Big Bang - No Single point of Expansion

[Peter Watkins]

No it isn't. The increasing rate of galaxy separation is evidence of a slowing in the rate of expansion. Dark energy does not exist, nor does the need for it.

 

[Dmitry67]

ok, you're right, all astronomers in the world are wrong. I am listening to your Nobel-prize-winning theory :)

 

[Peter Watkins]

It is simplicity itself. As the universe expanded, density, and hence gravity, decreased faster in the outer regions. This shifted the centre of gravity inward which produced a disparity in expansion rates between inner and outer universe causing spreading. This produces the "faster with distance" view. Continued slowing increases the rate of separation. This should come as no surprise as it was always thought that gravity would slow expansion. And it is. The statement that increased separation is acceleration, is speculation. The same applies to the 1920's statement that the universe is expanding. What was observed is the fact that galaxies are moving apart at a rate that increases with distance. This could equally well be caused by collapse!

 

[Nebozilla]

How is there an outer universe or inner universe when there is no center to the universe? I don't understand what you mean that continued slowing accelerates seperation? Negative acceleration = positive acceleration?

No it isn't. The increasing rate of galaxy separation is evidence of a slowing in the rate of expansion. Dark energy does not exist, nor does the need for it.

Oh is this sarcasm? lol! Hopefully this is just a joke...

 

[Peter Watkins]

Why is it thought that there is no centre and no outer. That makes no sense and there can be no argument for it. The fact is that all observed phenomena can be explained by the four forces, and all large scale movement is the result of gravity acting upon matter. You should listen to what the universe is telling you. All the clues are there. For example, what sort of universe could you construct from the single observation that virtually all galaxies, in all directions, are exhibiting degrees of red-shift that increase with distance? Nothing else, and nobody elses interpretation.

 

[Nebozilla]

How CAN there be a center? The whole universe "exploded"...everywhere. The balloon or raisin bread analogy helps in understanding. If you make points all over the balloon and while its expanding, all points move away from each other the exact same amount so from any point it appears to be the center but that goes the same for the next point and so on. Its not normal so that's why its hard to grasp.

Well if i was Hubble when he first found the redshift and what it meant, it obviously means the universe is accelerating. The further out the "redder" they become.

 

[Peter Watkins]

The balloon analogy is pointless as it only describes the outer face of the universe. The raisin bread analogy is far more accurate in that it describes a three dimensional universe and demonstrates how the galaxies, (raisins), are moving apart. It also shows that as well as moving apart from each other, there is an overall movement in a single direction, that is, away from the baking tray, which represents the centre of the universe. The single loaf is, of course, only half a universe. The other half is beneath the tray.
The entire cosmological world accepts that the universe is expanding, ie., growing in volume, therefore, in times past it was smaller. The further back in time that we project, the smaller it was. There would have been a time when it was at it's smallest. Regardless of how small or large that was, that is the point from which it is expanding in all directions. This then is the region that could be said to be central. The outside edge needs no explaining.
Hubble did not discover the red-shift. Slipher did when studying distant nebulea. Hubble discovered that these are galaxies.

 

[Dmitry67]

Apparently, you don't understand the baloon analogy. Then here is another one.

Take an infinite line from -inf to inf
At a given time, t=1, put 'galaxies' at points marked with integer numbers.

Now, to look how that line looked at any time t, just multiple all distances by t.

For example, at t=1 galaxies are at -1,0,1,2,..
At t=10 they are at -10,0,10,20,
At t=0.001 they were at -0.001,0,0.001,0.002 etc

You can replace an infinite line with 2D or 3D surface

This analogy is not complete but it shows that:
1. There is no 'center' of expaction. The expansion looks the same from any point
2. If universe is infinite now, it was *ALWAYS* infinite, so BB is not a point.

 

[Dmitry67]

The entire cosmological world accepts that the universe is expanding, ie., growing in volume, therefore, in times past it was smaller
The further back in time that we project, the smaller it was. There would have been a time when it was at it's smallest. Regardless of how small or large that was, that is the point from which it is expanding in all directions. This then is the region that could be said to be central. The outside edge needs no explaining.
Hubble did not discover the red-shift. Slipher did when studying distant nebulea. Hubble discovered that these are galaxies.

This part is absolutely wrong.
The logic is very naive, like, "if I divide the infinity by sufficiently big number, I get 0" :)

Infinity multiplied by 0.000000000000000000000000000001 is not "smaller" then the original infinity

WHen we say that universe was "smaller" we always mean the "visible" universe, so, the finite part of it

 

[Chronos]

Peter, what other option is viable in the face of centuries of observational evidence? If the universe is not expanding, what is it doing? Einstein realized a static universe was not viable without ever looking through a telescope. I am not saying that is the last word on cosmology, but, it is incumbent on you to propose a viable alternative.

 

[Vanadium 50]

I am listening to your Nobel-prize-winning theory :)

Please don't encourage personal theories. As per PF-rules, they belong only in the IR section.

 

[Dmitry67]

It was a sarcasm.

 

[Peter Watkins]

Prior to 1912 and the discovery of red-shifted nebulea, the universe was thought to be fixed,immutable and perfect. The handiwork of God. We now know that it is, at best, a work in progress. Being thought perfect, it was stated by somebody who should have known better, that it would look the same no matter from where it was viewed. As this was in the nineteen teens, there could be no possible scientific basis for this statement. It was, at best, guesswork, and as such was foolhardy. I defy anybody to provide evidence that was known at that time, that could back up this claim.
With regard to expansion, I didn't say that the universe is not expanding, indeed the outer regions still are. What I said was that the "faster with distance" view could be produced by either an expanding or a collapsing universe, and that in 1929 they could not have known which it was. With the further information that we have today, they probably would have stated that collapse is more likely to be occurring than expansion.
With regard to the balloon analogy, this one dimensional surface is what the universe would resemble if escape velocity had been reached. There would, of course, be no clumps of matter, only the particles of the early, energy only universe.
So tell me, what is it that this forum has against the notion that gravity is exerting restraint from within that has caused the faster with distance view through slowing from within and that this produces the illusion of acceleration? It would seem entirely logical, obeys all physical laws and does not require the invention of a new force in order to explain things. We're not talking warp factors here, or time travel, merely interpreting information to produce the simpleist and easiest of answers.

 

[Nebozilla]

Oh Peter its not just this forum...Go to any astronomer and just ask what they believe is the current best theory behind the universe's future. Your assumption could be possible if there WAS a center but there isn't. Period. Also the balloon's surface is suppose to represent 3D. With the raisin bread, just imagine it suspending in nothing while expanding. No baking pan.

 

[Peter Watkins]

So why then does the einsteinonline website, which is heavily promoted by this forum, state categorically that the outward movement can be rewound to a single point? It also provides a pictorial representation which is essentially a "slice of pie" illustration whereby the universe is seen expanding from a single point. This type of picture is quite widely used and is to be praised for it's economical use of paper and ink. It is though, misleading. To understand fully what the universe is doing, simply fill in the rest of the pie and engage brain.

 

[Nebozilla]

So why then does the einsteinonline website, which is heavily promoted by this forum, state categorically that the outward movement can be rewound to a single point? It also provides a pictorial representation which is essentially a "slice of pie" illustration whereby the universe is seen expanding from a single point. This type of picture is quite widely used and is to be praised for it's economical use of paper and ink. It is though, misleading. To understand fully what the universe is doing, simply fill in the rest of the pie and engage brain.

Please do. I am done. I seriously thought this was a joke ...

 

[Peter Watkins]

So it's back to school for you then.

 

[Nebozilla]

Actually I am in school. I guess I will go back tomorrow then? Whats so hard to grasp about the Big Bang happening everywhere since there was no universe before it? Its hard to picture but it makes perfect sense. So maybe...

So it's back to school for you then.