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YT2095

Watching the Big Bang?

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so there`s no place anywhere the universe hasn`t moved into yet then, there`s a Brick wall at the end of it?

 

the universe isn`t Expanding?

 

only if the Above were True, could there be no point of origin.

 

That's not exactly true. You might say that every space-time point in the universe is the point of origin, as the Big Bang occurred here, there and everywhere. A crude analogy could be made to a rubber sheet with all points in a universe within a really dense circle. Now stretch the sheet in all directions and you see your universe expand. Of course, this analogy fails to account for two things--1) the extent of the observable universe is not infinite and 2) nevertheless, there is no prefered point in that finite region you can call a point of origin.

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Hmmm... Put that way it Does make a little more sense, Amazing the things you can do with a Rubber Sheet :)

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The simple way to think of it is that all the space that the universe incorporates came into existence in the bang, and that rather than expanding by adding new space, the universe has expanded because the space itself is expanding.

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I suppose it is possible if you were the void recording it in real-time, it would be impossible to get it on film because the speed of it happening would be so immense

 

That's not exactly true. You might say that every space-time point in the universe is the point of origin, as the Big Bang occurred here, there and everywhere. A crude analogy could be made to a rubber sheet with all points in a universe within a really dense circle. Now stretch the sheet in all directions and you see your universe expand. Of course, this analogy fails to account for two things--1) the extent of the observable universe is not infinite and 2) nevertheless, there is no prefered point in that finite region you can call a point of origin.

 

 

There are two theorys about the universe

 

1) That the universe since the big bang is constantly expanding called and ever-expanding universe

2) That the universe will one day reach the point where its momentum runs out and gravity will pull it back in again resulting in the big crunch

 

Personally i think the ever expanding universe theory is correct because i dont think that momentum has anything to do with it.

 

But thats my personal opinion.

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It would seem to me that "outward" would have to be measured from the center of the Big Bang. "Outward" in this instance is the particular direction going away from the "center" of the Big Bang.

 

There is no center, though.

 

there`s no Logical way something can be expanding in ALL directions at once without Some bits getting closer together, because that wouldn`t be expanding it would be getting Denser and that`s Contracting :)

 

btw, if any of our Physics staff thinks this should go into Speculations, feel free to move it. as long as I get answers that are Valid and Proven for my Questions, I`m happy :)

 

This is a common misperception of the big bang. Standard physics works for the explanations.

 

Non, and that happens to be my Entire point.

 

the balloon is expanding in One direction only, Outwards.

 

so the claim that you can look at Any part in Any direction and see the big bang is Bogus! unless there`s a Mirror out there to reflect those photons back in to your eyes.

it`s like trying to catch a ball you just threw by running in the other direction.

 

The dots would be continually emitting photons, or were doing so at the recombination, and that's what you see.

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Hmmm... Put that way it Does make a little more sense, Amazing the things you can do with a Rubber Sheet :)

 

I'm not big on the rubber sheet for other reasons, one of which Sayonara touches on. For one, it gives you this sense that space-time is material--I'm not a big fan of that view even if flows naturally from the math. Material space-time feeds into the notion that there is some ambient coordinate system that naturally applies to a varying topological space, which in turns gets us back to this whole "edge" and "center" business. So while GR could model a material called space-time, it's probably preferable simply to think of space-time as the topology's dimensionality and think of GR as a theory of fields within those dimensions.

 

That said, the thing to remember about expansion is its a affine-geometric theory. That is to say it means nothing without picking two random points and comparing their varying displacement from one another. Expansion also means that there is no particular point you can choose and say "this is origin;" any coordinate choice is arbitrary.

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I'm not big on the rubber sheet for other reasons, one of which Sayonara touches on. For one, it gives you this sense that space-time is material--I'm not a big fan of that view even if flows naturally from the math. Material space-time feeds into the notion that there is some ambient coordinate system that naturally applies to a varying topological space, which in turns gets us back to this whole "edge" and "center" business. So while GR could model a material called space-time, it's probably preferable simply to think of space-time as the topology's dimensionality and think of GR as a theory of fields within those dimensions.

 

That said, the thing to remember about expansion is its a affine-geometric theory. That is to say it means nothing without picking two random points and comparing their varying displacement from one another. Expansion also means that there is no particular point you can choose and say "this is origin;" any coordinate choice is arbitrary.

 

Is that what it called diffeomorphism by chance? What I don’t understand is for many other things in physical reality you can have an origin, yet not for this? Why is that? Is it simply a point of no origin based on the perception of origin in this case?

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Is that what it called diffeomorphism by chance?

 

Not sure what you're calling a diffeomorphism here. Are you referring to affine connections?

 

What I don’t understand is for many other things in physical reality you can have an origin, yet not for this? Why is that? Is it simply a point of no origin based on the perception of origin in this case?

 

Because many things in physical reality lend themselves readily to coordinization right off the bat. Spacetime, not so much. Part of this is because the math works so well without it, and you can always choose coordinates with a metric later.

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ok, well Thanks each, I have a General idea of how it works now :)

 

Cheerz!

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