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#3755 10/09/05 03:21 AM
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http://antwrp.gsfc.nasa.gov/apod/ap050925.html

After reading this and reading information in some of the connected links, I have a question. I don't expect anyone to be able to answer it, but i'll go ahead and ask anyway.

If the universe was created by the big bang, and is expanding, doesn't that imply that it has a size and shape? So then, does that not also imply that it has an edge? A border? What could lie beyond the edge of the universe? I'm guesing there are lots of things i'm not taking into account, so forgive me if this doesn't make any sense...


"The first Human who hurled an insult instead of a stone was the founder of civilization." -Sigmund Freud
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#3756 10/09/05 10:04 AM
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Well, it's probably like the computer game, Asteroids, where you go off one edge of the screen and appear on the opposite one.

In fact Asteroids was an early computer model of the universe, but most people missed the point and thought it was a game. smile

Blacknad

#3757 10/09/05 03:48 PM
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I like your analogy using the computer game but I see my monitor frame surrounding the screen. Seems like there's always something outside.
It's like we're in a self contained sphere of immeasurable expanse and we can't penetrate the confines of this habitat. If we launch a projectile out into the depths of our sphere the projectile will never reach the edge. It would seem in order to reach the outer boundary we would need more force than all the energy available to us so that would make it impossible to even know if there is an outside. We can speculate though.
What I mean by projectile is: a light beam, radio wave or any kind of particle. I also mean by this statement that any wave/beam/particle leaving the outer boundary of our sphere would not have enough energy to reach us therefore making information transfer from us to there and from there to us impossible. By not enough energy I mean, not enough energy to go faster than light.

#3758 10/09/05 10:47 PM
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Ric asks:
"If the universe was created by the big bang, and is expanding, doesn't that imply that it has a size and shape?"

The error in your question is in the assumption that any serious physicist believes the universe was created by the Big Bang: It wasn't.

Big Bang theory has nothing to say about anything that existed prior to the instant of the Big Bang. The Big Bang (with Inflation to be more accurate) theory only describes what has happened since.


DA Morgan
#3759 10/10/05 01:03 AM
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Quote:
If the universe was created by the big bang, and is expanding, doesn't that imply that it has a size and shape? So then, does that not also imply that it has an edge?
No. All 4(pi) steradians of direction at every location in the universe point exactly at the Big Bang. Every point in the universe is at its exact center. The universe is finite but unbounded. You can only see that part of it within your light cone.

The Big Bang was not an explosion in space, the Big Bang was an explosion of space. It made for an interesting geometry. Be glad that the resulting volume is orientable. OTOH, we could use more surface area/volume. My desk is a mess. Go hyperbolic!


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#3760 10/10/05 03:30 AM
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Da Morgan and Uncle Al:

What was there before the Big Bag and what was the source of the Mass for the Big Bang? Thanks.
jw

#3761 10/10/05 11:45 PM
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Jim,

I have never heard of the Big Bag theory and I certainly don't know what was there before it - maybe a Big Bong.

Regards,

Blacknad

#3762 10/11/05 01:38 PM
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JJW004,
I couldn't agree more.

Ric,
"What could lie beyond the edge of the universe?"
Possibly - more universes.

Blacknad,
Are you serious? You've never heard of the Big Bang theory?!

#3763 10/12/05 02:38 AM
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jjw004 wrote:
"What was there before the Big Bag and what was the source of the Mass for the Big Bang?"

I love how those that have nothing worthwhile to contribute make fun of an obvious typo. What a 'Christian' thing to do.

To answer your "what was there before" is an invalid question. First it assumes that there was SOME THING before: We don't know that that was true. Second it assumes that time existed prior to the event: We don't know that to be true either. We are completely ignorant of anything prior to a very small faction of a second after the event.

Keep in mind that the Big Bang with Inflation is described as an expansion of SPACE-TIME. Both time and space were created. Thus our anthropomorphic need for a before may just be a weakness of human imagination: Not physics.

Now to your question about mass. As we humans have mass and live in an environment in which things seem massive we care about mass a lot. But from a Quantum Mechanical point of view mass may just be, to use a very bad analogy, something like molasses. It causes things to resist acceleration.
It seems to be a consensus that it relates to interactions with Higg's Bosons (look it up with google). But I have increasing doubts given the inability to find any evidence of them yet.


DA Morgan
#3764 10/12/05 03:29 AM
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Naively there are reasons, from fundamental physics, to believe that the Universe should have produced about as much matter as antimatter. At the time of the "Big Bang" should there not have been equal amounts of matter and anti-matter? mad

Does every atomic particle have a polar opposite "anti" equivalent (eg. electron and antielectron); or does anti-matter only birth from energy being transformed into matter?

If so.. where is all of this anti-matter? There does not seem to be large collections of antimatter that we can detect. In PET scans, the positrons come from the decay of radioactive nuclei incorporated in a special fluid injected into the patient. The positrons then annihilate with electrons in nearby atoms. As the electron and positron are almost at rest when they annihilate, there is not enough annihilation energy to make even the lightest particle and antiparticle (the electron and the positron), so the energy emerges as two gamma-rays which shoot off in opposite directions to conserve momentum. Fine, so we can produce anti-matter in labs with PET scans and the Large Electron Positron (LEP) collider at CERN. But where is the rest of it from the "big bang"? Is the cosmic background radiation all that is leftover from the matter-antimatter annihilations...which, somehow, left only a billion to one ratio of matter to antimatter? Apologies if this sounds jumbled.
Sincerely,


"My God, it's full of stars!" -2010
#3765 10/12/05 10:47 AM
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Rob,

'Blacknad,
Are you serious? You've never heard of the Big Bang theory?! '

I was referring to the Big Bag theory - referring to a typo in gest.

DA Morgan,

I am sure I didn't hurt Jim's feelings - I am sure by what I have read from him that he would understand it was just gentle ribbing.

Regards,

Blacknad.

#3766 10/12/05 11:36 AM
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oh, now I see.

#3767 10/14/05 12:03 AM
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Mung asks about antimatter:

You are correct. Based on our understanding of symmetry there is every reason to believe there should have been as much matter as antimatter.

But based on B Factory work we also know that there are some asymmetries between matter and antimatter. They are not "just" mirror opposites.

Clearly we do not know why we don't see an equal amount of antimatter but keep in mind that baryonic matter is the smallest, percentage wise, constituent of the universe. Basically it, we, are about as meaningful as a carbon inclusion is to a diamond. It may well be that at one point in time there were essentially equal amounts. That they annihilated each other. And what is left is just the very small asymmetry from the original. We just do not know ... YET!


DA Morgan
#3768 10/17/05 03:04 PM
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is there such a thing as neutral matter?

#3769 10/18/05 04:53 PM
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Neutral in what sense? Electrical charge ... definitely. Color charge? Definitely not. Matter that won't annihilate? I can'think of a single example as even photons will annihilate other photons.


DA Morgan
#3770 10/18/05 11:09 PM
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I have no idea what is on the edge of the universe however surfaces of free floating fluids take the shape of a sphere when no forces act on it, I would say it?s a sphere but I really have no idea, as to what happened before it, I look to the universe expanding. . Will it stop? Will it teeter for a moment and reverse back to the centre. . In a sort of "Big Crunch" will it then explode as all the matter and energy collide like a giant particle accelerator this is pushing physics to its most mind boggling limits.
Back to the question what?s on the other side. . Is there even a theory or school of thought to challenge? It would be interesting to be on the great verge in a space ship only to pass through . . .

#3771 10/19/05 07:55 AM
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DA Morgan, what I meant was, if there's matter, and there's antimatter, shouldn't there be neutral matter?

#3772 10/19/05 11:34 AM
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Its hard to think of yet more grey in between the binaries of matter and anitmatter, what properties whould it have? can somthing exist of equal halves of a substance that destroys one another?

#3773 10/24/05 10:27 PM
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D.A. Morgan response to jjw, about 10//11

To answer your "what was there before" is an invalid question. First it assumes that there was SOME THING before: We don't know that that was true. Second it assumes that time existed prior to the event: We don't know that to be true either. We are completely ignorant of anything prior to a very small faction of a second after the event.

Keep in mind that the Big Bang with Inflation is described as an expansion of SPACE-TIME. Both time and space were created. Thus our anthropomorphic need for a before may just be a weakness of human imagination: Not physics.

Now to your question about mass. As we humans have mass and live in an environment in which things seem massive we care about mass a lot. But from a Quantum Mechanical point of view mass may just be, to use a very bad analogy, something like molasses. It causes things to resist acceleration.

Thank you DA. As to Rob, Please assume my feelings defy even intentional hurts.

When I read the above I see the shadow of a concept frequently offered by the religious. We know of nothing before, neither matter nor time and this Big Bag- err this Big Bang, came out of nowhere. Something of which we know not created space and time on the spot and then banged into an inflationary state of its own accord.

DA, this has all the earmarks of accepting some thing on faith because we admit we know nothing of what went before, if any thing and we know not what could have caused the ?event? to occur. When I look at the stars and consider the apparently endless quantity of stuff (forget Mass) that is out there I am personally compelled to wonder where it all came from. Inflation assumes compression existed prior to the inflation or you are compelled to use substitute creation as part of the inflation. If we can assume something in a state of compression then we have a pre-existence of stuff of which the Big Bang is constructed.

I do not intend a play on words. You offer that ?what was there before? is an invalid question? If invalid it is only because the theory is not capable of providing an answer.
From my standpoint a theory that does not provide a beginning should not presume to provide an ending. Why don?t we just believe there was a big bag of stuff there first?

I think I brought up Mass in another discussion so I will let that rest to conserve space.

With your skills you can understand why some of us may find the Big Bang theory hard to swallow. When the issue discusses the ?after? we think in terms of what was before.
When some one talks of inflation we think of compression unto inflation. When one of us thinks of expansion we automatically think that yesterday it was smaller. The Theory provides these descriptors, not the reader.
I always appreciate you insights and explanations and I continue to learn stuff.
jw

#3774 10/25/05 06:06 PM
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I missed a point.

I thought that it was basic physics that you can not make something of nothing? For your concept to fit we can think that while we do not know what was there before the Big Bang we just don't know what it was. Happy days.
jw

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