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R J Leahey
2008-Apr-07, 12:49 PM
if a ship traveling just under light speed for one thousand years has one billion years pass on the earth,then the universe must only be a fraction of the stated age that I have read on this site.I'm not a science major, just a guy asking a question.

antoniseb
2008-Apr-07, 01:07 PM
if a ship traveling just under light speed for one thousand years has one billion years pass on the earth,then the universe must only be a fraction of the stated age that I have read on this site.I'm not a science major, just a guy asking a question.

Can you elaborate on why you think this?

NEOWatcher
2008-Apr-07, 01:08 PM
Slice and dice the interpretations all you want. But; we live in a time frame, and we use that time frame.

Let's say a civilization is travelling at some speed to make thier relative time to be a thousand years in our existance. To them, it may be a short time when checking atomic or physical means. But; they still will have observed a slice of early time that corresponds to billions of orbits of the Earth.*

They would just be seeing it in what we would consider a warped view, but to them is normal.

So; the universe is the same age in any time frame, it's just the perception of what that time frame is that's different.

*Add... Of course thier distance is going to alter exactly what that slice is and how it's distorted.

Motor Daddy
2008-Apr-07, 01:51 PM
Depends what you call "the universe."

To me, there is infinite space in every direction, and in that infinite space is mass that is in constant motion.

That means there is mass, there is distance, and there is time. Time is the interval it takes for a predefined object to travel a predefined distance. How would you measure that interval? Well, you set a standard interval of another mass in motion, and you use that as the standard to compare all other motion to.

The problem is, you can't go from nothing to something just as you can't go from something to nothing.

To me, the universe could have never began, just as it could never end. You can't create or destroy energy.

Extrapolating data from a current state back to a singularity is no more accurate than if you tried to extrapolate the data of a car traveling down a highway at 60 MPH and saying the car has been traveling on the highway X amount of time, and that it began it's journey at the beginning of the highway X amount of time ago.

Just one problem, what if the car was continuously driving, and took an entrance ramp to the highway somewhere other than the beginning of the highway?

The big bang is useless to me, as even if there were a "singularity" at one "time", it certainly did not just "appear" from nothing. You can not create energy and you can not destroy it.

It is impossible to go from zero to one, and likewise impossible to go from one to zero. In other words, the "universe" was neither created nor will it be destroyed. Time never "began" and time will never "end." One thing is certain, though, the universe will continue to remain in continuous motion, which means continuous change, which means continuous evolution.

Cougar
2008-Apr-07, 02:06 PM
...what if the car was continuously driving, and took an entrance ramp to the highway somewhere other than the beginning of the highway?
Do you have any evidence of such an entrance ramp?


The big bang is useless to me, as even if there were a "singularity" at one "time", it certainly did not just "appear" from nothing.
The Big Bang theory doesn't say it did.

Ken G
2008-Apr-07, 02:09 PM
if a ship traveling just under light speed for one thousand years has one billion years pass on the earth,then the universe must only be a fraction of the stated age that I have read on this site.The "age of the universe" does not necessarily apply to all the matter in it, but rather to the "average" behavior. But the average particle is not moving near c relative to its immediate environment, so the difference is usually unimportant. You are probably imagining that material very far from us is moving at close to c, but it is not moving at near c relative to its nearby matter, and that's what counts. The expanding universe does not make time run more slowly in some vast regions relative to others, it is governed by the "cosmological principle" that says the universe is doing the same thing everywhere. That also means time is elapsing the same everywhere.

Or an even better way to think of it, all matter has its own "proper time" and therefore its own "proper age", but all the matter in our vicinity is moving at nearly the same speed as we are, so its proper age is 13.7 billion years, like ours. For distant places, it depends on what we choose to call "now", and we simply choose that same proper age of the average material to be 13.7 billion years also-- that's our "now" extended to include them. And sure enough, all the same kinds of things are happening at their proper age of 13.7 billion years as at ours. This way of looking at things is called "comoving coordinates".

Tim Thompson
2008-Apr-07, 02:18 PM
if a ship traveling just under light speed for one thousand years has one billion years pass on the earth, then the universe must only be a fraction of the stated age that I have read on this site. ...
You are certainly not the only one to be confused by relativity and time. So if we have one clock on the ship, and another clock on Earth, which one is "real"? Neither one. Both clocks are equally "real" in every physical sense. The clock on the ship is certainly "real" as far as the people on the ship care, and certainly everyone on Earth does just fine with the Earth clock. Time dilation, the part of special relativity that has clocks go slower time-wise as they go faster speed-wise is a key to comparing different clocks relative to each other, but it does not single out either as being "real" in any absolute sense. The only time that is "real" for any observer is the time measured by a clock at rest with respect to the observer. Any other time, like the time we see on some other clock over there, moving with respect to us, is called a coordinate time, and is not "real" for us.

But there is an absolute, invariant time in general relativity, called the proper time. This is the time measured by a clock in free fall, and an observer at rest with respect to that clock. There is no way to measure the age of the universe, it can only be derived from a cosmological model. The age of the universe reported by cosmologists, like the 13.7 billion years implied by the WMAP project, is a proper time, and represents the time ticked off by a clock in free fall from the bang to here & now.

John Mendenhall
2008-Apr-07, 02:23 PM
For distant places, it depends on what we choose to call "now", and we simply choose that same proper age of the average material to be 13.7 billion years also-- that's our "now" extended to include them. And sure enough, all the same kinds of things are happening at their proper age of 13.7 billion years as at ours. This way of looking at things is called "comoving coordinates".



And on what we choose to call distant. Even looking at objects billions of light years away, and knowing that it has taken that long for the light to reach us, we see that the same physical processes are taking place, obeying the same laws we see operating around us.

Motor Daddy
2008-Apr-07, 02:27 PM
The "age of the universe" does not necessarily apply to all the matter in it, but rather to the "average" behavior. But the average particle is not moving near c relative to its immediate environment, so the difference is usually unimportant. You are probably imagining that material very far from us is moving at close to c, but it is not moving at near c relative to its nearby matter, and that's what counts. The expanding universe does not make time run more slowly in some vast regions relative to others, it is governed by the "cosmological principle" that says the universe is doing the same thing everywhere. That also means time is elapsing the same everywhere.

Or an even better way to think of it, all matter has its own "proper time" and therefore its own "proper age", but all the matter in our vicinity is moving at nearly the same speed as we are, so its proper age is 13.7 billion years, like ours. For distant places, it depends on what we choose to call "now", and we simply choose that same proper age of the average material to be 13.7 billion years also-- that's our "now" extended to include them. And sure enough, all the same kinds of things are happening at their proper age of 13.7 billion years as at ours. This way of looking at things is called "comoving coordinates".

So what was in space 500 trillion years ago? Nothing? Just "empty space?" Are you saying the universe was simply "created" from empty space roughly 13.7 billion years ago, and that all the energy of our universe was "created from empty space?"

Motor Daddy
2008-Apr-07, 02:46 PM
Do you have any evidence of such an entrance ramp?

Why should I assume the car entered the highway at the beginning? I'm saying it could have entered ANYWHERE. You are saying it entered at the beginning, as if that were known. You can't even define the beginning of the highway, because there is no beginning.

Cougar
2008-Apr-07, 03:19 PM
Why should I assume the car entered the highway at the beginning? I'm saying it could have entered ANYWHERE. You are saying it entered at the beginning, as if that were known.
Actually, there is very good evidence that "the car was on the highway" very near the beginning of that highway. The observed abundances of the light elements throughout the universe match what is predicted if the car was on the highway very near the beginning. If the car came on a later onramp, there would be no way to make the roughly 25% helium that we observe throughout the universe. It could only have been made back near the beginning of the road. See here (http://www.talkorigins.org/faqs/astronomy/bigbang.html#lightelements), or for more detail, here (http://www.astro.ucla.edu/~wright/BBNS.html).

Note: We call it the "beginning" because it was the beginning of the universe we know about. What may or may not have been existing at or before our beginning, if there was a before, we don't currently know anything about, and we may never.

Motor Daddy
2008-Apr-07, 03:32 PM
Note: We call it the "beginning" because it was the beginning of the universe we know about. What may or may not have been existing at or before our beginning, if there was a before, we don't currently know anything about, and we may never.

Exactly my point. Why pick a user defined "instant" in time and say "that is the beginning?" That's no more valid than defining the beginning of an ice cube. When did the ice cube begin? Did it begin 4 hours after placing an ice cube tray full of water in the freezer? NO. Did it begin 2 minutes after placing in the freezer? NO! Did it begin when you filled the tray with water? NO. Did it begin as a rain drop? NO! Did it begin when two hydrogen atoms bonded with one oxygen atom? NO. etc etc etc...

There is no beginning to an ice cube, just as there is no beginning to the universe.

You can't make something from nothing. You can continuously evolve, though.

CodeSlinger
2008-Apr-07, 03:45 PM
MD,

Back in comment #5, Cougar has already pointed out that Big Bang does not say "the universe came from nothing." What it does say is essentially that the current universe as we know it, which includes all the laws of physics, started as something very small, very hot and very dense 13.7 billion years ago, and has been expanding ever since. When we refer to that as the beginning of the universe, what's really meant is "the beginning of the universe as we know it." Big Bang makes no claims as to what did or did not exist prior to that "beginning", because we simply don't have enough information to say, one way or the other. When you try to object to Big Bang by saying "you can't make something from nothing", you're only swatting at a strawman, because Big Bang does not say the universe came from nothing.

Motor Daddy
2008-Apr-07, 03:53 PM
MD,

Back in comment #5, Cougar has already pointed out that Big Bang does not say "the universe came from nothing." What it does say is essentially that the current universe as we know it, which includes all the laws of physics, started as something very small, very hot and very dense 13.7 billion years ago, and has been expanding ever since. Big Bang makes no claims as to what did or did not exist prior to that. When you try to object to Big Bang by saying "you can't make something from nothing", you're only swatting at a strawman, because Big Bang does not say the universe came from nothing.

I didn't say the Big Bang says the universe comes from nothing. I said pointing to a singularity and "starting the clock" from that "instant" (whatever that means) is simply pointing to a specific state of the universe and calling that "the beginning" because you don't know what was before that, and surely there was a "before", because something doesn't come from nothing.

CodeSlinger
2008-Apr-07, 04:01 PM
"Something doesn't come from nothing" is only a rule derived from what we have observed thus far in our current universe. There is no reason to think that these rules, which only came into being with our current universe, necessarily holds for whatever there might have been before our current universe took shape.

John Mendenhall
2008-Apr-07, 04:22 PM
So for the last half dozen or so posts, despite superficial differences, we all agree that a long time ago the universe was hot, dense, and our macro physical laws break down, and quantum mechanics isn't doing too jet hot, either - and we have a singularity. May as well start counting from there, right? Especially since the model fits what we observe so well.

Now if the string people can make some testable predictions, maybe we could make some progress on the singularity.

cosmocrazy
2008-Apr-07, 04:24 PM
I didn't say the Big Bang says the universe comes from nothing. I said pointing to a singularity and "starting the clock" from that "instant" (whatever that means) is simply pointing to a specific state of the universe and calling that "the beginning" because you don't know what was before that, and surely there was a "before", because something doesn't come from nothing.

You could describe that point as starting the clock for our universe if you consider the big bang to have come from a singularity which was created by a massive black hole formed in a different universe, which punched its way into the fabric of space our universe evolves in today. It has been hypothesized that all the known forces/matter and dimensions as we know them are melded into one, including time. We are unable to imagine this point because this concept is beyond our imagination! what this may suggest is that it could be an infinite on going cycle, but that there will be an instant for every universe at which everything starts to evolve including time.

captain swoop
2008-Apr-07, 04:44 PM
As for the ice cube, surely it started when the first ice crystal formed.

cosmocrazy
2008-Apr-07, 05:06 PM
[QUOTE=John Mendenhall;1212177]So for the last half dozen or so posts, despite superficial differences, we all agree that a long time ago the universe was hot, dense, and our macro physical laws break down, and quantum mechanics isn't doing too jet hot, either - and we have a singularity. May as well start counting from there, right? Especially since the model fits what we observe so well.

I agree we may as well start from somewhere! and where better than the point shortly after the big bang when the universe as we see it starts to form (i.e. simply atoms starting to form). I think though that it is theorized that gravity became separate from the singularity less than a billionth of a second after the initial instant of expansion. close enough for us to use as the beginning of our universe!

Motor Daddy
2008-Apr-07, 05:06 PM
You could describe that point as starting the clock for our universe if you consider the big bang to have come from a singularity which was created by a massive black hole formed in a different universe, which punched its way into the fabric of space our universe evolves in today. It has been hypothesized that all the known forces/matter and dimensions as we know them are melded into one, including time. We are unable to imagine this point because this concept is beyond our imagination! what this may suggest is that it could be an infinite on going cycle, but that there will be an instant for every universe at which everything starts to evolve including time.

And again, I have to question the "logic" of starting time from a specific state of the universe. Mass, distance and time has always existed and always will, it is inevitable, as proof of it existing today and not being able to create or destroy energy (time).

We know energy is here today, and we know energy can not be created or destroyed, only changed. That means time never began and time will never end, so why pick a point as if there were an "instant" and say that is the "beginning?"

A second hand of infinite length from an axis is in constant continuous motion (constant velocity) of 1 RPM. I put a red dot on the second hand at 1 foot away from the axis. The red dot travels 6.2832 feet per minute, or .10472 feet per second.

So you think by mathematically dividing the time and distance equally you can show that the dot is in a specific place at a specific time, creating the illusion of an "instant?" PROVE IT, because you can keep dividing the time and distance for infinity, I can also show that as you try and show the second hand is in any given place at any given time, I can show that as you divide the time and distance of that point, I can pick a point on the infinite second hand that is proportionally further away from the axis and show that no matter how close you get to approaching an "instant", that, in fact, the motion never changes. What does that mean? It means that "time" travels away from the axis just as it does travel distance at any given "choosen" point on the second hand.

In other words, you keep dividing the distance and time, and I'll keep multiplying the distance away from the axis proportionally, and you will never show that the second hand was in one place at one "time."

cosmocrazy
2008-Apr-07, 05:10 PM
As for the ice cube, surely it started when the first ice crystal formed.

Or you could go fundamental and say it started to form when the first atom formed contained in the water making up the ice cube! hee hee

selden
2008-Apr-07, 05:27 PM
Motor Daddy,

You are describing your interpretation of space-time as you experience it today.

We do not know what it was or even if it existed before the "big bang".

Motor Daddy
2008-Apr-07, 05:30 PM
Motor Daddy,

You are describing your interpretation of space-time as you experience it today.

We do not know what it was or even if it existed before the "big bang".

Was there energy before the Big Bang?

Did that energy have motion?

Does motion have time?

CodeSlinger
2008-Apr-07, 05:33 PM
Was there energy before the Big Bang?

Did that energy have motion?

Does motion have time?

Don't know, don't know, and don't know. You can believe whatever you like about what there was before the Big Bang. But know that there is currently no scientific basis for making any definite statements about how things were or were not prior to the Big Bang.

cosmocrazy
2008-Apr-07, 05:35 PM
And again, I have to question the "logic" of starting time from a specific state of the universe. Mass, distance and time has always existed and always will, it is inevitable, as proof of it existing today and not being able to create or destroy energy (time).


I agree with what you are saying regarding the evolving state and form of our universe as we see it. And i agree that it is not possible for us to pin point any one moment in time and space as a fixed reference point - simply because everything is in constant motion. The idea i was trying to put forward was that a long time ago it has been theorized that if the big bang is to be assumed correct then at the initial singularity all maths, logic and common sense breaks down.
I was suggesting that the universe is in an infinite evolving state and that our universe as we see it began its evolution at the singularity. Prior to that it the singularity could have been formed at the center of a black hole which in turn evolved from matter and energy which was sucked into it, which in turn came from an evolving universe and so on creating an infinite cycle which has no beginning or end but goes from one state to another. The problem is for us to make sense of how our universe is evolving then we need a reference point at which to start from. Suggesting we look for hard evidence of what happened before the singularity ( if that is what existed before the initial expansion/evolution ) is possibly useless to us because all the known laws of physics breakdown at that point and what created the singularity in the first place could have had totally different fundamental laws and logic.

mugaliens
2008-Apr-07, 05:46 PM
Interesting question. There's a difference between the "observable universe (http://en.wikipedia.org/wiki/Observable_universe)" and the "universe (http://en.wikipedia.org/wiki/Universe)."

The edge of the first is 13.7 Billion years in radius away from us, as we observe it.

However, since space-time has been expanding during this time, the actual "distances" involved get a bit more complicated! Many threads have been created on BAUT about this phenomenon. However, I think the two links I just included will give you something to chew on for a while.

cosmocrazy
2008-Apr-07, 05:48 PM
Was there energy before the Big Bang?

Did that energy have motion?

Does motion have time?

Q. Was there energy before the Big Bang?

A. Possibly but maybe not as we know it.

Q. Did that energy have motion?

A. Maybe only from the intial moment of expansion

Q. Does motion have time?

A. Motion requires time to exist (certainly as we know it)

Motor Daddy
2008-Apr-07, 05:56 PM
I was suggesting that the universe is in an infinite evolving state and that our universe as we see it began its evolution at the singularity.

And this is the idea that I have a problem with. The universe didn't BEGIN its evolution as a singularity. If there ever was a singularity, that was just part of the evolution of energy. Starting "time" at a singularity implies there was no "time" before the singularity, which suggest the singularity was created from "nothing", and that simply didn't happen.

We already created a reference point for time. BC was everything before Christ. Go back as far as you like. 10^500 years BC is fine with me. :lol:

cosmocrazy
2008-Apr-07, 05:57 PM
Interesting question. There's a difference between the "observable universe (http://en.wikipedia.org/wiki/Observable_universe)" and the "universe (http://en.wikipedia.org/wiki/Universe)."

The edge of the first is 13.7 Billion years in radius away from us, as we observe it.

However, since space-time has been expanding during this time, the actual "distances" involved get a bit more complicated! Many threads have been created on BAUT about this phenomenon. However, I think the two links I just included will give you something to chew on for a while.

A nice point made! we can only estimate the size and age of our observable universe using the initial expansion point as the start. But really this is only our perceived reality, not actually the true reality - a fact that we may never be able to know!

NEOWatcher
2008-Apr-07, 06:08 PM
And this is the idea that I have a problem with. The universe didn't BEGIN its evolution as a singularity. If there ever was a singularity, that was just part of the evolution of energy.
Our observations and mathematics implies that it started that way because all the projections converge at that point.


We already created a reference point for time. BC was everything before Christ. Go back as far as you like. 10^500 years BC is fine with me. :lol:
That would be like saying "we already created a temperature scale starting at zero for the point of freezing water".

But; science tells us that nothing can be below 0 degrees Kelvin because the activity of freezing gases all project to that point. We've never had 0 degrees Kelvin, we don't know what happens there (I think), but we know that 0 degrees Kelvin is the absolute minimum.

There may be some incredibly, far out, unknown physics to get below that. But; not with what we know.

cosmocrazy
2008-Apr-07, 06:15 PM
And this is the idea that I have a problem with. The universe didn't BEGIN its evolution as a singularity. If there ever was a singularity, that was just part of the evolution of energy. Starting "time" at a singularity implies there was no "time" before the singularity, which suggest the singularity was created from "nothing", and that simply didn't happen.

We already created a reference point for time. BC was everything before Christ. Go back as far as you like. 10^500 years BC is fine with me. :lol:

"The universe didn't BEGIN its evolution as a singularity" is only your personal opinion. You or anybody else does not know the answer to that one, it is just a theory.
But time could have been going on and continue forever with no beginning and no end. Or time as we know it could have started at the initial point of our expanding universe. All i,m saying is that like the reference point used in modern dating ( AD & BC ) we use the estimated initial moment of expansion of our universe as the reference point to calculate the age of our observable universe in the form we know it i.e matter & energy! prior to this point if the big bang theory is correct then any measurement is useless to us. If the big bang theory is incorrect and matter and energy just exists then it has no age because it exists in infinite time. But again this would be of no use to us to evaluate the evolution of our universe because to understand the nature of matter and energy we need to try and understand how it came to evolve in the form it is now! which means we need a starting reference point. If we don't try and look back and theorize about the formation of our universe then we may as well just conclude it is the way it is because it is, always was always will be!

Motor Daddy
2008-Apr-07, 06:33 PM
"The universe didn't BEGIN its evolution as a singularity" is only your personal opinion. You or anybody else does not know the answer to that one, it is just a theory.
But time could have been going on and continue forever with no beginning and no end. Or time as we know it could have started at the initial point of our expanding universe. All i,m saying is that like the reference point used in modern dating ( AD & BC ) we use the estimated initial moment of expansion of our universe as the reference point to calculate the age of our observable universe in the form we know it i.e matter & energy! prior to this point if the big bang theory is correct then any measurement is useless to us. If the big bang theory is incorrect and matter and energy just exists then it has no age because it exists in infinite time. But again this would be of no use to us to evaluate the evolution of our universe because to understand the nature of matter and energy we need to try and understand how it came to evolve in the form it is now! which means we need a starting reference point. If we don't try and look back and theorize about the formation of our universe then we may as well just conclude it is the way it is because it is, always was always will be!

So later, when we understand how the theoretical "singularity" evolved into what it was, and later understand the state of space before the singularity, should we then refer to that time as ** (Before Singularity)? :lol:

Now I'm confused. The year 4045 is roughly 4,045 from Christ's birth, 5,045 years after 1,000 BC, 13,700,002,045 years after the singularity (if the year 2,000 was 13.7 billion years old), and 15,700,002,045 years after 2,000,000,000 **. The year 2,000,000,000 ** is actually 15,699,998,000 BC. ;)

cosmocrazy
2008-Apr-07, 06:50 PM
:lol:[QUOTE=Motor Daddy;1212303]So later, when we understand how the theoretical "singularity" evolved into what it was, and later understand the state of space before the singularity, should we then refer to that time as ** (Before Singularity)?QUOTE ]

Yes exactly right! it can be considered just a reference point rather than the beginning of time! the moment in time that matter and energy began its evolution into the form we observe today! if we discover what happened prior to the singularity then we can say this is the state of our universe prior to its new evolution! from childhood to puberty! hee hee :lol:

The point I'm trying to get across is regardless whether time began at the singularity or not, it is a good point to start our understanding of the formation of matter/energy and the evolution of our observable universe as it is now. 14billion years ABB! :lol:

pzkpfw
2008-Apr-07, 09:07 PM
Just to put a "picture" on it:

People tend to think:

BB = nothing --> big bang --> Universe

But my understanding is that it's more like:

BB = don't know --> don't know --> singularity --> big bang --> expanding Universe

That about it?

cosmocrazy
2008-Apr-07, 09:13 PM
Just to put a "picture" on it:

People tend to think:

BB = nothing --> big bang --> Universe

But my understanding is that it's more like:

BB = don't know --> don't know --> singularity --> big bang --> expanding Universe

That about it?

Basically yes! if we did know more this thread would have gone in a different direction! :lol:

Ken G
2008-Apr-07, 09:36 PM
But my understanding is that it's more like:

BB = don't know --> don't know --> singularity --> big bang --> expanding Universe
I would have said simply
BB = don't know --> expanding universe.
None of the other steps are saying anything, nor are part of that theory.

cosmocrazy
2008-Apr-07, 09:47 PM
I would have said simply
BB = don't know --> expanding universe.
None of the other steps are saying anything, nor are part of that theory.

I missed that one. Well spotted Ken!, the big bang and the singularity are hypothetical theories based upon the current model of our expanding universe.

Cougar
2008-Apr-08, 03:06 AM
The singularity is not a theory. It's like deriving an expression and finding you have to divide by zero - something's wrong; this doesn't make sense; this is impossible. It heralds the break down of the theory that led to it, namely the general theory of relativity. (Well, Einstein's equations do not specify the universe; rather they may be considered a general framework within which you can construct many different model universes*.) As Tony Rothman (http://www.physics.princeton.edu/~trothman/) wrote....


"We mentioned that the FLRW cosmology begins with a singularity. This is a much more serious breakdown than a flat tire or a cracked engine block. It is, in fact, a physical impossibility -- a region where the laws of physics break down altogether and even spacetime comes to an end."

That's why there's so much interest in trying to come up with a theory of quantum gravity - to transcend GTR and QM.

* Rothman said that, too.

CosmosGP
2008-Apr-12, 12:34 AM
Our observations and mathematics implies that it started that way because all the projections converge at that point.

Then why do astronomers say that the big bang happened everywhere all at once?
All matter and time happened all of a sudden everywhere in the universe out to infinity? The story sais that it started at one point and all of a sudden it happened everywhere all at once! Please explain this bizzar theory?

I'm sorry, but if you start at a singularity that contradicts this theory.

I also think "expansion" that happened early in the BB was hypothisized to explain the smoothness of the CMB.

CosmosGP
2008-Apr-12, 12:35 AM
Our observations and mathematics implies that it started that way because all the projections converge at that point.

Then why do astronomers say that the big bang happened everywhere all at once?
All matter and time happened all of a sudden everywhere in the universe out to infinity? The story says that it started at one point and all of a sudden it happened everywhere all at once! Please explain this bizzaar theory?

I'm sorry, but if you start at a singularity that contradicts this theory.

I also think "expansion" that happened early in the BB was hypothisized to explain the smoothness of the CMB.

Jeff Root
2008-Apr-12, 01:41 AM
Our observations and mathematics implies that it started that way
because all the projections converge at that point.
Then why do astronomers say that the big bang happened everywhere
all at once?
This question has been answered here in Q&A many times, but
answering it again shouldn't hurt anything.

The singularity was a point in time. Extrapolating back in time, the
matter that constitutes everything we can see in the Universe must
have all been packed very tightly together about 13.7 billion years ago.
That point in time is the singularity at which the expansion of the
Universe began. If there was anything before that time, we have
no observational evidence of it, and no theory to tell us what it was.

I personally suspect that the Universe did not come into existence
instantaneously, but instead came into existence over some period
of time. The observed abundances of nuclear isotopes generated in
the first three minutes indicate that it had to be a very short period
of time, though -- a few seconds, at most.

So whether the Universe came into existence instantaneously or over
the course of a few seconds, it was initially very compact.

As the Universe expanded, bits of matter that were originally very far
apart got even farther apart, while bits of matter that were originally
very close together stayed close together.

The matter that eventually formed the stars and planets and nebulae
of the Milky Way galaxy was close together at the beginning. Gravity
kept it together as the Universe expanded.

Exactly the same is true for all galaxies throughout all of space. Each
galaxy is kept together by gravity, while galaxies that are far apart
from one another continue to get even farther and farther apart.

The view from any galaxy is similar: Nomatter where you are in the
Universe, you see the distant galaxies moving away from you. The
farther away from you a galaxy is, the faster it is moving away.

So there is no particular place that is the center of the Universe, or
the center of the expansion. Any point can be treated as if it were
the center with equal validity.

The size of the Universe is unknown. It is certainly larger than we are
able to see. What we are able to see is absurdly enormous. It could
be that the Universe is infinite. That seems nonsense to me, but there
is no actual observational evidence that it is not infinite. And likewise
no evidence that it is infinite.

-- Jeff, in Minneapolis

Cougar
2008-Apr-13, 03:45 PM
...is only your personal opinion. You or anybody else does not know the answer to that one, it is just a theory.
Oh, using "just a theory" as a sneer on someone's ill-formulated hypothesis is... poor use of the term. "Theories" in science typically have a tremendous amount of supporting evidence, not to mention confirmed predictions. If you want to criticize someone's proposal, say how it's not even a theory. ;)