The center of the Universe

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Fallingstar1971

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If the farther out you look, the farther back in time you see, then could it not be said that no matter what direction you look you are looking in the direction of the center of the Universe?

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origin

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No, you are simply looking farther back in time. If you could somehow look all the way back to the instant of the bigbang you would still not see the center of the universe you would just see the whole universe but it would be very small.
 
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darkmatter4brains

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I think the maps of the bakground microwave radiation might be an example of how you're not looking at the center of the Universe in all directions.

That map is from observing the background radiation (which is looking WAY back in time) in many directions. If the center of the Universe was viewed in all directions, the map should exhibit isotropy (i.e. invariant with respect to direction). But it does not. It does look different in different spots, as exhibited by the small scale structure that was detected - the supposed seeds of the galaxies.

EDIT: Although, since inflation happened well before the "let there be light" era of the Universe, which is the era when the microwave radiation came into being, I guess you could argue the Universe was already expanded to such an extent that the microwave radiation was not "far enough" back in time to preclude your idea above ....
 
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FlatEarth

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Fallingstar1971":1niattwv said:
If the farther out you look, the farther back in time you see, then could it not be said that no matter what direction you look you are looking in the direction of the center of the Universe?
I would say no. My opinion is that there is a geometric center to the universe, but it's because I believe the universe has certain properties. There are other concepts of the universe that may be more popular with cosmologists, but they seem fanciful and unsubstantiated to me. I like a simple universe. ;)

I think the universe expanded in all directions at the Big Bang, but probably not equally in all directions. Even so, I believe it's similar to a bubble in shape. I also believe the universe is finite in size even though it continues to expand at an accelerating rate. The Big Bang theory implies that it is finite because it says the universe started from a single point 13.7 billion years ago and grew from there. Because its age is finite and the rate of expansion is less than infinite, its size must also be finite. This doesn't mean the edge of the universe can be reached, because there could be a property of space-time that redirects matter and energy away from the extreme boundaries of the universe. To actually measure the universe, one would need to know where space-time is curving back.

With these properties, I think a center exists, and it occupies a certain point in the universe, perhaps moving depending on the overall shape and evolution of the universe.
 
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SpeedFreek

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The Big Bang does not actually imply that the universe is finite although a lot of people infer it - whether the universe is finite or infinite is an open question.

The Big Bang states that our observable part of the universe started off very small, but the universe as a whole might have been any size at that time. If the whole thing expands, then our observable part of it expands too. There is nothing to stop an infinite universe from expanding.
 
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FlatEarth

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SpeedFreek":16wht9xj said:
The Big Bang does not actually imply that the universe is finite although a lot of people infer it - whether the universe is finite or infinite is an open question.

The Big Bang states that our observable part of the universe started off very small, but the universe as a whole might have been any size at that time. If the whole thing expands, then our observable part of it expands too. There is nothing to stop an infinite universe from expanding.
We had this debate previously, and I concluded there are no absolute truths when it comes to this subject, but I do disagree with you about what can be deduced from the BB theory. The BB is a theory about our universe and not a theoretical multi-verse. There is no evidence that a MV exists! That's a String Theory concept, and only exists mathematically.

Before the BB, there was no space, time, or matter as we know it. So with the properties of the universe I believe to be correct, logic indicates a finite universe with a center. :) I always point out that this is my belief and not fact, but all other ideas on this subject are beliefs and not facts as well.
 
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Skibo1219

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So who is calculating the center ? Do they even have a theoretical center?
 
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MeteorWayne

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No, everywhere was the center and the edge at the same time. No point in the Universe is either, but every point is both, at the same time. When the Universe started out much smaller than an atom, everywhere is both.
 
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FlatEarth

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Skibo1219":2j439rif said:
So who is calculating the center ? Do they even have a theoretical center?
No one is calculating the center. It's not possible for us to do it, and pretty much all cosmologists don't believe it has a center. I do, but that's only my opinion, and I explain why in my earlier post. That's because I is pretty smart. :roll:

MeteorWayne":2j439rif said:
No, everywhere was the center and the edge at the same time. No point in the Universe is either, but every point is both, at the same time. When the Universe started out much smaller than an atom, everywhere is both.
Everywhere was the center and edge at the same time, but only before the Big Bang. A nanosecond after the BB this was no longer the case, and the universe had dimension...and a center.
 
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nimbus

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There's no center to an unbounded manifold. Wherever you go, there you are.
 
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SpeedFreek

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FlatEarth":2xhguwvd said:
We had this debate previously, and I concluded there are no absolute truths when it comes to this subject, but I do disagree with you about what can be deduced from the BB theory. The BB is a theory about our universe and not a theoretical multi-verse. There is no evidence that a MV exists! That's a String Theory concept, and only exists mathematically.
Who mentioned a multi-verse? I certainly did not. The BB is a theory about our universe, based on the parts of it we have received information from (i.e. the observable universe). Our universe is almost certainly larger than the parts we can see or have received information from, it might even be infinite in extent (which means it would have been infinite all along).

Our observable universe has a radius of around 46 billion light-years, but that limit is only a limit due to the time that light has had to travel. There may be galaxies in our universe that are currently further away than 46 billion light-years, but we cannot know of them.

But that doesn't stop them being part of the same universe that we are part of.
 
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Giulio

Guest
Ok, so let's assume that there is no multiverse. And Let's assume that the BB is correct and that space expanded from a micropoint to its present state. Can anyone tell me where this "cosmic microegg" was? What medium was it floating in? This is what I can never grasp about any theory that tries to explain the universe as a finite realm (e.g. The cosmic egg). No theory can ever explain to me what lies beyond. IMO, space must be infinite. No matter what any theory proposes, including the BB. If all of space was contained within a microspeck, then what was beyond it's bounderies? I can only assume that it was empty space. Whether the laws of physics in the "external" space is different is besides the point. That's why I don't believe in the BB nor any other theory I've ever examined. Our observations are somehow false or misleading. We just don't have all the facts. We are like a crab at the bottom of the ocean trying to imagine what the crab nebula might be by looking at it through 1000ft. of water, miles of atmosphere, LYs of space and all by using just our tiny brain.

So if I am correct and the universe is infinite, then there is no center.
 
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SpeedFreek

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Giulio":1ymxzioa said:
Ok, so let's assume that there is no multiverse. And Let's assume that the BB is correct and that space expanded from a micropoint to its present state.
The point I am trying to make here is that the BB theory only says that our observable universe expanded from a "micropoint". The universe itself could have already been any size at that time, and thus would have contained many separate "micropoints".

Giulio":1ymxzioa said:
Can anyone tell me where this "cosmic microegg" was? What medium was it floating in? This is what I can never grasp about any theory that tries to explain the universe as a finite realm (e.g. The cosmic egg). No theory can ever explain to me what lies beyond. IMO, space must be infinite. No matter what any theory proposes, including the BB. If all of space was contained within a microspeck, then what was beyond it's bounderies? I can only assume that it was empty space. Whether the laws of physics in the "external" space is different is besides the point. That's why I don't believe in the BB nor any other theory I've ever examined. Our observations are somehow false or misleading. We just don't have all the facts. We are like a crab at the bottom of the ocean trying to imagine what the crab nebula might be by looking at it through 1000ft. of water, miles of atmosphere, LYs of space and all by using just our tiny brain.

So if I am correct and the universe is infinite, then there is no center.
Have you considered that our universe might be embedded in a higher dimension? Or that it might be a manifold space which is finite but has no boundaries (i.e. the universe is multiply-connected and if it were possible to travel far enough one might find oneself back where one started)?
 
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neomaine

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Why do people still see the BB as coming from a single point? I'm by no means an expert but do understand that the fanciful idea of a big 'poof' from a single point is an overly simplified version for the general public to get the general idea, generally.

Maybe multiple single points appearing at multiple locations at the same 'time'? In other words, not so much a 'bang' = singulairity is exploding (though that is still true) but 'bang' = a bunch of things now exist.

If it was a 'bang' from a single singulairity, we would be able to see the paths of objects radiating out from what would eventually be a single point. That's not the case. We see multiple objects all (relatively) moving away from each other.
 
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FlatEarth

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SpeedFreek":2siqml6m said:
Who mentioned a multi-verse? I certainly did not. The BB is a theory about our universe, based on the parts of it we have received information from (i.e. the observable universe). Our universe is almost certainly larger than the parts we can see or have received information from, it might even be infinite in extent (which means it would have been infinite all along).

Our observable universe has a radius of around 46 billion light-years, but that limit is only a limit due to the time that light has had to travel. There may be galaxies in our universe that are currently further away than 46 billion light-years, but we cannot know of them.

But that doesn't stop them being part of the same universe that we are part of.
1) The Big Band Theory is about our universe in total and not about a portion of an even larger universe. Such a universe is not predicted by the BB. That's an adjunct to the theory and is really just speculation (Sorry, Michio Kaku.) That is why I thought you were talking about the only theory I know of that predicts a bigger universe: String Theory.
2) The universe is bigger than we can see, but that does not mean it is infinite. I just seems to be.
3) The BB theory does not say space existed before the BB, and the universe expanded into it. Matter, energy, time, and space resulted from the BB.

neomaine":2siqml6m said:
Why do people still see the BB as coming from a single point? I'm by no means an expert but do understand that the fanciful idea of a big 'poof' from a single point is an overly simplified version for the general public to get the general idea, generally.
Still believe? :? The BB is hardly fanciful, and it is not dumbed down so the average person can understand it. The BB is still the one and only theory supported by evidence that descibes the events that formed our universe.

neomaine":2siqml6m said:
If it was a 'bang' from a single singulairity, we would be able to see the paths of objects radiating out from what would eventually be a single point. That's not the case. We see multiple objects all (relatively) moving away from each other.
The Big Bang wasn't an explosion originating from a single point blowing matter into space. It was the violent expansion of space-time and matter-energy, and the expansion we see is the continuation of that event. Walk that process back in time and everything comes together (to a single point).
 
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MeteorWayne

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FlatEarth":2yb0uw22 said:
SpeedFreek":2yb0uw22 said:
1) The Big Band Theory is about our universe in total and not about a portion of an even larger universe.
Actually, the Big Band theory is about whether the brass over reeds is more tasteful than the reeds over brass theorum proposed by Glenn Miller.
 
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darkmatter4brains

Guest
SpeedFreek":15zzarz6 said:
Our observable universe has a radius of around 46 billion light-years, but that limit is only a limit due to the time that light has had to travel. There may be galaxies in our universe that are currently further away than 46 billion light-years, but we cannot know of them.
Is that how observable universe is defined these days? Seems a bit of a stretch to me, although I guess it's reasonable.

From what I understand, each galaxy has what we commonly refer to as distance, but it also has a comoving distance. Comoving distance accounts for the fact that the galaxy has been racing away from us with the expansion of space since the light we observe has left it. In other words for a galaxy that is 13 billion light years away ... well, that light left it 13 billion years ago, but it's been expanding away from us for that whole time, so it's really further away now. The further away the galaxy, the larger the difference between the "light distance" and the comoving distance, since the further away objects are the faster they seem to be receding away from us.

Anyhow, when they say a galaxy is 15 billion light years away as observed through a telescope, it's really something like the 46 billion light years away away now, like you mentioned.

So, I wouldn't say we really looked that far out, because we can only see out as far as light has had time to travel to us, which is roughly the age of the Universe.

At least I think that's how it works? Maybe that's what you meant anyhow.
 
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SpeedFreek

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FlatEarth":ixhr4ffm said:
1) The Big Band Theory is about our universe in total and not about a portion of an even larger universe. Such a universe is not predicted by the BB. That's an adjunct to the theory and is really just speculation (Sorry, Michio Kaku.) That is why I thought you were talking about the only theory I know of that predicts a bigger universe: String Theory.
Sorry, but I think we are talking across each other here, referring to different concepts. I am not referring to any kind of universe that is not our own. All I am referring to are the parts of the universe we have never received a photon from.

No evidence exists to suggest that the boundary of the observable universe represents the size of the physical universe. If the physical universe has a boundary (which most doubt), and that boundary was at the edge of our observable universe, it would imply that the Earth is actually at the centre of the universe, in violation of the cosmological principle.

Consider the CMBR. These CMBR photons were released throughout the universe, around 400,000 years after the Big Bang. We detect them today, and as all photons travel at c, we assume the CMBR photons we currently detect in all directions were originally emitted at the same distance in all directions. Their emission points form a conceptual sphere around us, known as the particle horizon.

The Big Bang theory states that the CMBR photons we currently detect were originally emitted only around 40 million light-years away, and the place that they were emitted from has receded with the expansion of the universe to a current distance of around 46 billion light years away. This is what represents the edge of our observable universe.

We assume that CMBR photons were released around here too, and those photons would now be 46 billion light-years away. So, just as there are galaxies around here but 13.7 billion years ago CMBR photons were emitted here, we assume there now are galaxies 46 billion light-years away in the region of the universe where the CMBR photons we detect were originally emitted from.

Now then, as the CMBR was released throughout the universe, we can assume that CMBR photons have been hitting the Earth throughout history. We can also assume that we will continue to detect CMBR photons in the future, photons that were originally emitted further away than the CMBR we currently detect.

So, unless we suddenly stop detecting the CMBR, we can assume that there are now galaxies further away than 46 billion light-years. Only if we suddenly stop detecting the CMBR, we will know the universe is finite and that we have detected photons from every part. Until then, we can assume we will keep on detecting the CMBR, which means the universe is currently larger than our observable part of it.

Cosmic Inflation (which is part of the mainstream Big Bang model) estimates the size of the physical universe to be at least 10^23 times the size of the observable universe.

This is all mainstream Lambda-CDM cosmology, nothing to do with string theory or the parallel universes that Kaku posits.
 
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FlatEarth

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MeteorWayne":33bvp5x9 said:
FlatEarth":33bvp5x9 said:
SpeedFreek":33bvp5x9 said:
1) The Big Band Theory is about our universe in total and not about a portion of an even larger universe.
Actually, the Big Band theory is about whether the brass over reeds is more tasteful than the reeds over brass theorum proposed by Glenn Miller.
:lol:
Yes, I am prone to miscues of the fingers. I also occasionally spell my name FatEarth... :roll:
 
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FlatEarth

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nimbus":1tbsvnd7 said:
There's no center to an unbounded manifold. Wherever you go, there you are.
I believe this is the most accepted configuration of the universe, and if it is so, then there is no center.
 
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kangroo111

Guest
the center of the universe will be the earth, as i believe.
 
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origin

Guest
kangroo111":21cey707 said:
the center of the universe will be the earth, as i believe.
Actually, it only seems that way. My teenage daughter has made it very clear that she is the center of the universe and apparently the earth just has the lucky coincidence of being her home. :D
 
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SpeedFreek

Guest
FlatEarth":3ny58bnj said:
Well stated, and you certainly prove that you know this material better than most. The post where you state "The Big Bang states that our observable part of the universe started off very small, but the universe as a whole might have been any size at that time." is the one I argue against. The "universe as a whole" implies a greater universe than the one produced by the BB.
No, it implies that we can only see a small part of the universe that was "produced" by the BB.
 
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Compaq38

Guest
Infinity is the center of the Universe. So Infinity being (A) It is as big as A to the first power. A x 1=1A. So to answer your question the Universe is 1A in size. Since one can be of any size. 1A remands the same.
 
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