The observable Universe and its shape

[tobyr65]

If the universe is expanding in all directions from one central point then how could the shape of the universe not be spherical?

The simple answer is the expansion outruns gravity.

If gravity is involved and it always is, expansion happens and then is pulled back by gravity so...sphere. Or balloon model. If expansion is too fast for gravity then straight as an arrow expansion...there is always room for both to happen. Spew a can of coke. Some coke will be on your hand and some will hit your mom across the room. Depends on the pressure applied to any given drop of coke. Ergo, some spherical curving bodies and some straight plain bodies of motion. Though eventually the straight bodies slow more and more, they never the less need never stop. They do not get pulled back as they our out of reach of a mass big enough to pull on them.

 

[PeterDonis]

The simple answer is the expansion outruns gravity.

No, the simple answer is that the universe is not expanding in all directions from one central point. The Big Bang did not happen at one particular location in the universe. It happened everywhere in the universe.

 

[tobyr65]

The Big Bang did not happen at one particular location in the universe. It happened everywhere in the universe.[/QUOTE]

Please list references. I can't reply to this theory as I haven't read it.

 

[newjerseyrunner]

Please list references. I can't reply to this theory as I haven't read it.

This is the accepted mainstream theory and the only one that fits the evidence of the universe appearing to be expanding uniformly everywhere.

 

[phinds]

Please list references. I can't reply to this theory as I haven't read it.

Then you should do some reading in the absolute basics of cosmology since this is one of the first things you will learn.

 

[tobyr65]

This is the accepted mainstream theory and the only one that fits the evidence of the universe appearing to be expanding uniformly everywhere.

Then it must have a name.

 

[tobyr65]

Then you should do some reading in the absolute basics of cosmology since this is one of the first things you will learn.

I'm a reader so this must be a communication thing. '...? is one of the first things you will learn. Say the theory name. Just say it.

 

[phinds]

I'm a reader so this must be a communication thing. '...? is one of the first things you will learn. Say the theory name. Just say it.

The Big Bang Theory.

 

[newjerseyrunner]

Then it must have a name.

It's called "The Big Bang Theory" and it's contrary to the other theory the "Steady State Theory." The Big Bang model replaced the steady state model in 1929 when Edwin Hubble concluded that the universe was expanding. The new theory predicted that the universe was slowly cooling and at some point in the past, there must have been a flash of light from the congealing of the first atoms. This was found in 1965 and is called the Cosmic Microwave Background.

 

[tobyr65]

The Big Bang did not happen at one particular location in the universe. It happened everywhere in the universe.

I thought you must have been talking about some theory other than TBBT.

The Big Bang Theory is the leading explanation about how the universe began. At its simplest, it talks about the universe as we know it starting with a small singularity, then inflating over the next 13.8 billion years to the cosmos that we know today. - See more at: http://www.space.com/25126-big-bang-theory.html#sthash.kvDniLFH.dpuf

 

[newjerseyrunner]

it starting with a small singularity

But keep in mind that singularity does not mean point, it may have even been infinite in size. Small is not the correct qualifier here, it was much denser. The OBSERVABLE universe was smaller.

 

[phinds]

I thought you must have been talking about some theory other than TBBT.

The Big Bang Theory is the leading explanation about how the universe began.

No, it most emphatically is NOT. It is the theory of how the universe evolved AFTER it began. The Big Bang Theory is silent on how things began and calls that a "singularity" meaning "the place where our model breaks down and we don't know what was really going on".

At its simplest, it talks about the universe as we know it starting with a small singularity, then inflating over the next 13.8 billion years to the cosmos that we know today. - See more at: http://www.space.com/25126-big-bang-theory.html#sthash.kvDniLFH.dpuf

Again, no. It does not specify the universe after the singularity as "small", just as "smaller than it is today". It might have been infinite then, in which case it is infinite now. "Small" doesn't enter into it.

Hard to see how your post #36 follows from any possibly interpretation of the Big Bang Theory.

EDIT: And to be totally correct, I really should not have said that The Big Bang Theory says that the universe was smaller in the past than it is today. That is a very common statement but not technically correct because if the universe was infinite then and now then it was not smaller then than now. What the BBT DOES say is that everything was closer together in the past than it is now.

 

[rede96]

EDIT: And to be totally correct, I really should not have said that The Big Bang Theory says that the universe was smaller in the past than it is today. That is a very common statement but not technically correct because if the universe was infinite then and now then it was not smaller then than now. What the BBT DOES say is that everything was closer together in the past than it is now.

Am I right in thinking that we can only measure the size of the universe and indeed the rate of expansion by observations made on physical objects we can detect. So aren't those measurements only telling us how that matter behaves? And therefore can we treat the space around that matter as a separate entity? If so can we have an infinite space but a finite area that the mater within that space spans?

 

[PeterDonis]

aren't those measurements only telling us how that matter behaves?

Directly, yes. Indirectly, no, because spacetime and matter are not independent, at least not according to our best current theory, GR. In GR, matter and spacetime are linked by the Einstein Field Equation, so if you know the matter is behaving a certain way, you also know the geometry of spacetime.

can we have an infinite space but a finite area that the mater within that space spans?

Not for the entire universe, no. More precisely, there is no solution of the Einstein Field Equation that has this property but also describes our observation of the universe as a whole. Solutions with this property (a finite extent of matter surrounded by an infinite empty space) work well at describing isolated objects like stars, planets, etc., but don't work well at describing the whole universe.

 

[phinds]

Am I right in thinking that we can only measure the size of the universe and indeed the rate of expansion by observations made on physical objects we can detect.

No, we cannot measure the size of the universe at all. It might be infinite.

And therefore can we treat the space around that matter as a separate entity? If so can we have an infinite space but a finite area that the mater within that space spans?

No, that would violate the Cosmological Principle and the tenet that the big bang expansion happened everywhere at once. "Everywhere" MEANS everywhere, not in some localized area.

 

[Droidriven]

Am I right in thinking that we can only measure the size of the universe and indeed the rate of expansion by observations made on physical objects we can detect. So aren't those measurements only telling us how that matter behaves? And therefore can we treat the space around that matter as a separate entity? If so can we have an infinite space but a finite area that the mater within that space spans?

No, the expansion is happening "faster" than the force of gravity can "grab" it and pull it back, as is the case with local groups being gravity bound and having no expansion.

To imply a finite expansion within an infinite space requires gravity being the dominant force to limit how "far" it can expand, that isn't the case, with no gravity to resist the expansion then, in theory, the expansion will continue to expand until the finite limit is reached (if the universe is finite) or continue to expand into infinity(if the universe is infinite). I've seen it discussed that expansion is "slowing" but I don't think that means it will ever stop because there is no verifiable opposing force to "stop" it. Expansion happens in the spaces that are void of "normal" matter(not counting the theorized dark matter which may or may not be the force causing the expansion, that is also debated), not within the boundaries of spaces occupied by accumulated matter, such as galaxies or groups of galaxies that are relatively close enough for gravity to be a factor in their associations.

If you are implying that space itself may be infinite but the "space" occupied by matter in the universe is a finite amount inside of a boundary within that infinite space, then, no would be the theorized/debated answer.

I'm not exactly clear on that because of a lot of things that are said, my understanding is that matter has always occupied the entirety of space from the beginning, only the expansion of that space has changed.

 

[tobyr65]

Phinds re: No. 47
OMG Okay, the singularity caused time space and matter and something from nothing….

Then a force pushed this something outward. Something we call a universe.

Most likely NOT an explosion, due to lack of spherical evidence. ( message 36)

I don’t want to discuss curvature vs. flat because curvature infers the universe runs into force obstacles to make it curve whereas the original ‘pushing’ gravity is snap back and did not stop the galaxies from separating much less causing the universe to sphere. It’s all guess work there for now anyway.

Still the outrunning gravity was my point for commenting on 36.

But tomorrow … and apparently yesterday, I thought partial spherical sounded right. I know I’ve seen something in the past inferring round and it may have been the microwave picture, you know the one it looks like the world globe laid out flat, but today I’m all for flat universe.

The ring of Saturn has a relatively minor thickness as it circles Saturn. Hell our universe is probably part of a ring around a giant we can’t see for all we know. Flat and moving at such a distance we can’t see the curve until its behind us a few billion years and appears as a ‘big bang’ instead of the density of objects in the distance.

Thank you for the reading you and the others made me do. I enjoy the reading. Yours and the professional findings out there to date.

 

[phinds]

Phinds re: No. 47
OMG Okay, the singularity caused time space and matter and something from nothing….

No, we don't know that. Again, "singularity" means we don't KNOW what was going on.

Then a force pushed this something outward. Something we call a universe.

Most likely NOT an explosion, due to lack of spherical evidence. ( message 36)

No, it was not "most likely not" an explosion, it was NOT an explosion. The evidence is clear on that.

I don’t want to discuss curvature vs. flat because curvature infers the universe runs into force obstacles to make it curve whereas the original ‘pushing’ gravity is snap back and did not stop the galaxies from separating much less causing the universe to sphere. It’s all guess work there for now anyway.

I have no idea what that means.

Still the outrunning gravity was my point for commenting on 36.

I think I get what you mean and although it's an awkward way to phrase it, it's correct. The accelerated expansion will not be reined in by gravity.

But tomorrow … and apparently yesterday, I thought partial spherical sounded right. I know I’ve seen something in the past inferring round and it may have been the microwave picture, you know the one it looks like the world globe laid out flat, but today I’m all for flat universe.

That picture, and no other picture, ever implied that the universe is spherical. That is a mis-interpretation on your part. The OBSERVABLE universe is spherical for sure and that may be where your confusion comes from.

The ring of Saturn has a relatively minor thickness as it circles Saturn. Hell our universe is probably part of a ring around a giant we can’t see for all we know.

This is nonsense and you need to be careful about that. It sounds like an unsubstantiated personal theory and the mods don't like those.

Flat and moving at such a distance we can’t see the curve until its behind us a few billion years and appears as a ‘big bang’ instead of the density of objects in the distance.

Once again, I have no idea what you are saying.

 

[tobyr65]

That picture, and no other picture, even implied that the universe is spherical. That is a mis-interpretation on your part. The OBSERVABLE universe is spherical for sure and that may be where your confusion comes from..[/QUOTE]

Are you saying spherical as in flat circle or as in ball shape?

 

[Droidriven]

Are you saying spherical as in flat circle or as in ball shape?

A flat circle and a sphere are two different things, a circle is 2D and a sphere is 3D.

And please learn to use the reply buttons correctly or learn how to properly quote if you are doing it manually. The way you are doing it forces anyone that is quoting what you post to have to edit our posts to correct how you quoted whoever you're responding to.

 

[tobyr65]

This is nonsense and you need to be careful about that. It sounds like an unsubstantiated personal theory and the mods don't like those..[/QUOTE]

It isn't nonsense nor is it my theory. I am not educated enough to have theories. We are in the middle of discussing universal shape. The universe does not appear ball shaped by the pix I looked up. Here is a cut and paste of the only three theories I've found:

Whichever one wins, right now, it appears that we are on a 'flat' area of the model.

I read something. If the reading makes sense to me I tend to believe it until I read something that contradicts it that makes more sense. Then I read something else. My thoughts change with new information that may or may not be correct. If my statements are unsubstantiated I can still point to who said/published it first.

Do I think the universe is a blip on a immeasurably large ring around an immeasurably large body? I have no opinion but, in the Journal of Cosmology, 2011, Vol 13, In press Journal of Cosmology.com February-March 2011, Joseph Rhawn, Ph.D. (Cosmology.com) makes a case for it (not his intention) when he writes on patterns. Infinity, Patterned Symmetry, Pythagoras, and the Black Hole at the Edge of the Universe ( 1. REPEATING PATTERNS ARE THE LAW OF NATURE & THE COSMOS).

But if you want to refer me to your proof, I'll read it.

I would use bold and underlines and italics in the last paragraph but I never learned to properly site references.

I am not being argumentative so much as explaining my remark... which you appear to have understood to have maybe been my personal theory ...and nonsense. I am not the best common correspondent much less the best scientific correspondent so I am truly not offended by our mutual confusion.

 

[tobyr65]

Re: number 55... ugh, I thought I had it!

 

[rootone]

Chill everybody.
We don't know if the Universe is infinite or not.
We do know that our observable universe is spherical and the centre of it is somewhere between your eyeballs.

 

[Droidriven]

Re: number 55... ugh, I thought I had it!

Lol, you did it again, look at your post.

I think you're improperly editing the posts you are quoting, make sure the QUOTE tabs are correct before and after the post you are quoting before you send.

 

[Droidriven]

the centre of it is somewhere between your eyeballs.

From whatever vantage point you are in at the time.

 

[rootone]

From whatever vantage point you are in at the time.

Yes, but 'frame of reference' is the usual term

 

[tobyr65]

I think you're improperly editing the posts you are quoting, make sure the

if I do this correctly the 'Lol, you did it again, look at your post.' will be missing.

 

[Droidriven]

if I do this correctly the 'Lol, you did it again, look at your post.' will be missing.

You got it, you just needed to the first quote tab with my username and post to be at the beginning of my post, then my entire post after that and a quote tab on the end and my whole post would display.

You don't see a "quote" button or a "reply" button under everyone's posts? Are you using PC/mobile browser or a mobile app to view the forum?

Anyway, this is off topic, I'm just trying to help save the confusion of quoting everyone and everyone quoting you.

 

[tobyr65]

You don't see a "quote" button or a "reply" button under everyone's posts? Are you using PC/mobile browser or a mobile app to view the forum?

Anyway, this is off topic, I'm just trying to help save the confusion of quoting everyone and everyone quoting you.

I see them, I first used the reply but was told to use the info/help to do it right. That said to use the quote button which I do. But then I was deleting all but the quote part I wanted and leaving the bracketed, back slash QUOTE at the end. So to be clear I should leave in the beginning bracketed content and the end bracketed content?

 

[Droidriven]

I see them, I first used the reply but was told to use the info/help to do it right. That said to use the quote button which I do. But then I was deleting all but the quote part I wanted and leaving the bracketed, back slash QUOTE at the end. So to be clear I should leave in the beginning bracketed content and the end bracketed content?

Yes, leave the first quote bracket with the username, post number and member ID number inside the bracket, then the quoted post with a quote bracket on the end.

 

[tobyr65]

Yes, leave the first quote bracket with the username, post number and member ID number inside the bracket, then the quoted post with a quote bracket on the end.

And what is this reply do?

 

[Droidriven]

And what is this reply do?

Quote quotes, reply just replies

Now, back to topic

 

[newjerseyrunner]

We do know that our observable universe is spherical and the centre of it is somewhere between your eyeballs.

From whatever vantage point you are in at the time.

To be as exact as I can be: The observable universe is a sphere centered between the average location of all your sensors looking outwards from your position in time looking backwards.

 

[bapowell]

Everybody: the observable universe is not positively "spherical" in the sense of having positive curvature. The curvature of the observable universe is zero to within a percent, making it consistent with flatness. The universe *does* have spherical symmetry, on account of global isotropy.