Picture of galaxy from when expansion only 600 million years old

[michel123456]

The CMBR does not grow.

O.K.

 

The red rings in the drawings are not actual objects, but the view from Earth.

O.K.

Think of it as an event, that occurred simultaneously throughout the universe.

O.K.

As you move farther into the future from that event, you will have to look a farther distance in order to see it, because the light emitted from the nearby parts of it will have already passed.

 

Yes. And what we see is the actual event. We are looking at the large CMBR (on your last diagram, the one on the right), and you must label it "young universe". The "young " is not the left diagram.

 

I'll try to explain my point otherwise:

 

1.In Euclidian geometry, there is a relation between inside and outside. Outside is bigger than inside. Take 2 concentric circles (the one inside the other). The outside circle is bigger than the inside circle(looks like tautology).

2.What I say is that the CMBR circle is outside us. Thus, CMBR circle is bigger than us (and not smaller than us).

3. What I say is that CMBR is not an old circle. What I say is that CMBR is a young circle.*

4.The only way to make statement1.false, is to turn Euclidian geometry inside-out.

 

But IMHO it is a nonsense to turn Euclidian geometry inside-out for the sake of an observation based itself on Euclidian geometry: expansion.

 

If you disagree with points 1 & 2 , I don't know what else to say...

 

*after reading my own post, maybe this point needs an explanation. When we say "the age of the Universe is 13,7 billions years", it means that "our present time is 13,7 billions years old". In other words, 13,7 billions years is our age comparative to the time of the BB. What we are observing is not 13,7 billions years old. As much we look far away, as much we look in the past. What we see in the CMBR is not the picture of an old man. What we see is the picture of a young man. That's the reason why UDFy-38135539 is considered a young galaxy.

[Sisyphus]

Nobody is turning Euclidean geometry inside out. You're making this a lot more complicated than it is.

 

Let's ignore expansion for a moment. Suppose over time, every object maintains a constant distance. Suppose the universe is opaque, and then it becomes transparent. At first, an observer won't be able to see anything despite the transparency, because light hasn't had time to travel from other objects. Soon, nearby objects appear, and then farther and farther away objects, as their light has time to reach the observer. As time progresses, the observer will be able to see more and more of the universe, in a region of an expanding sphere.

 

Ok so far?

[michel123456]

Nobody is turning Euclidean geometry inside out. You're making this a lot more complicated than it is.

 

Let's ignore expansion for a moment. Suppose over time, every object maintains a constant distance. Suppose the universe is opaque, and then it becomes transparent. At first, an observer won't be able to see anything despite the transparency, because light hasn't had time to travel from other objects. Soon, nearby objects appear, and then farther and farther away objects, as their light has time to reach the observer. As time progresses, the observer will be able to see more and more of the universe, in a region of an expanding sphere.

 

Ok so far?

 

You are describing as if the observer was in a dark room and opened his eyes. As if the room existed before its discovery. In other words, stars & galaxies have been there where there are, and we are discovering a universe that preexisted but was opaque. If that is the Big Bang Theory, then i have to fight more.

 

So, No. I understand your point and under your assumption, your description is correct, but it's not o.k. so far.

 

BTW, in this case, you must agree with sketch A. (I guess, because for expansion, the inside circle is the newer, and the outside circle is the older)

 

And also, you description states that our cosmic horizon grows over time. I don't know if we have any evidence supporting this.

Edited November 1, 2010 by michel123456

[Sisyphus]

In other words, stars & galaxies have been there where there are, and we are discovering a universe that preexisted but was opaque.

 

Yes, exactly. The early universe was too hot for atoms to form, and was densely filled with free electrons that prohibited photons from traveling very far before being scattered. It "scrambled the picture." It was effectively opaque. As it expanded, it cooled, and when it cooled enough, atoms formed and it became transparent, at which point the universe would be gradually revealed to an observer.

 

That it continues to expand complicates this picture, but does not change that basic description.

[michel123456]

Yes, exactly. The early universe was too hot for atoms to form, and was densely filled with free electrons that prohibited photons from traveling very far before being scattered. It "scrambled the picture." It was effectively opaque. As it expanded, it cooled, and when it cooled enough, atoms formed and it became transparent, at which point the universe would be gradually revealed to an observer.

 

That it continues to expand complicates this picture, but does not change that basic description.

 

Doesn't that sound "ad hoc" to you? You are undoubtedly a smart person.

 

So: if I understand your point, stars & galaxies were created approximatively in place & state of motion as they are observed today.

The observable Universe of Ancient Mesopotamians is smaller than ours.

And our observable Universe is growing of one LY a year, probably more due to expansion. (I never heard of anything like that).

 

And why is UDFy-38135539 called a "young galaxy"? (edit.O.k. this one i can figure out.

If your point is part of the standard explanation of the BB, then the BBT is more monstruous than I ever thought of.

Edited November 1, 2010 by michel123456

[imatfaal]

397,000 years after the big bang the universe was still hot enough to be opaque (leonard susskind likens it to trying to look through the sun) . It was like this everywhere!

 

As the electrons and nuclei combined to form neutral atoms the universe became transparent (the final stages of this is lyrically known as the epoch of last scattering) and the last vestiges of this burning bright universe was not scattered. There was a relatively brief period in which radiation was produced - but was not scattered. This radiation was very energetic and radiated by every point of the universe and in every direction. The area which will later contain sol and earth produced this radiation as well.

 

This radiation has continued to travel as the universe has expanded. The radiation that was given off by the area which will later contain sol and earth has been travelling for 13.ish billion years away from us. the radiation we can currently detect has been travelling for 13.ish billion years towards us. 1 billion years ago - an observer near sol would have seen the radiation that had travelled for 12ish billion years, it would have been less red-shifted and coming from a nearer point of the universe.

 

Because the universe has expanded during those 13ish bilion years the initially very energetic radiation has been red-shifted all the way down to the microwave .

 

We are obviously at the centre of a sphere of observance - because our observables define that sphere. But that sphere is repeated for every observation point in the universe. the sphere of observance is not some form of real result/wavefront/artifact from the big bang; it is merely that the light from 13ish billion years ago from every direction reaches us at the same time (ie now) .

 

the big bang happened everywhere - and thus its effects are visible everywhere; we see them in a sphere because we need to look back 13 billion years - and that creates a spherical observation

 

I now see Sisyphus has already done this - oh well never mind

[michel123456]

Nobody is turning Euclidean geometry inside out. You're making this a lot more complicated than it is.

 

Let's ignore expansion for a moment. Suppose over time, every object maintains a constant distance. Suppose the universe is opaque, and then it becomes transparent. At first, an observer won't be able to see anything despite the transparency, because light hasn't had time to travel from other objects. Soon, nearby objects appear, and then farther and farther away objects, as their light has time to reach the observer. As time progresses, the observer will be able to see more and more of the universe, in a region of an expanding sphere.

 

Ok so far?

 

after a while, i just realize you are explaining the BBT without expansion. Which is resumed in "stars & galaxies have been there where there are, and we are discovering a universe that preexisted but was opaque."

 

Horror.

I guess you will answer that our horizon cannot increase because we have reached the "blindness point".

Horror squared.

 

also, what you are saying is that the Observable Universe is roughly the same, independently of the place in space, but not the same in function of time. An Alien living upon a planet 13 billion years ago ( somewhere in UDFy-38135539) was observing a different Universe.

Horror.

Edited November 1, 2010 by michel123456

[Spyman]

I completely disagree with you. The movie do not show the Universe TODAY. It shows the universe that we are observing today from the Earth, as it was some time ago. The "time-ago" feature expands in the past as much we go far away in distance. When we reach the limits of our observable universe, at time 3,36 in the movie, we are closer to the Big Bang than we are today. It is a travel in the past, not only a travel in space.

Actually we don't "completely" disagree, the movie doesn't show the Universe as how it is now, it shows how it appear to us now and since distant parts are far away those images comes from a remote past, this we agree on.

 

But we are not moving through time when we look at more distant parts, we see them as they where a long time ago and not how the Universe should look as compared to if we actually should make a simulation where time was in reverse.

 

We observe these distant objects as they where when the Universe was young, thus the image is arriving from a time closer to the Big Bang but neither the distant object at the time of the image or we on Earth today are physically any closer or more distant to the Big Bang, in terms of distance in space.

 

In a single question, which is bigger, the Earth, or the entire Universe?

I don't understand your question, of course the Universe is bigger than Earth. The bubble surrounding Earth in the movie at 3:36 is the Cosmic Microwave Backgroud Radiation, which is emitted from a shell surrounding this place that later became our solarsystem. Our cosmic horizon has always been bigger than our location.

 

And here I understand that I cannot make myself clear. What you don't understand is exactly the same as my objection upon the BBT. I am claiming that observation is that the rings grow when we go back in time, and that the analogy of the rock throwned into a lake is exactly the contrary of observation.

No, we are NOT observing that space are growing when we go back in time, we are unable to make such observations since we can't travel backwards in time and measure space. What we can observe is different layers of distance from different ages and according to their redshifts their distances seems to inrease.

 

The Big Bang theory does not claim that if we look up towards a galaxy like UDFy-38135539, from which the light took 13.1 billion years to reach us, that it was 13.1 billion lightyears distant 13.1 billion years ago. According to Big Bang theory it was more like ~3 billion lightyears distant when the light was emitted and is now ~30 billions lightyears distant.

(Cosmo calculator Omega=0.27 Lambda=0.73 Hubble=71 Redshift=8.55)

 

In a more distant view we are seeing objects as they were in a more remote past but not how far away they where when the light we see were emitted from them.

 

1) We can not first look up from the North pole at light 10 billion years old from a galaxy and then look down from the South pole at light 10 billion years old from a galaxy, to finally conclude that they where 20 billion lightyears apart 10 billion years ago. We don't know how distant they are now or how distant they were back then when the light was emitted.

2) And we can not compare galaxies with light 5 billion years old with galaxies that has 10 billion years old light and conclude that because the older light has traveled further the remote Universe must have been larger. All we know is that the older light was emitted from a larger distance than the younger light.

3) What we can do is measure their redshift and conclude that they are receding from us and as such they should have been closer in the past and likely are more distant today. From several measurements of different redshifts from different distances we can then build a model of how the Universe develops over time.

 

 

----------

 

So if we are observing light that is 14bn years old it must have been at least 14bn LY away when it was emitted???

No, if the geometry of space was rigid and fixed then you would be correct, but we have discovered that the geometry of space is highly dynamic and able to both expand and contract.

 

----------

 

 

I guess you will answer that our horizon cannot increase because we have reached the "blindness point".

The sphere of our observable universe is growing every year but the recent discovered acceleration of expansion will eventually bring very distant stuff outside of it, making us see less and less even though we continue to view an increasing volume, since it will be emptier.

 

also, what you are saying is that the Observable Universe is roughly the same, independently of the place in space, but not the same in function of time. An Alien living upon a planet 13 billion years ago ( somewhere in UDFy-38135539) was observing a different Universe.

Yes, an alien today, on a planet that is 13 billion lightyears away in proper distance, will view a different but similar Universe of the same age and an alien 13 billion years ago, on a planet close to the place Earth exists in today, would be able to view a much younger part of the Universe than what we are currently viewing.

Edited November 1, 2010 by Spyman

[michel123456]

Sysiphus is clearer than Spyman.

I don't swallow anything of his explanations, but at least he was clear. I have read tons of books (well, maybe exagerating a bit) about the BB, it is the first time I realize the Theory stands without expansion. Sorry for the ridicule, I thought expansion was the alpha-omega. I have never read that everything was created in place. It looks such an insanity to me that I have some difficulty to understand how this theory has been admitted by the scientific community but anyway. The phrase "the Big Bang happened everywhere" is also something that looks like word-salad, but anyway again, nobody can fight that with philosophical concepts.

 

So.

Universe were created roughly in place we see it today. One day, 13,7 billion years ago, "lux fuit". Behind the curtain, where no observations are available, laws of physics can change. Superluminal speed is common sense, and negative gravity is the law. There is no way to fight that. If laws of physics change when there is complete lack of evidence, there is no rule of the game anymore.

 

What else?

Spyman wrote:

 

We observe these distant objects as they where when the Universe was young, thus the image is arriving from a time closer to the Big Bang but neither the distant object at the time of the image or we on Earth today are physically any closer or more distant to the Big Bang, in terms of distance in space.

That is much confusing. All diagrams I know concerning the BBT have 2 axis, Space & Time. And there is a very accurate relationship between space & time. Space expands with time, and objects get closer to each other as much we go back in time.

Like this one (from wiki)

 

Or this one (the image is too large to load)

Where the hell is Sysiphus explanation?

 

Or this one

Spyman wrote:

1) We can not first look up from the North pole at light 10 billion years old from a galaxy and then look down from the South pole at light 10 billion years old from a galaxy, to finally conclude that they where 20 billion lightyears apart 10 billion years ago. We don't know how distant they are now or .

I agree that we don't know how distant they are now, but I don't understand why we don't know how distant they were back then when the light was emitted. To me, if they are in opposite directions, at the same distance, we must be able to calculate their mutual distance at the time light was emitted. And anyway what imports to this discussion is that those 2 galaxies, because they are at the same distance from us, are simultanate events.

 

 

Actually we don't "completely" disagree, the movie doesn't show the Universe as how it is now, it shows how it appear to us now and since distant parts are far away those images comes from a remote past, this we agree on.

 

But we are not moving through time when we look at more distant parts, we see them as they where a long time ago and not how the Universe should look as compared to if we actually should make a simulation where time was in reverse.

 

 

How can, we don't disagree at all! I never said it was a simulation of reversal time. If i did, sorry, not my intention. What i meant is that Universe was huuuuuuuuuge a long time ago, and that I cannot conceive it came out of a singularity. From the moment Sysiphus presents BB like an already-in-place-creation, it cancels everything, logic included.

 

And finally:

The sphere of our observable universe is growing every year

Do you have any evidence to provide? Edited November 1, 2010 by michel123456

[michel123456]

And how is it possible that the 'curtain" opened everywhere at the same time? If it is part of the horizon problem, it is not addressed in the wiki article.

[Spyman]

Sysiphus is clearer than Spyman.

Sorry to be unclear, I tried to focus on your statement that the Universe seems to be bigger in the past, of which you still don't seem to understand why it is wrong. I don't know how to explain it to you any better than what I already has done.

 

Maybe instead you could try to explain why an more distant image from an earlier time would conclude that the image must have arrived from a larger place?

(Or at least from a distant further away than where it seems to be from today.)

 

 

I have never read that everything was created in place.

There are two different Big Bangs, the first is about the Bang event itself, how the Universe came into being and the second is about the evolution of the Universe after it's "birth" from this small and hot state, which is the theory of the Big Bang.

 

We don't know how the Universe was created, there are several highly speculative and different competing ideas of that part. What we can model and test however is that if we go back in time roughly 13.7 billion years then the Universe was much more dense and hotter than today.

 

"A tale of two big bangs

Whenever you hear or read about cosmology, there is one distinction you should have in the back of your mind - otherwise, matters might get a bit confusing: The term "big bang" has two slightly different meanings, and the answer to questions like "Did the big bang really happen" depends crucially on which of the two big bangs you are talking about.

 

Did the big bang really happen? If you are talking about the big bang phase, the hot early universe as described by well-known physical theories (or, if you include inflation, by extrapolation from those theories), then there is good evidence that, yes, nearly 14 billion years ago, the cosmos developed in just the way described by the cosmological models (the main exhibits are the original abundances of light elements as deduced from astronomical observation, the distribution of far-away galaxies and the existence and properties of the so-called cosmic background radiation).

 

Whether or not there really was a big bang singularity is a totally different question. Most cosmologists would be very surprised if it turned out that our universe really did have an infinitely dense, infinitely hot, infinitely curved beginning. Commonly, the fact that a model predicts infinite values for some physical quantity indicates that the model is too simple and fails to include some crucial aspect of the real world.

 

Thus, while some cosmologists do not have a problem with assuming that our universe began in a singular state, most are convinced that the big bang singularity is an artefact - to be replaced by a more accurate description once quantum gravity research has made suitable progress. To be replaced with what? Nobody knows for sure. In some models, we can go infinitely far into the past (one example is presented in the spotlight text Avoiding the big bang). In others, the big bang is replaced by a beginning of the universe which avoids all infinities, but in which time itself is rather different from what we are used to (some more information about this can be found in the spotlight text Searching for the quantum beginning of the universe)."

http://www.einstein-online.info/spotlights/big_bangs/?set_language=en

 

"Misconceptions about the Big Bang

Forty years ago this July, scientists announced the discovery of definitive evidence for the expansion of the universe from a hotter, denser, primordial state. They had found the cool afterglow of the big bang: the cosmic microwave background radiation. Since this discovery, the expansion and cooling of the universe has been the unifying theme of cosmology, much as Darwinian evolution is the unifying theme of biology."

http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf

 

 

If laws of physics change when there is complete lack of evidence, there is no rule of the game anymore.

When we talk about the Bang event then we have gone beyond our current capabilities but when dealing with the evolution of the Universe from the "primeval atom" then it is well tested.

 

"Observational evidence

The earliest and most direct kinds of observational evidence are the Hubble-type expansion seen in the redshifts of galaxies, the detailed measurements of the cosmic microwave background, the abundance of light elements (see Big Bang nucleosynthesis), and today also the large scale distribution and apparent evolution of galaxies which are predicted to occur due to gravitational growth of structure in the standard theory. These are sometimes called "the four pillars of the Big Bang theory"."

http://en.wikipedia.org/wiki/Big_Bang

 

 

That is much confusing. All diagrams I know concerning the BBT have 2 axis, Space & Time. And there is a very accurate relationship between space & time. Space expands with time, and objects get closer to each other as much we go back in time.

Well, it depends of which Big Bang we are talking about, when speaking of the Big Bang theory then space is still expanding and we are still inside it and as such we are still located right on top of it today. If you mean the ignition of our Universe, the event of the Bang itself, then it happened ~13.7 billion years ago but at that time it happened to this place in space where we are located today too.

 

And since you posted the Image from Wiki and state that:

"And there is a very accurate relationship between space & time. Space expands with time, and objects get closer to each other as much we go back in time."

Then you must understand that space was smaller and not bigger in the past, as is contrary to your earlier statement:

"a universe wider and wider as much I look far away, and wider & wider as much I look in the past."

 

 

I agree that we don't know how distant they are now, but I don't understand why we don't know how distant they were back then when the light was emitted. To me, if they are in opposite directions, at the same distance, we must be able to calculate their mutual distance at the time light was emitted. And anyway what imports to this discussion is that those 2 galaxies, because they are at the same distance from us, are simultanate events.

As I have tried to explain, the Big Bang theory is about how the Universe has developed over time, we have models for how space has expanded and can calculate how far away they were when the light was emitted, but the distance we measure now only reveals how much space the image has traveled through to reach us. If space has expanded or contracted during the travel time of the image then the distance we measure from the travel time would not be accurate.

 

The important part is that when doing the calculations, the two galaxies were closer together in the past than what they seem to be and they are actually even more distanced today.

 

 

How can, we don't disagree at all! I never said it was a simulation of reversal time. If i did, sorry, not my intention. What i meant is that Universe was huuuuuuuuuge a long time ago, and that I cannot conceive it came out of a singularity. From the moment Sysiphus presents BB like an already-in-place-creation, it cancels everything, logic included.

Hmmm, you are arguing two different things at the same time. I suggest that you drop the singularity idea or other aspects of the "creation" itself which currently is beyound or at least on the border of our knowledge and instead concentrate on how the Universe changed from shortly after that moment to today.

(If you don't want to drop that question then try to separate them to avoid confusion.)

 

We don't know the size of the Universe, it could be infinite or huuuuuuuuuge like you say and we are only able to view a very tiny little part of it. But after the creation it was there in it's primeval state and nothing has been added or removed afterwards, the only changes are of configuration. And as such it could have been infinite or huuuuuuuuuge at that state, however we do know from observation that distances between objects is growing which leads to the conclusion that the Universe was more dense back in the remote past and is wider and more empty now.

 

I pointed out the reversal of time to make you think about how the Universe would appear differently in such a simulation instead of this movie where we travel further and further from Earth and see younger and younger features.

 

Logic says that since light has a finite speed then images from further distances has traveled longer in space and are therefor older, making the objects in it look younger than they do today.

 

Logic says that the Universe exists now and since light has a finite speed, then light will arrive here on Earth from more and more distant parts of the Universe as more and more time passes by.

 

Logic can not conclude from two totally different galaxies of different distance from us and thus of different ages, that the Universe must have been larger or smaller in the past.

 

Logic says that when from observation the Universe seems to be growing in size, then it must have been smaller a long time ago and will get bigger in the future.

 

 

Do you have any evidence to provide?

"Cosmological horizon

The cosmological horizon, (also known as the particle horizon) is the maximum distance from which particles could have traveled to the observer in the age of the universe. It represents the boundary between the observable and the unobservable regions of the universe. The existence, properties, and significance of a cosmological horizon depend on the particular cosmological model being discussed.

 

In terms of comoving distance, the particle horizon is equal to the conformal time η₀ that has passed since the Big Bang, times the speed of light c. The quantity η₀ is given by,

[math]\eta_0 = \int_{0}^{t_0}\frac{dt'}{a(t')}[/math]

 

where a(t) is the scale factor of the Friedmann-Lemaître-Robertson-Walker metric, and we have taken the Big Bang to be at t = 0. In other words, the particle horizon recedes constantly as time passes, and the observed fraction of the universe always increases.

 

The particle horizon differs from the event horizon in that the particle horizon represents the largest comoving distance from which light could have reached the observer by a specific time, while the event horizon is the largest comoving distance from which light emitted now can ever reach the observer."

http://en.wikipedia.org/wiki/Observable_universe

 

 

And how is it possible that the 'curtain" opened everywhere at the same time?

It has already been covered and explained twice but here is the explanation again:

 

"Recombination (cosmology)

In cosmology, recombination refers to the epoch at which charged electrons and protons in the universe first formed electrically neutral hydrogen atoms. After the Big Bang, the universe was a hot, dense plasma of photons, electrons, and protons. The interaction of photons with the plasma made the universe effectively opaque to radiation. As the universe expanded, it also cooled. Eventually, the universe cooled to the point that the formation of neutral hydrogen was energetically favored, and the fraction of free electrons and protons as compared to neutral hydrogen decreased to about 1 part in 10,000.

 

Shortly after, photons decoupled from matter in the universe, which leads to recombination sometimes being called photon decoupling, although recombination and photon decoupling are distinct events. Once photons decoupled from matter, they traveled freely through the universe without interacting with matter, and constitute what we observe today as cosmic microwave background radiation. Recombination occurred when the universe was roughly 380,000 years old, or at a redshift of z = 1,100."

http://en.wikipedia.org/wiki/Recombination_(cosmology)

 

 

If it is part of the horizon problem, it is not addressed in the wiki article.

The Horizon problem is dealing with why very different parts of the CMBR seems to have been connected in a remote past and yet they are separated with great distances.

Edited November 2, 2010 by Spyman

[michel123456]

thank you Spy for your time.

Instead of discussing one by one all of your points (I am sure it won't drive nowhere), I just want to explain my point and maybe why I disagree with the BBT.

 

You are describing the Universe like something much bigger than what we are observing, and I have no problem with that.

My problem begins when you are explaining that this Universe, much bigger than the observable one, is already in place when observation begins. IMHO it is a difficult point to swallow. But that is not the most important.

My problem gets crucial when I look at observations (the part of the story we can actually see): if I want to look in the past, I just have to look far away. The more far away I look, the bigger is the radius of the circle of the observable Universe. You can't disagree on that, you said exactly the same thing, more professionaly.

What I say is simply that the circle of the past is always bigger than the circle of the present. Is that so wrong? I thought it was almost tautology.

The small casserole is inside the big one, and the big one is the youngest. On this part of the curtain it is always true.

What BBT is about, is exactly the contrary. On the other side of the curtain, the small casserole contains the big one, and the small casserole is the youngest.

Where am I wrong?

 

Edited November 2, 2010 by michel123456

[Sisyphus]

If I write you a letter and you receive it a week later, does that mean I "am" a week in the past?

[michel123456]

Sorry to be unclear, I tried to focus on your statement that the Universe seems to be bigger in the past, of which you still don't seem to understand why it is wrong. I don't know how to explain it to you any better than what I already has done.

 

 

The observable universe.

The sketch is about If (IF) we could see behind the curtain.

 

If I write you a letter and you receive it a week later, does that mean I "am" a week in the past?

 

If your letter was a picture of you, the picture would represent you as you were a week ago.

The picture we get from the far away universe is that of a young man.

Edited November 2, 2010 by michel123456

[Sisyphus]

 

If your letter was a picture of you, the picture would represent you as you were a week ago.

The picture we get from the far away universe is that of a young man.

 

Yes, the picture. We get to see a larger portion of the universe as it was early on than we do as it was more recently.

 

To continue the analogy, suppose everyone in the world sends starts sending you letters every day. From the people in your own town, you get them the day after they send them. For nearby towns, two days, and so on. For most international mail, it takes a full week.

 

You look at your pile of billions of letters. Only a few thousand are from the day before, and the vast majority are from a week ago. "Wow," you say, "the world sure had a lot more people in it a week ago! That theory that the world's population is growing is ridiculous!"

[michel123456]

Yes, the picture. We get to see a larger portion of the universe as it was early on than we do as it was more recently.

 

To continue the analogy, suppose everyone in the world sends starts sending you letters every day. From the people in your own town, you get them the day after they send them. For nearby towns, two days, and so on. For most international mail, it takes a full week.

 

You look at your pile of billions of letters. Only a few thousand are from the day before, and the vast majority are from a week ago. "Wow," you say, "the world sure had a lot more people in it a week ago! That theory that the world's population is growing is ridiculous!"

 

I am not saying that the world population is growing. I simply say "wow, i got a lot of letters from a week ago". If i wait, i will get letters from 2 weeks ago, more letters, and so on and so on. It will not go downwards.

 

I have well understood your point. If the universe preexisted, and suddenly the light came of it, on such premises your explanation stands. The premises are under question. How could the whole Universe be enlighted simultanetly all around? IIRC simultaneity is not much compatible with Relativity. But this is not the place to discuss it.

My sketch above is a description of my point of vue. The observable universe is a sphere growing function of time. The more I look in the past, the larger is the observable universe. I cannot conceive a situation where the observable universe reduces to a singularity.

 

And I have to correct something: The picture we get from the far away universe is that of a young man (under the BBT). I will laugh when some future astronomer will find a distant three legs galaxy.

[pioneer]

With the mail analogy, the letters from distant towns, would not reflect what was happening in those distant town, the day you recieved their letters, but would reflect what had occurred in the past.

 

The data from that ancient galaxy tells us what that galaxy was doing 13 billion years ago. It tells us nothing about what it is doing today. If that galaxy made a U-turn 5 billions years ago and was now coming toward us, we would still see it moving away since it would take billions of years before the new data arrives.

 

If we look at the data we see, the most distant red shifts the most. That means the farther back in time we go the faster the universe was expanding. As we get closer in distance and therefore in time there is less red shift. This indicates that the universe is contracting since closer and closer in distance means closer and closer in time.

 

If the universe was expanding the most distant objects by being more distant in time should be less red shifted. That would mean when we go back to the oldest recorded time there was less expansion. As we go closer in distance and therefore in time, the red shift should increase to reflect expansion with time moving forward.

Edited November 2, 2010 by pioneer

[Sisyphus]

I am not saying that the world population is growing. I simply say "wow, i got a lot of letters from a week ago". If i wait, i will get letters from 2 weeks ago, more letters, and so on and so on. It will not go downwards.

 

No, you are saying that the world population is shrinking ("bigger in the past"), because you have more letters from a week ago than you do from yesterday.

 

I have well understood your point. If the universe preexisted, and suddenly the light came of it, on such premises your explanation stands. The premises are under question. How could the whole Universe be enlighted simultanetly all around? IIRC simultaneity is not much compatible with Relativity. But this is not the place to discuss it.

 

It was already explained how the universe became transparently nearly simultaneously all around. There is nothing in that that contradicts relativity - relativity merely states that events simultaneous in one reference frame are not simultaneous in another.

 

My sketch above is a description of my point of vue. The observable universe is a sphere growing function of time. The more I look in the past, the larger is the observable universe. I cannot conceive a situation where the observable universe reduces to a singularity.

 

Yes, and most of your letters were written before yesterday. I do not understand why this a problem for you.

[michel123456]

With the mail analogy, the letters from distant towns, would not reflect what was happening in those distant town, the day you recieved their letters, but would reflect what had occurred in the past.

 

The data from that ancient galaxy tells us what that galaxy was doing 13 billion years ago. It tells us nothing about what it is doing today. If that galaxy made a U-turn 5 billions years ago and was now coming toward us, we would still see it moving away since it would take billions of years before the new data arrives.

 

If we look at the data we see, the most distant red shifts the most. That means the farther back in time we go the faster the universe was expanding. As we get closer in distance and therefore in time there is less red shift. This indicates that the universe is contracting since closer and closer in distance means closer and closer in time.

 

If the universe was expanding the most distant objects by being more distant in time should be less red shifted. That would mean when we go back to the oldest recorded time there was less expansion. As we go closer in distance and therefore in time, the red shift should increase to reflect expansion with time moving forward.

 

It looks correct to me. I don't understand why Sysiphus don't come and burn you.

[Spyman]

What I say is simply that the circle of the past is always bigger than the circle of the present.

The circle of the past view is always bigger than the circle of the present view, but that doesn't prove that the circle emitting the past view actually was physically bigger in the past than what it is now in the present.

 

 

Where am I wrong?

Let's make a thought experiment:

 

What if we run a huge map pin straight through the Earth, locking it from rotation and firmly secure its position in space. Attached to the pin we have a rigid steel chain reaching 10 billion lightyears out into empty space. In the middle and at the far end of the chain we weld tight in place identical space probes. The probes constantly beams down video feeds of their clocks, which are synchronized to Earth time. After 10 billion years we can start to recieve two video feeds revealing one clock running 5 billion years late and one clock running 10 billion years late.

 

Now tell me, why do you think the length of the chain is shrinking over time ?

 

 

----------

 

 

With the mail analogy, the letters from distant towns, would not reflect what was happening in those distant town, the day you recieved their letters, but would reflect what had occurred in the past.

Agree.

 

 

The data from that ancient galaxy tells us what that galaxy was doing 13 billion years ago. It tells us nothing about what it is doing today. If that galaxy made a U-turn 5 billions years ago and was now coming toward us, we would still see it moving away since it would take billions of years before the new data arrives.

Agree.

 

 

If we look at the data we see, the most distant red shifts the most. That means the farther back in time we go the faster the universe was expanding. As we get closer in distance and therefore in time there is less red shift. This indicates that the universe is contracting since closer and closer in distance means closer and closer in time.

No, that would only indicate that the Universe is expanding less, at a slower rate with a smaller redshift. If the Universe starts to contract we will observe blueshifts.

 

 

If the universe was expanding the most distant objects by being more distant in time should be less red shifted. That would mean when we go back to the oldest recorded time there was less expansion. As we go closer in distance and therefore in time, the red shift should increase to reflect expansion with time moving forward.

No, that doesn't make any sense at all, there is no reason that more distant objects should be less redshifted when the Universe is expanding, the amount of red/blue-shift indicates how fast the Universe was changing at that time and not if it actually was physically bigger or smaller.

Edited November 3, 2010 by Spyman

[michel123456]

The circle of the past view is always bigger than the circle of the present view, but that doesn't prove that the circle emitting the past view actually was physically bigger in the past than what it is now in the present.

 

Correct. That doesn't prove that the circle emitting the past view actually was physically bigger in the past. But IF the past Real Universe was shrinking (looking backward at its expansion), and IF it would be observable, the Observable Universe would be shrinking too. Because the Observable Universe is an open book of what happened in the past. The 'trick" of the BB is to put a curtain exactly at the moment where we should observe the theoretical shrinking (looking backward at its expansion).

 

If you put into a diagram the diameter of the Observable universe versus time, it is always increasing. The BBT consists of telling us that at some time very distant from us and inobservable, the Real Universe gets smaller than the Observable Universe to the point of reaching a singularity. In the diagram, that means a sudden change in orientation, and I really don't see any reason why I should believe such a nonsense Theory.

 

I understand nothing of your Thought experiment, I think it is confusing.

[between3and26characterslon]

Correct. That doesn't prove that the circle emitting the past view actually was physically bigger in the past. But IF the past Real Universe was shrinking (looking backward at its expansion), and IF it would be observable, the Observable Universe would be shrinking too. Because the Observable Universe is an open book of what happened in the past. The 'trick" of the BB is to put a curtain exactly at the moment where we should observe the theoretical shrinking (looking backward at its expansion).

 

If you put into a diagram the diameter of the Observable universe versus time, it is always increasing. The BBT consists of telling us that at some time very distant from us and inobservable, the Real Universe gets smaller than the Observable Universe to the point of reaching a singularity. In the diagram, that means a sudden change in orientation, and I really don't see any reason why I should believe such a nonsense Theory.

 

I understand nothing of your Thought experiment, I think it is confusing.

 

 

What would a singularity look like from the inside?

[Spyman]

... and I really don't see any reason why I should believe such a nonsense Theory.

Instead of discussing the ridiculous confusing nonsense of Horror, (I am sure it won't drive nowhere), I just want to point out that I agree, I don't see any reason for you to put faith in anything you don't understand.

 

But, IMHO without the knowledge you are not qualified to judge it either.

Edited November 3, 2010 by Spyman

[michel123456]

This picture has been edited.

Edited November 3, 2010 by michel123456

[pioneer]

Say I was 10 light years away and sent a picture of myself to earth. The signal takes 10 years to reach the earth. What the earth sees is a picture of me 10 years ago. This tells nothing of today but only what I looked like 10 years ago. If we assume we can predict the future it is a crap shoot without an energy balance.

 

One of the problem relative reference can create is a violation of energy conservation. SR has three eqautions, one for mass, one for distance and one for time. Although space-time references can be relative for moving references, mass can not be relative or else we could never complete an energy balance.

 

For example, I am sitting on a train moving at V looking out the window. Another person is at the station watching the train go by at V. We can use relative reference and call either person v=0. However, if we try to do an energy balance, mass/energy adds up different for each reference. The one on the train sees the landscape appear to move, which will take much more energy than the reference that will see the train move. We can create extra energy for the universe if we decide we like the train reference, since reference is relative, right?

 

If our reference choice creates energy out of the void ....

Edited November 3, 2010 by pioneer