The Big Bang and our place within the timeline of the Universe. Is there a future that we can see?

We all know what the Big Bang Theory (BBT) states, right? That basically everything that came to exist, all matter, originated from one extremely dense point in the distance and exploded outwards with immense heat and force. Immediately after initial expansion the young Universe was very hot and dense, and with time things began to cool enough to allow for the formations of galaxies and stars, all the way down the scale...

Our current understanding is based on this:

As the distance between galaxy clusters is increasing today, it is inferred that everything was closer together in the past. This idea has been considered in detail back in time to extreme densities and temperatures,[13][14][15] and large particle accelerators have been built to experiment in such conditions, resulting in further development of the model

And it's usually accompanied by a diagram that looks like this:



This leads me to question many aspects of this theory and hoping that more intelligent folks than I could help me understand this more.

Are we making the right assumption about our place within the universe?

Our current estimates place the age of the universe at approximately 13.77 billion years, plus or minus a few... If we're to put that into the context of the diagram above then that would have to imply that we are on the very leading edge of the expansion looking in towards the point of the BB. That everything we see looking towards the big bang happened in the past.

So, since the BB happened at one point and everything expanded from it at the same (ever accelerating rate) then we might be able to assume the universe is spherical in shape with the BB being at the center of it all. Could we agree on this so far?

Ok great, so here come the questions:

This all has to assume then, that there's an implicit direction thru time and space that this expansion is happening, right? So if we are at the leading edge of this expansion then shouldn't we be able to look in the complete opposite direction of the BB to get a glimpse of what lies ahead? Or perhaps even outside our universe?

And if we're just inside the leading edge of the universe then wouldn't that have to mean it's older than we have estimated it be, since that would imply matter that has already formed before us?

More like the Big Bollocks Theory...

So what was in existence before the Universe?

Originally posted by PhotonEffect
So, since the BB happened at one point and everything expanded from it at the same (ever accelerating rate) then we might be able to assume the universe is spherical in shape with the BB being at the center of it all.
Could we agree on this so far?

No, we cant agree.
The universe didnt spread out from a point in the middle. It was the middle. It was and is everything.
It certainly could not be said to "happened at one point".
Like the expanding balloon analogy, the expansion doesnt come from any specific point. The "extra" space on an expanding balloon cannot be said to be coming from a particular place.
Now, just add a dimension for our universe.

Originally posted by PhotonEffect
This all has to assume then, that there's an implicit direction thru time and space that this expansion is happening, right? So if we are at the leading edge of this expansion then shouldn't we be able to look in the complete opposite direction of the BB to get a glimpse of what lies ahead? Or perhaps even outside our universe?

No. To all of it.

Originally posted by PhotonEffect
And if we're just inside the leading edge of the universe then wouldn't that have to mean it's older than we have estimated it be, since that would imply matter that has already formed before us?

Matter did form before us at this point in time. That is known.
Not sure what you're getting at here. The sun, for example, formed at a point in time long before I did.

reply to post by PhotonEffect


The Big Bang Never Happened

reply to post by PhotonEffect

Originally posted by PhotonEffect

Are we making the right assumption about our place within the universe?

If the answer to that question was known, it would no longer be an assumption.

Originally posted by PhotonEffect

[color=A7D698]The Big Bang and our place within the timeline of the Universe.

So, [color=A7D698]since the BB happened at one point and everything expanded from it at the same (ever accelerating rate) then we might be able to assume the universe is spherical in shape [color=A7D698]with the BB being at the center of it all. Could we agree on this so far?

This is just in general, and not necessarily directed at the OP. It is something that has been bugging me for awhile now, and seems to continue becoming more and more common.

More often than not, that phrase is used without the most important word: '[color=A7D698]Theory'.

To me, it just seems like many people nowadays, speak of it as if it is an undeniable fact, which is certainly is not.

I've been wondering how it's taught to kids in school. Are kids being taught that 'The Big Bang' did happen? Or are they being taught that it may have happened, but is just one possibility?

reply to post by PhotonEffect

So if we are at the leading edge of this expansion then shouldn't we be able to look in the complete opposite direction of the BB to get a glimpse of what lies ahead? Or perhaps even outside our universe?

What alfa1 says about the nature of the expansion is correct, but it doesn't really answer this question. Here's the correct answer – or rather, two of them, both correct. The first is that the minimum velocity of the 'leading edge of this expansion' in any direction must be at least the speed of light (obvious when you think about it). To see anything beyond the leading edge we'd need to shine a light on it, and the light can't travel any faster than the expansion of the universe itself, so you won't see nuth'n.

In fact the leading edge (if there is one – wait for Answer #2) would be moving faster than the speed of light, due to something called the metric expansion of space. So you'd be overtaking the light you shone out into the Great Beyond before it could hit anything and get back to you. Which also makes sense when you think about it, because photons are, after all, part of the universe.*

Now for the second answer. There is literally nothing – at least, in four-dimensional spacetime – outside the universe (you might be able to see how this is implied in the first answer). Nothing – not even empty space, not even a vacuum. Just a dimensionless Nothing. This can be hard for people to get their heads around.

Now here's something even harder. Quite a few theoretical physicists believe that the universe, though finite, is boundaryless. The best way to imagine this is to think, not just of looking beyond the universe, but of travelling beyond it. If you did this, you would never actually leave the universe (not even if you travelled faster than light) but would simply keep going till you found yourself in the place you started from.

And in fact, that's exactly what would happen to the light you shine outward to try to see beyond the universe. It travels on and on and on, always within the universe itself, and eventually one day it comes back and hits you from behind. Except that, by then, tens of billions of years will have passed, you wouldn't be there any more (or anywhere, really), and the light itself would have travelled so far, diffused so much and been redshifted so far down that it would have become part of the background radiation of the universe.

Which, of course, brings us right back to Answer #1.

*

Gosh, I must say I feel quite proud of that little effort. I suppose an actual physicist will be along to debunk me any minute now. We do have one or two on the site – or used to, at any rate.

*Actually, it wouldn't, because the expansion would eventually carry it beyond the observable universe, but let's not make things unnecessarily complicated.

Originally posted by alfa1

Originally posted by PhotonEffect
So, since the BB happened at one point and everything expanded from it at the same (ever accelerating rate) then we might be able to assume the universe is spherical in shape with the BB being at the center of it all.
Could we agree on this so far?

No, we cant agree.
The universe didnt spread out from a point in the middle. It was the middle. It was and is everything.
It certainly could not be said to "happened at one point".
Like the expanding balloon analogy, the expansion doesnt come from any specific point. The "extra" space on an expanding balloon cannot be said to be coming from a particular place.
Now, just add a dimension for our universe.

Ok then. The BBT says all matter originated from a point smaller than a pour on our skin. This is the prevailing theory, Im not making this up. And at the moment of the BB, everything suddenly expanded outwards, much like a balloon would. (as you so mentioned) In which direction is all of this matter going? Is it all one layer?

Originally posted by PhotonEffect
This all has to assume then, that there's an implicit direction thru time and space that this expansion is happening, right? So if we are at the leading edge of this expansion then shouldn't we be able to look in the complete opposite direction of the BB to get a glimpse of what lies ahead? Or perhaps even outside our universe?

No. To all of it.

Care to explain? Im asking questions here

Originally posted by PhotonEffect
And if we're just inside the leading edge of the universe then wouldn't that have to mean it's older than we have estimated it be, since that would imply matter that has already formed before us?

Matter did form before us at this point in time. That is known.
Not sure what you're getting at here. The sun, for example, formed at a point in time long before I did.

So if the fabric of space is a single layer of matter much like the surface of an expanding balloon then everything should be about the same age, yes? Or if not, then how thick, so to speak, is the current layer of matter from one side to the other? (like measuring the thickness of the surface of the balloon per se)

reply to post by Astyanax

Gosh, I must say I feel quite proud of that little effort.

As well you should that's the most insightful post I've read for quite a while

Originally posted by BrokenCircles
reply to post by PhotonEffect

 

Originally posted by PhotonEffect

Are we making the right assumption about our place within the universe?

If the answer to that question was known, it would no longer be an assumption.

Ain't that the truth. So you're saying our assumption is wrong then

Originally posted by PhotonEffect

[color=A7D698]The Big Bang and our place within the timeline of the Universe.

So, [color=A7D698]since the BB happened at one point and everything expanded from it at the same (ever accelerating rate) then we might be able to assume the universe is spherical in shape [color=A7D698]with the BB being at the center of it all. Could we agree on this so far?

This is just in general, and not necessarily directed at the OP. It is something that has been bugging me for awhile now, and seems to continue becoming more and more common.

More often than not, that phrase is used without the most important word: '[color=A7D698]Theory'.

To me, it just seems like many people nowadays, speak of it as if it is an undeniable fact, which is certainly is not.

I've been wondering how it's taught to kids in school. Are kids being taught that 'The Big Bang' did happen? Or are they being taught that it may have happened, but is just one possibility?

For the record and purpose of this thread we will "assume" that this is the correct theory. However in no way am I saying I buy into it. Consider this more of an exercise in poking holes in the balloon.

reply to post by Astyanax


Bravo for a fine effort. That was one solid crack at it! And just the sorts of mind boggling answers I was looking for.

To be quite honest I'll have to go back and reread the last couple of paragraphs to see if I can wrap my mind around what you wrote.

Expansion is occurring at the speed of light. But at an increasing rate?

And if we were to shine a light towards the edge, what would nothing look like I wonder? And what might the edge of the observable universe look like? But wait aren't we at the edge of it moving at the speed of light? This is where I lose myself....

Originally posted by PhotonEffect
Ok then. The BBT says all matter originated from a point smaller than a pour on our skin. This is the prevailing theory, Im not making this up. And at the moment of the BB, everything suddenly expanded outwards

No, again its a difference between the idea of matter exploding into space, and space itself exploding.
Things cant "expand outwards" from a point, because there is no "outwards" to expand into. It is in fact the "outwards" itself which is exploding, not the matter within.

For the rest of this discussion, forget matter altogether, just consider space itself. That is what gets bigger.

Originally posted by PhotonEffect
So if the fabric of space is a single layer of matter much like the surface of an expanding balloon then everything should be about the same age, yes? Or if not, then how thick, so to speak, is the current layer of matter from one side to the other? (like measuring the thickness of the surface of the balloon per se)

Every"thing" is the same age, yes.
Every proton you see, for example, is about the same age as all other protons.

The "thickness" of the current layer is the size of the universe. As fast as photons can travel in the time they have, together with the physical expansion that also occurred. After that, one could say the universe is "there", but with nothing in it. If nothing exists, is it "there" at all?

reply to post by Astyanax

Originally posted by Astyanax

Quite a few theoretical physicists believe that the universe, though finite, is boundaryless. The best way to imagine this is to think, not just of looking beyond the universe, but of travelling beyond it. If you did this, you would never actually leave the universe (not even if you travelled faster than light) [color=D4C785]but would simply keep going till you found yourself in the place you started from.

After eventually getting to that point, would you know that's where you were?

By the time you finally made it to that point where you had started, wouldn't it most likely be completely unrecognizable when compared to the way it was when you started?



[color=828282]I think that makes sense, but I'm not making any guarantees.



reply to post by PhotonEffect

Originally posted by PhotonEffect

.....So you're saying our assumption is wrong then

Not exactly. I basically just meant that it's neither wrong nor right, because it is something that we can neither prove nor disprove.

Originally posted by alfa1

Originally posted by PhotonEffect
Ok then. The BBT says all matter originated from a point smaller than a pour on our skin. This is the prevailing theory, Im not making this up. And at the moment of the BB, everything suddenly expanded outwards

No, again its a difference between the idea of matter exploding into space, and space itself exploding.
Things cant "expand outwards" from a point, because there is no "outwards" to expand into. It is in fact the "outwards" itself which is exploding, not the matter within.

For the rest of this discussion, forget matter altogether, just consider space itself. That is what gets bigger.

Ok, so Is "expanding" not the proper term to use here? If space is exploding then all matter that makes up space (including dark matter) is "spreading".... outwards into space I presume. There's no such thing as nothing in the confines of space (or our universe). Nothing then exists (or not) outside these boundaries... Ok...

So what happens to this idea of "nothing" when we discover theres's a multi-verse?

Originally posted by Astyanax
Gosh, I must say I feel quite proud of that little effort. I suppose an actual physicist will be along to debunk me any minute now. We do have one or two on the site – or used to, at any rate.

Great answer. Alfa1 was right of course but it was nice of you to elaborate with such a detailed answer.

Originally posted by PhotonEffect
So what happens to this idea of "nothing" when we discover theres's a multi-verse?

I guess we will cross that bridge when we get to it. I think it's possible to theorize a multi-verse, but I'm not convinced it's possible to discover such a thing. Anything you can observe would be in our universe. We also believe it's possible that part of our universe is outside the observable universe, so if we can't even see all of our own universe, how are we supposed to see, or "discover" any others? I hate to use the word "impossible" but I don't see how it's possible to discover other universes. That doesn't mean they don't exist, but it's speculative and perhaps it always will be.

Observable Universe

Assuming dark energy remains constant (an unchanging cosmological constant), so that the expansion rate of the universe continues to accelerate, there is a "future visibility limit" beyond which objects will never enter our observable universe at any time in the infinite future, because light emitted by objects outside that limit would never reach us. (A subtlety is that, because the Hubble parameter is decreasing with time, there can be cases where a galaxy that is receding from us just a bit faster than light does emit a signal that reaches us eventually[6][7]).

Originally posted by PhotonEffect
So if the fabric of space is a single layer of matter much like the surface of an expanding balloon then everything should be about the same age, yes? Or if not, then how thick, so to speak, is the current layer of matter from one side to the other? (like measuring the thickness of the surface of the balloon per se)

What if we viewed the BB Theory not as an explosion, but more like carbonation bubbles. You have these bubbles expanding, contracting, some pop and are reabsorbed, some pop and are lost as we see it, some merge together to form larger bubbles etc etc etc.

From our vantage point the foam looks like its all one piece, linked together, expanding and then contracting in the same manner. However, if we take a super close look we will find that is not necessarily the case.

By the time the foam settles down we are left with what we perceive as a full glass, with everything looking as if it were one piece. Is the liquid at the top older or younger than the liquid at the bottom? Is the liquid in the glass older or younger than the neighboring glass of liquid?

Drop something into the liquid though and you can start the process over... Pour that glass into another one and you can start the process over...

Theories are nice.... facts are essential...

In the middle is the awesome beauty of existence.

anyways.. just my 2 cents worth

ETA: Part of me wonders what existence would be like if the answers came easy? Why get out of bed?

Maybe this is one of those conundrums that life requires to operate and exist. The carrot at the end of the stick so to speak that forces evolution and forward momentum on all fronts.

Originally posted by Xcathdra


What if we viewed the BB Theory not as an explosion, but more like carbonation bubbles. You have these bubbles expanding, contracting, some pop and are reabsorbed, some pop and are lost as we see it, some merge together to form larger bubbles etc etc etc.

From our vantage point the foam looks like its all one piece, linked together, expanding and then contracting in the same manner. However, if we take a super close look we will find that is not necessarily the case.

By the time the foam settles down we are left with what we perceive as a full glass, with everything looking as if it were one piece. Is the liquid at the top older or younger than the liquid at the bottom? Is the liquid in the glass older or younger than the neighboring glass of liquid?

Drop something into the liquid though and you can start the process over... Pour that glass into another one and you can start the process over...

Theories are nice.... facts are essential...

In the middle is the awesome beauty of existence.

anyways.. just my 2 cents worth

Your post makes me thirsty for a tasty Guiness for some reason .....

What if the universe is just one giant pint of Guiness. Now that would be sweet

reply to post by PhotonEffect

Expansion is occurring at the speed of light. But at an increasing rate?

The rate varies, though it is always at least the speed of light. The slope of the outer envelope of the WMAP diagram you posted in the OP corresponds to the rate of expansion. Soon after the Big Bang there was a period of hyperinflation, but things settled down after that.

And if we were to shine a light towards the edge, what would nothing look like I wonder?

I already answered this. The light you shone – which is a stream of photons – could never overtake the 'leading edge', so it could never leave the universe. You can't see outside the universe, however hard you try.

Did you read Arbitrageur's post about the observable universe? I left that bit out earlier because it's even harder to visualise than the stuff I was talking about. Because of the expansion of space, the parts of the universe that are farthest from us – in both space and time – are invisible to us, because light from them hasn't had time to reach us since the Big Bang. We can't even see all of the universe we're in, let alone trying to see what's outside it.

By the way, I know it's an obvious point, but maybe we should all remind ourselves that the speed of light is not affected by the speed at which the object emitting it is travelling. You can't do Newtonian relative-velocity calculations with light. You can't, in other words, crank a starship up to nine-tenths of the speed of light, shine a light out of the front of it and expect that light to be travelling at 1.9c.