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StarLab
2004-May-21, 03:54 PM
According to Oryx Frontier of Science Series: Recent Advances and Issues in Physics, in their glossary, the BB is defined as: the event that took place at the birth of the universe when energy was first converted into matter.
I just wanna makesure this is correct, especially the part about energy converting to matter...

Tiny
2004-May-21, 04:50 PM
Base on what I know, there are 2 explainations :
First one is the quantum-mechanical and second is the BB theory... For quantum-mechanical, particle attracted each other (+ and -) and later they create energy and matter (until today, I still don't know why).

For BB theory : There was nothing. Then, there was an explosion
which released a lot of energy. Eventually, the universe expanded and
cooled enough for some matter to form out.

Off topic again am I?

StarLab
2004-May-21, 05:41 PM
Off topic again am I?
Nope.

GOURDHEAD
2004-May-22, 02:31 PM
I just wanna makesure this is correct, especially the part about energy converting to matter...

Absolutely! It's in the Book! Several books. My guess is that if the BB really happened, at T = 0 + 10^-44 seconds The Higgs field was purely photonic, then quarks appear from pair formation, symmetry is broken and gravity appears as a separate force. The rest is history..sort of.

John L
2004-May-25, 04:01 PM
I think the grand unified force, the combination of gravity, the strong and weak nuclear, and the electromagnetic forces was responsible for inflation. When gravity separated from that unified force, then the inflation ceased and the rest is literally history.

geokker
2004-May-25, 10:55 PM
I think the Big Bang had to happen.

Imagine flipping a coin every second. It will land on heads, it will land on tails.

Given enough time, it will land on it's edge. It may take a million tosses, or maybe it'll happen in one. It is 'unlikely' to occur straight away, such is it's probability.

Give it some more time. It may turn into a banana or a colour TV. There is a probability for such unlikelyness.

So, probability occurs over time.

What would be the probability of 'everything' just happening? How many coin tosses? How long?

Imagine if there was 'no time'. Pehaps all probabilities would play out. Maybe the most improbable event - everything.

So, there was nothing, which could only turn into everything - explosively.

Pandora
2004-May-26, 12:57 AM
You would be correct if there is a beginning because of the probability 100% that the universe would happen since it did, but maybe a version of superstring (M) theory which poses that our universe is the result of a collision between 'branes' within an eternal pattern of motion. :o

national_acrobat
2004-May-27, 08:06 PM
if the big bang theory is true? then wouldn't it happen again and again?
imagine the universe expanding and over a period of time?? say a million light years?? all this begins to slow down?? then comes to a hault! than all would begin to collapse?? back into the very source that caused the big bang in the first place?

one question? where is the center? :huh:

StarLab
2004-May-27, 11:30 PM
Think of our universe as a balloon.
In the beginning, the balloon was deflated - and of a size so small it was infinitely airtight. Then, the balloon inflated in less than a second. In this scenario, the universe's center is the entire surface of the ballon, so that if you wanted to go from one end of the universe to the other, you'd eventually end up back where you started. It's like going all the way around earth to get from Honolulu to Honolulu, except you traverse the earth's entire circumference.
I hope that last part did not confuse you and was not too off topic

geokker
2004-May-28, 08:30 AM
In the beginning, the balloon was deflated - and of a size so small it was infinitely airtight.

StarLab, I think you are suggesting that the universe was 'infinitely' small at some stage of it's development. Do you mean the universe did not exist at one point in it's history?


so that if you wanted to go from one end of the universe to the other, you'd eventually end up back where you started.

So, If I started out in any direction trailing a tape measure, I'd be able to measure the universe? What would I be measuring? If I return to my point of departure, surely then the universe is faux-infinite, like a loop.

How can a system move from being infinite to finite?

I apologize for the number of questions here, but hey, it's a tough subject!

John L
2004-May-28, 03:57 PM
Originally posted by national_acrobat@May 27 2004, 03:06 PM
if the big bang theory is true? then wouldn't it happen again and again?
imagine the universe expanding and over a period of time?? say a million light years?? all this begins to slow down?? then comes to a hault! than all would begin to collapse?? back into the very source that caused the big bang in the first place?

one question? where is the center? :huh:
That's the Cyclic Universe scenario. The idea is that, yes, the universe begins to expand from an infinitely dense and hot point until it reaches a certain size and then gravity finally reigns it in and the entire thing collapses back in on itself in a Big Crunch!

There's also the Ekpyrotic Model, derived from string theory, that says our universe was created when two parallel 4branes in a 5D bulk space collided. The points of contact between the two 4branes released the energy that we have so far perceived as the Big Bang. This energy is then destined to spread out and thin out until the average energy per cubic lightyear is virtually zero, known as the Big Freeze. This process of 4brane collisions is also thought to be cyclical so that the two 4branes that originally collided will be drawn back together again and a new release of energy will occur fulling our universe, our 4brane, with more matter and energy that will spread and thin into another Big Freeze. Then rinse and repeat...

And there is no center.

StarLab
2004-May-28, 05:09 PM
So, If I started out in any direction trailing a tape measure, I'd be able to measure the universe? What would I be measuring? If I return to my point of departure, surely then the universe is faux-infinite, like a loop.

How can a system move from being infinite to finite?

I apologize for the number of questions here, but hey, it's a tough subject!
To go from infinite to finite or vice versa, I expect that two dimensions would either combine or separate. Hence, the four forces of nature...

I understand your confusion there. Use a thought experiment. It always helps. Imagine that on this balloon I described, the entire known universe was on its surface. Picture yourself going all the way around the universe and ending up right where you started from...you in effect, had you traveled in a relatively "straight" line, had traversed the circumference of the balloon universe.

It's like going all the way around earth to get from Honolulu to Honolulu, except you traverse the earth's entire circumference.


There's also the Ekpyrotic Model, derived from string theory, that says our universe was created when two parallel 4branes in a 5D bulk space collided. The points of contact between the two 4branes released the energy that we have so far perceived as the Big Bang. This energy is then destined to spread out and thin out until the average energy per cubic lightyear is virtually zero, known as the Big Freeze. This process of 4brane collisions is also thought to be cyclical so that the two 4branes that originally collided will be drawn back together again and a new release of energy will occur fulling our universe, our 4brane, with more matter and energy that will spread and thin into another Big Freeze. Then rinse and repeat... This is the model I believe. :)

Deep_Eye
2004-May-31, 08:39 PM
One problem though....where did the initial energy or matter come from? :P

StarLab
2004-May-31, 10:00 PM
According to the Ekpyrotic model, there were two universes that collided 13.7 billion years ago. One was a universe of matter, the other was a universe of energy. When they collided, the point at which they collided was known as the Big Bang. Then they started moving into each other and overlapping each other. As they overlapped, spacetime was created. Spacetime will continue to expand until both universes have finally overlapped each other completely.
In effect, the initial matter and energy came from these two universes that collided, which produced the matter and energy that we are all too familiar with today.

rahuldandekar
2004-Jun-01, 06:27 AM
How can a unioverse of matter exist without energy? Aren't they interconvertible? Does this intercovertiblity exist in our universe only? Why? What exists in other universes? What about antimatter? Was it or was it not there in the Matter universe? How were the initial matter and energy ( or something more basic than these) were created? Do only universes of matter and energy exist? What if two similar unievsres collide with each other?

Deep_Eye
2004-Jun-01, 12:53 PM
Really... neither energy nor matter can be created when EMPTY space collides with EMPTY space.

StarLab
2004-Jun-01, 04:09 PM
neither energy nor matter can be created when EMPTY space collides with EMPTY space.
That depends on what you mean by 'empty space.'

Rahuld, don't panic whatever you do...How the universes interacted within themselves before the Big Bang collision is none of our concern or worry.
But, when the two universes collided, they also combined. Our universe is a little bit of both and a mix of the two. :) :D

Deep_Eye
2004-Jun-01, 07:04 PM
By empty space I mean that there are no atoms in it-pefectly empty.

StarLab
2004-Jun-01, 07:28 PM
But there can be other stuff in it as well...
And as for Hydrogen atoms, there's plenty of that out in the universe, even intergalactical, but they are widely spaced out and separated.

Deep_Eye
2004-Jun-01, 08:09 PM
I mean the empty space outside of the galaxies. Like further out than any galaxy-there could still be empty space expanding in front of the galaxies-which would make sense.

StarLab
2004-Jun-01, 08:55 PM
That's what I said...intergalactic means 'between galaxies' :)

Deep_Eye
2004-Jun-01, 10:25 PM
Ermm. How can I explain what I meant....
Okay, imagine the expanding universe as a frisbe. Let the outer edge of the frisbee represent the furthest out galaxies. Now, imagine an imaginary ring (say a fourth of an inch or an inch-doesnt matter how much) that has nothing whatsoever in it. Its not inbetween galaxies at all-the galaxies are all on one side of it-which would be the side towards the center of the universe. Thats what I meant by the outer edge that is being pushed outward to mark the boundary of the universe, and closely behind it, the galaxies.

geokker
2004-Jun-02, 09:03 AM
I think the trick here is that the universe is getting bigger, but it isn't expanding into anything.

So, if the Universe were the surface of a sphere, two points would move apart as the sphere grew in 'volume'.

It is believed by some that because objects on average appear to be moving apart, the universe is growing in size - what we would perceive as an increase in volume.

So, if the universe were a frisby, there would be nothing beyond its edge, because there is no edge, there is just universe.

I find it very difficult to think of the universe as something other than an object.

Deep_Eye
2004-Jun-02, 12:32 PM
I believe the universe is spherical. I was just using the analogy with the frisbee to explain easier. I think the universe is expanding in 2 ways. First, the galaxies are rushing outward. And second, the space in between the galaxies and on the outer edge of the furthest galaxies, are expanding.

Sp1ke
2004-Jun-02, 01:30 PM
Even if you found a bit of space between galaxies and with not a single atom in it, it still wouldn't be empty. The structure of spacetime itself is in constant motion; the quantum foam. If you look close enough, there could be an infinite amount of energy in "empty" space.

StarLab
2004-Jun-02, 09:25 PM
Yeah! Spacetime itself is "stuff." And there is not one place where there isn't any stuff in the universe.

geokker
2004-Jun-03, 01:16 PM
I think the point is, there is no 'completely empty space' - there is only the universe. Just because distances between 'stuff' are lengthening, doesn't necessitate a 'beyond'.

Sp1ke
2004-Jun-03, 03:33 PM
If you did manage to find some 'completely empty space' with no stuff in it, how would you know it was there? :)

The space-time universe is all there is. There is no outside, just like there is no before and after.

StarLab
2004-Jun-03, 05:29 PM
There is an ouside, yet it has "different stuff."
I wonder...are there bubbles of "different stuff" in our universe?