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So the universe is like raisin bread. I just knew I tasted it from somewhere before but couldn't place it.

I feel that while worm holes and black holes are both cosmic singularities I don't think they have anything else in common, but I am not at all certain that there is a worm hole and think it may just be a plot device to a science fiction show because I have seen no hard evidence of the later. If worm holes are real thogh, I wonder if there is any connection to black holes and if so what?

I wonder if that article is the writings of a hypothesis or if this is is an actual theory because the author seems very sure about his answer, but I wonder how he can be if other scientists still discuss the possibilities of other universes outside our own.

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Hello Rallem,

I believe worm holes can be created. Maybe, they don't exist in nature without an external power source, and may I reinerate I am speaking from limited knowledge that may not be worth the time to read, but everyone has opinions. Again, I think the true nature or makeup of "space" is the defining factor in this discussion.

Like I said earlier, this is a very complicated subject. I had never heard it explained as the way this author explained it. I am assuming this is 1 theory on the table. As for "other universes", I was under the impression they exhisted but in another dimension completely void of our own. This is a relatively new subject and perhaps the "language" or words used in explaining are not making it clear.

You know, it could be that the universe needs no end, perhap it is irrelivant for an end. Something else to think about. I am sure one day the great minds will have an answer for all of us.

keep on thinking,
odin1


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Hello everyone,

Rallem said:

"But if this Univers has no end then how do we know it is expanding faster every day? Would the galaxies we see separating further apart every day be enough to to base a theory upon if the Universe were infinate as well as the posible galaxies we cannot see? If this Universe were not finite wouldn't a theory or hypothesis of an expanding Universe be sort of like a flat Earth Theory?"

Rallem, do you think the galaxies are moving away from each other or moving relative to each other? What I am getting at is this- if galaxy X is moving away from galaxy Y what causes the difference in speed? Assuming the same forces are acting on each galaxy? I understand there could be a difference in mass, but that shouldn't be a factor. Also, galaxies have collided, that has been talked about in another thread, and I would assume that if the speed is relative and they are moving from a central location this should not occur.

odin1




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odin1, re your question (above) to Rallem:

Your question suggests that you think the galaxies are moving away from each other 'through' space. That isn't the case. The Big Bang wasn't an explosion in the ordinary sense, in which material is ejected through space. When our universe originated as a point, that point was the whole of our spacetime continuum, the whole of our universe. Our universe was comprised of nothing other - no space 'outside' of it into which the energy could be radiated. Space itself stretched, and has continued to stretch.***

There are two relevant consequences of that:

(1) The Big Bang did not occur at one place to the exclusion of all other places. It occurred everywhere, because the point was 'everywhere'; so the concept of the 'central location', that you mentioned, is false.

(2) The relative motions of the galaxies result from the uniform - and currently accelerating - stretching of space, except to the extent that they are acted upon by mutual gravitational attraction. The expansion of space is carrying the galaxies with it. Hence the analogy of raisin bread rising in an oven.

*** There was (theoretically, of course), for a fraction of a second, a period of 'inflation'. There are many versions of the theory. Typically, you’ll be informed that during the period of inflation lasting 10-32 of a second, a volume of just a few cubic centimetres expanded to a volume roughly equal to that of the currently observable universe.

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Originally Posted By: odin1
Hello everyone,

Rallem said:

"But if this Univers has no end then how do we know it is expanding faster every day? Would the galaxies we see separating further apart every day be enough to to base a theory upon if the Universe were infinate as well as the posible galaxies we cannot see? If this Universe were not finite wouldn't a theory or hypothesis of an expanding Universe be sort of like a flat Earth Theory?"

Rallem, do you think the galaxies are moving away from each other or moving relative to each other? What I am getting at is this- if galaxy X is moving away from galaxy Y what causes the difference in speed? Assuming the same forces are acting on each galaxy? I understand there could be a difference in mass, but that shouldn't be a factor. Also, galaxies have collided, that has been talked about in another thread, and I would assume that if the speed is relative and they are moving from a central location this should not occur.

odin1




Yes, but my point is that if our Universe is boundless and infinite and that our telescopes can only detect galaxies from up to a certain distance of that infinite space then shouldn't we also assume that the number of galaxies inside the universe is almost infinite in itself and all those other possible galaxies we cannot detect might be doing something other than expanding away. Heck like you pointed out many of the galaxies we can detect aren't separating and I think one is about to collide with us in the next few billion years.

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Hello redewener,

My question is if the fabric of space is stretching then how does a galaxy collide with another. Assuming everything started from an epicenter what is the reason for the flunctuation in velocity of the galaxies-assuming of course the fabric of space is expanding and pulling the galaxies along like the raisin bread stretching. The raisins don't move, the dough moves, do you see my point? I am getting to something, I just want to see what you think.

best regards,
odin1


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odin1


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Odin I think you and I are asking a similar question and my problem is that I am not that articulate.

Last edited by Rallem; 05/05/08 08:07 PM.
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Hello Rallem,

You do real well, I should have read your question closer before I asked mine.

best regards,
odin1


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Originally Posted By: odin1
My question is if the fabric of space is stretching then how does a galaxy collide with another. Assuming everything started from an epicenter what is the reason for the flunctuation in velocity of the galaxies-assuming of course the fabric of space is expanding and pulling the galaxies along like the raisin bread stretching. The raisins don't move, the dough moves, do you see my point? I am getting to something, I just want to see what you think.

The galaxies are observed to be in groups, clusters, superclusters and supercluster complexes. On the largest scales, this gives the matter in the universe a foam-like structure. As space expands, this structure expands - but the gravity of galaxies that are comparatively close together counters the separating factor of the expansion, causing them either to separate at a slower rate, or be drawn together.

There was no epicentre, as there would have been if the Big Bang had been an explosion at some point in space. Expansion occurred everywhere at once. The Big Bang happened everywhere.
______________

Link to a page about the large scale structure of the universe http://www.mpa-garching.mpg.de/galform/millennium/

"The cold dark matter model has become the leading theoretical paradigm for the formation of structure in the Universe. Together with the theory of cosmic inflation, this model makes a clear prediction for the initial conditions for structure formation and predicts that structures grow hierarchically through gravitational instability."

And there's an absolutely brilliant movie:

"A 3-dimensional visualization of the Millennium Simulation. The movie shows a journey through the simulated universe. On the way, we visit a rich cluster of galaxies and fly around it. During the two minutes of the movie, we travel a distance for which light would need more than 2.4 billion years."

Beware - it's 120MB: http://www.mpa-garching.mpg.de/galform/data_vis/millennium_flythru.avi

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Hello rendewenur,

The question that is nagging at me is this. The galaxies don't move. It is the stretching of space that moves the galaxies, so the movement is relative to space. According to this article, the galaxies stay the same distance apart. If they stay the same distance apart (relative to the stretching of space)how can ones gravity capture another?

Let me put it like this, and I am using hypothetical numbers to make a point. If 5 billion years ago we had a big bang. The universe started stretching and moved along for another 2 billion years, in all that time "space" stretched and the galaxies stayed stationary relative to space. But, something happens, galaxy A gets captured by galaxy B's gravity. This overwhelms the forces that are expanding space and these two galaxies collide. What is present when they collide that wasn'nt present when the big bang occured 5 billion years ago?
Or why didn't it happen 1 billion years after the big bang?

You got me straight on the epicenter, I stand corrected.

Thanks,
odin1

Last edited by odin1; 05/06/08 12:31 AM.

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Ok, here I am about to make a total arse of myself by asking retarded questions after giving a little history to my reasoning. Shortly after the theory of the Big Bang was developed another theory called the Big Crunch was developed where it was predicted that gravity from the Universe would overtake the force of the expansion and the Universe would collapse in on itself. The Theory of the Big Crunch was later proven defunct though when it was determined that after several billions of years that not only is our Universe not expanding at slower rate, but it is growing faster every day. (Sorry for the possibly bad word choices) Now there is a theory that some day the Universe will be so big that the Galaxies and everything in them will be unable to hold themselves together and everything in the Universe will fall apart at the molecular level. Now back to the beginning, where shortly after the Big Bang pure energy had turned into matter somehow. We know this must have happened because of the vast amounts of matter which surrounds us. To the present, there are pictures from the Hubble Telescope showing a nursery for new born stars, so there must still be matter being made from the energy of the Universe, and here are my questions. How do we know that the Big Crunch is defunct? Can't this so called dark energy which is pushing our Universe ever so larger be converted into matter over time and be the actual source for our collapse in the future as it is the source for our expansion now? Couldn't the several billions of years our Universe has been around be anything but a blink in the eye beyond our scope and our Universe is still quite young and that is why we are expanding so quickly?

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Hello Rallem,

I think we should remember this is "theory" as you mentioned. But, we have to start somewhere. I have seen some articles debunking the big bang theory, so it is safe to assume that if there were no big bang, there will probably be no big crunch.

I really think, and this is my humble opinion, that we need to know what space is before we can measure it's "tensile strenght".
As of right now, we don't even know what gravity is. There are some theories, but no absolute proof.

And, you are not making an "arse" of yourself asking questions. If that were so, I would be on display in a state fair now.

Hopefully, redewenur will give some input to your question. He is pretty sharp at this.

best regards,
odin1



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Hi, odin1

I could quite easily have misunderstood your question, so bear with me if I have.

"The question that is nagging at me is this. The galaxies don't move. It is the stretching of space that moves the galaxies, so the movement is relative to space."

The movement isn't actually relative to space. The galaxies are stationary relative to space, unless acted upon by gravity of other galaxies.

"According to this article, the galaxies stay the same distance apart"

The article has misled you. The galaxies don't stay the same distance apart. The distance between them is increasing (unless they are acted upon by the gravity of other galaxies).

"If they stay the same distance apart (relative to the stretching of space) how can ones gravity capture another?"

The first galaxies are said to have formed more than 12 billion years ago. The youngest galaxy yet discovered, called I Zwicky 18, is thought to be less than 1 billion years old. As the galaxies condense at different times, there arise new gravitational sources. So, the galaxies have not been in a stable gravitational environment. It's been changing steadily over time, because of the gravitational instability. It's this gravitational instability that has caused the universe to have it's current, foamy large scale structure.

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Hello redewenur,

I see now that the space between the galaxies is stretching and they are getting further apart. I went back and read the article again. It is a good article, but like you said it can be a little misleading, and sometimes I have a tendency to speed read and miss a little something.

Do you thing that black holes may have anything to do with the collision of two galaxies?

P.S. I was reading a blog called "The Angry Astronmer" while ago about the big bang. It was pretty interesting, if you would like to read some of it I will send you a link.

thanks,
odin1


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Hi, Rallem.

"Ok, here I am about to make a total arse of myself by asking retarded questions"

Your questions are good. Not always easy to answer, but good.

"there are pictures from the Hubble Telescope showing a nursery for new born stars, so there must still be matter being made from the energy of the Universe"

Stars have there origins in two different ways.

(1) First generation stars. They are formed from the primordial matter that formed subatomic particles soon after the Big Bang, i.e., mainly hydrogen, some helium, and a little lithium.

(2) Second generation stars - or any generation after the first - are formed from the debris of supernovae (possibly with a little left over primordial gas, but I don't know about that). These are the stars that the Hubble telescope shows us.

So, no new matter is needed. It's old matter, recycled. Although there are new elements manufactured in stars, and then dispersed into space by supernovae. Hence the existence of our Earth.

"How do we know that the Big Crunch is defunct?"

We don't know for sure. It just looks a very unlikely scenario in view of the current accelerating expansion.

"Can't this so called dark energy which is pushing our Universe ever so larger be converted into matter over time and be the actual source for our collapse in the future as it is the source for our expansion now?"

Since no one yet knows what dark energy is, I would say that you could be right. There's just no evidence.

"Couldn't the several billions of years our Universe has been around be anything but a blink in the eye beyond our scope and our Universe is still quite young and that is why we are expanding so quickly?"

I don't see a possible connection between its age and its expansion rate, except for the period of inflation at the start, and the current observed acceleration. Do you?

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Hello everyone,

here is the blog site if you want to check it out.

best regards,
odin1
http://angryastronomer.blogspot.com/2006/07/big-bang-common-misconceptions.html


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Hi, odin1

"Do you think that black holes may have anything to do with the collision of two galaxies?"

I take it you're asking if I think they might be a cause of the collisions (as opposed to asking if they might be a result of the collisions).

Since the collision occurs as a result of mutual gravitational attraction between the total masses of the galaxies, whether or not that mass is partly within the black holes is unimportant.

Thanks for the link (angryastronomer). Jon Voisey has it right. Worth reading.

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Originally Posted By: odin1
Hello Rallem,

I think we should remember this is "theory" as you mentioned. But, we have to start somewhere. I have seen some articles debunking the big bang theory, so it is safe to assume that if there were no big bang, there will probably be no big crunch.

I really think, and this is my humble opinion, that we need to know what space is before we can measure it's "tensile strenght".
As of right now, we don't even know what gravity is. There are some theories, but no absolute proof.

And, you are not making an "arse" of yourself asking questions. If that were so, I would be on display in a state fair now.

Hopefully, redewenur will give some input to your question. He is pretty sharp at this.

best regards,
odin1



I would like to point out that this is not "just a theory," and while it is not a law of physics and it never can be one because of its complexity, as it mentions somewhere on this site in an article, a theory is not something to be taken lightly because a theory means that more than one Scientist subscribes to this theory and while parts of the theory can be altered when new information is provided it is difficult to debunk a whole theory.

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The accepted analogy for the expansion of the Universe, is the expansion of a balloon being blown up,
or better, the currants within a cake that is being baked.
The Galaxys, or currants separate from each other as the cake expands during baking.

While this analogy is true, my personal opinion is that our Universe may not be expanding consistantly in every direction.
Its shape might not be like an expanding rubber balloon, but more like a rubber glove complete with fingers.
The reason I think this is due to the large Galaxy Andromeda, that is fast approaching our own MilkyWay galaxy, and will eventually merge with us.
Just this single merging of two large galaxies, must spoil the accepted "nice even" spherical picture we believe the expanding Universe shows us. Plus there are a multitude more Galaxies out there that will eventually collide and merge, inspite of this constant expansion.
The Red shifts that we see now, will not change, but remember there are also a few blue shifts.
All in all this suggests to me that our Universe is not such an even expanding sphere as we might believe?
Protruding fingers of matter, even depressions, probably exist all around us?
Yet another question for Astronomers to prove or disprove?



.

.
"You will never find a real Human being - Even in a mirror." ....Mike Kremer.


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Mike: "Yet another question for Astronomers to prove or disprove?"

It's disproven already. The Cosmic Microwave Background Radiation has been observed to be isotropic. The irregularities of red/blue shift are accounted for by motion due to gravity that counters, adds to or subtracts from the rate of mutual recession.

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