's just accurate enough to use on our scale. (So I've been told by chronos or marcus or someone here at least)
 
Drakkith said:
What this means is that as light travels across the universe, objects get further apart. Nowhere does it say that 'the fabric of spacetime itself' stretches, but the effect is similar to stretching a rubber sheet. Remember that. The effect is 'similar' to stretching a rubber sheet, yet it doesn't require that there actually be something there. That is perhaps the most confusing part. If nothing is there, what's bending, stretching, etc? Nothing. It is a product of geometry.

But what is geometry? Put simply, it is a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space
http://en.wikipedia.org/wiki/Geometry

Normal geometry you learn in school is called Euclidean Geometry, and it is only concerned with 'flat' space. Certain rules apply here, such as the fact that all angles of a triangle must add up to equal 180 degrees. However, non-Euclidean Geometry is different. It turns out that if you have a non-Euclidean space, a triangle may not have each angle add up to 180 degrees! The common example is how the equator and two lines of longitude can form a triangle with the north pole. It's a triangle all right, it's got 3 sides and 3 angles, but all three angles add up to more than 180 degrees. http://en.wikipedia.org/wiki/File:Triangles_(spherical_geometry).jpg
http://en.wikipedia.org/wiki/Non-Euclidean_geometry

However, while the example above puts the triangle on the surface of the Earth, nothing says that a surface is required. Space itself can simply work that way, regardless of whether or not it is made up of 'something'.

I think the main reason this is such a hard concept to grasp is that the effects of curved spacetime are not visible on our scale here on Earth. If everyone could see the effects of curved spacetime in their everyday lives there would be no question. No one asks why three angles of a triangle always add up to 180 degrees in flat space. No one thinks it's weird. It's simply accepted. Then when they hear that this geometry is wrong, they can't accept it. And that's what it boils down to. The geometry we all know and love is plain wrong. It's just accurate enough to use on our scale. (So I've been told by chronos or marcus or someone here at least)


I understand the triangle part perfectly. I also would not call a "bent" or curved triangle a triangle either however. It would be a bent or curved triangle! I understand that the galaxies or bound systems are what are moving away from each other, but they are moving through "space" too, correct? Now if that is empty, or if its being created, so be it, but why can they move away from each other at faster than c? What is it that is keeping light at c, and not keeping the bound systems at c? Again, I really appreciate your time in trying to get it through my thick skull. :frown:
 
abbott287 said:
Now if that is empty, or if its being created, so be it, but why can they move away from each other at faster than c? What is it that is keeping light at c, and not keeping the bound systems at c? Again, I really appreciate your time in trying to get it through my thick skull. :frown:

Expansion. I don't know how else to say it. If things are very far apart, they simple recede from each other very quickly. Keep in mind that the light traveling in areas of space very far away from us is also receding greater than c. The universal speed limit does not apply to recession velocities due to expansion.
 
abbott287 said:
I understand the triangle part perfectly. I also would not call a "bent" or curved triangle a triangle either however. It would be a bent or curved triangle!

You can call it whatever you like, but mathematicians call it a triangle.

I understand that the galaxies or bound systems are what are moving away from each other, but they are moving through "space" too, correct?

No, not correct. If they were moving "through" space they would be subject to the limitaion of not exceeding c.

Now if that is empty, or if its being created, so be it, but why can they move away from each other at faster than c? What is it that is keeping light at c, and not keeping the bound systems at c? Again, I really appreciate your time in trying to get it through my thick skull. :frown:

Again, they are NOT "moving" in the sense that you mean. The distance are getting larger but nothing is moving.
 
  • #10
Drakkith said:
The universal speed limit does not apply to recession velocities due to expansion.

Why? What is IT that allows them to "move" (separate) apart faster than c?


phinds said:
You can call it whatever you like, but mathematicians call it a triangle.

I understand that. I guess my point was its easy to see what the cause is.



No, not correct. If they were moving "through" space they would be subject to the limitaion of not exceeding c.

So light is moving through "space" but the bound systems are not? Then what is it about "space" that is slowing light down that the bound systems do not have to adhere to? The "space" between systems is getting larger, so they are either moving through it, or its being created between them. If its being created between them, what the heck is it?



Again, they are NOT "moving" in the sense that you mean. The distance are getting larger but nothing is moving.

Then as I said above, space is being created between them, correct? If so, what is "space" ? (Thats the same "fabric" question again I know.) I really want to understand this. :redface:
 
  • #11
Its the same space, not newly created space. If you 'stretch' the coordinate system on a graph, have you created any additional coordinate space?
 
  • #12
abbott287 said:
Why? What is IT that allows them to "move" (separate) apart faster than c?

Geometry. Popular descriptions would say that they are riding space as it expands "beneath" them.

So light is moving through "space" but the bound systems are not? Then what is it about "space" that is slowing light down that the bound systems do not have to adhere to? The "space" between systems is getting larger, so they are either moving through it, or its being created between them. If its being created between them, what the heck is it?

Both light and matter are moving through space. Light always moves at c through space. BUT, they are both also affected by expansion, by the geometry of spacetime.

Then as I said above, space is being created between them, correct? If so, what is "space" ? (Thats the same "fabric" question again I know.) I really want to understand this. :redface:

The distance between them is increasing, but I wouldn't say that space is being created.
 
  • #13
Chronos said:
Its the same space, not newly created space. If you 'stretch' the coordinate system on a graph, have you created any additional coordinate space?

No, but you have stretched the paper or whatever the graph is on. So in reality, what is it you are stretching? What is that "space" made out of that is stretching?

Drakkith said:
Geometry. Popular descriptions would say that they are riding space as it expands "beneath" them.

Same question. What is it they are riding on that is expanding?? You say space, please tell me what that is made of that is expanding faster than c, and why can that "expand" faster than c?



Both light and matter are moving through space. Light always moves at c through space.


Totally understand that part of it. :smile:


BUT, they are both also affected by expansion, by the geometry of spacetime.

Thats where I am lost. If objects are receding from each other, more "space" is between them. If its being stretched, what actually is being stretched? What is the "material" that is being stretched? If nothing is being stretched, then what is being created between them as these things separate? If its space, what exactly is space?

The distance between them is increasing, but I wouldn't say that space is being created.


Something is either being stretched or being created, as the distance between them is now greater than when I first asked the questions yesterday! What is it?

I am not the smartest guy on the planet, but I should be able to grasp this. :frown:
 
  • #14
abbott287 said:
One more. What actually is the "fabric" of space that is expanding? You always hear the balloon analogy, so what makes up the rubber of the balloon in real life? Thanks in advance for my uninformed questions. :shy:

Expansion is not slowing down it is constantly increasing.
No one really knows what is the fabric of space.
We have a lot to learn, however just like in the UFO/alien domain there are a lot of guesses with no actual proof.
 
  • #15
abbott287 said:
No, but you have stretched the paper or whatever the graph is on. So in reality, what is it you are stretching? What is that "space" made out of that is stretching?

Nothing.

Same question. What is it they are riding on that is expanding?? You say space, please tell me what that is made of that is expanding faster than c, and why can that "expand" faster than c?

It isn't made of anything.

Thats where I am lost. If objects are receding from each other, more "space" is between them. If its being stretched, what actually is being stretched? What is the "material" that is being stretched? If nothing is being stretched, then what is being created between them as these things separate? If its space, what exactly is space?

The distance between them increases. You can say more 'space' is between them, but nothing requires that space be something that is being created.
Something is either being stretched or being created, as the distance between them is now greater than when I first asked the questions yesterday! What is it?

No, your belief that either something must be stretched or created is incorrect. That's the difficult part to understand. No, not understand, to believe. I believe you understand it perfectly fine, it's that you don't believe it's true, which leads you to dismiss the possibility that space isn't anything at all. Geometry itself, and by that I mean the way shapes are formed and how objects move in three dimensional space, can cause these effects.

Let me ask you this. Do you believe that something can be straight? Why? Is that not weird? Why is it like that? What if nothing could ever be straight, but only curved, is that really any weirder? What if the rules governing whether there could be straight lines or not actually changed over time? Does this require that 'something' be flexing, stretching, or similar? No. It only requires that the universe simply work that way.

Expansion is similar. To the best of our knowledge the rules that govern how objects interact with each other within space say that as the distance between them increases, they recede from each other with increasing velocity which is not limited by c. There is no answer to 'why' this is. That's simply the way it works.
 
  • #16
Drakkith said:
No, your belief that either something must be stretched or created is incorrect. That's the difficult part to understand. No, not understand, to believe. I believe you understand it perfectly fine, it's that you don't believe it's true, which leads you to dismiss the possibility that space isn't anything at all. Geometry itself, and by that I mean the way shapes are formed and how objects move in three dimensional space, can cause these effects.
If its nothing at all, then why is it a law that light can only go at c through it, (nothing) but the stars can move through it (nothing) at greater than c?? AHHH! The stars are not moving through it you say! Well they HAVE to be moving through it, (space) or creating it between them, or SOMETHING is happening to make the distance between everything greater. If its just a belief or a theory that this is what's happening, then I can understand, because no one understands, but it seems that you want to give one pretty much proven theory to light, and another law that bypasses that one to objects moving faster than that. They have to be moving (the word used is receding) to be getting father away from each other, or, something has to be growing between them.

Let me ask you this. Do you believe that something can be straight? Why? Is that not weird? Why is it like that? What if nothing could ever be straight, but only curved, is that really any weirder? What if the rules governing whether there could be straight lines or not actually changed over time? Does this require that 'something' be flexing, stretching, or similar? No. It only requires that the universe simply work that way.
No. I believe there is a reason why at times things could be straight, and at another time things could not be. Something has changed, and if we can't see it, then we just not have looked at it the correct way yet.

Expansion is similar. To the best of our knowledge the rules that govern how objects interact with each other within space say that as the distance between them increases, they recede from each other with increasing velocity which is not limited by c. There is no answer to 'why' this is. That's simply the way it works.
OK. This was all my mistake then. IMO, there is a very good reason for it IF that is indeed what is happening. We just have not figured it out yet. I thought this was all proven, which is my ingnorance. I thank everyone for their input, as now at least I know why I can't understand it! I do understand that that is what appears to be going on, but I think that figuring out what "space" really is will give the answer I am looking for.
 

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