Big Bang- where did the "original particle" come from?

[Lord Kenneth]

I don't know too much about the big bang, which is exaclty why I am asking.

Please, fill me in. I have been meaning to know for a long time now...

Where did the original particle-thing that trigged the big bang come from? Was it always there? Did it not come from "anything", so to speak?

[Hellbound]

Currently, it's an unanswerable question. According to current theory, there is no way any information could have been passed from "before" the big bang. We cannot even say that time or space existed before the big bang, or even that there was a before in any sense that we could comprehend it. It is completely unfathomable territory, with no known way to find out. Basically, that particle is as far back as we can go.

Now, that aside, some of the new theories have made some suggestions about this. One that I found interesting had to do with M-theory, a suggested that there was a minimum size possible. Basically, because of changes in physical constants and a lot of math that I couldn't quite follow exactly, the Plank length was suggested as the minimum possible size for the universe. As the math works out, a universe of size R/1 (with 1 being the plank length) is indistinguishable from a universe with a size of 1/R. This sort of supports the oscillating universe idea (bang, expansion, contraction, crunch, next bang, etc). I don't know all the theory and math behind it, and I believe there's a new theory now that's thought to have mnore promise than M-theory, so perhaps some others can shed more light on this :)

What are the coordinates where the Big Bang took place?

[shanek]

Originally posted by Whodini
What are the coordinates where the Big Bang took place?

Isn't that like asking for the longitude and latitude of the Earth's core?

[DanishDynamite]

shanek:Isn't that like asking for the longitude and latitude of the Earth's core? :eek: This. Is. Amazing. You have made a remark with which I can't possibly disagree. :)

[jj]

I think "nowhere" is the operative term, it was probably that such a collection of mass-energy would emerge at some point from nothing due to quantum froth.

Now why the quantum froth is another question.

Originally posted by Dark Cobra
I don't know too much about the big bang, which is exaclty why I am asking.

Please, fill me in. I have been meaning to know for a long time now...

Where did the original particle-thing that trigged the big bang come from? Was it always there? Did it not come from "anything", so to speak? I would ask pi but as she is currently studying I won't disturb her much as she would love me too, but I think she said the big bang started when nothing exploded, and the universe began. I for one cannot recall accurately what the theory is called or the exact desciption she gave, I will edit it as I find out how wrong I am.

try here (http://www.ppd.clrc.ac.uk/pub/bigbang/part1.html) One site I know pi spends time in alot.

Originally posted by shanek


Isn't that like asking for the longitude and latitude of the Earth's core?


I don't know.

If we can detect the background radiation, and have these expansionary models, etc., can't we locate where the Big Bang started, where everything is explanding from?

I don't know.

[kedo1981]

All we have to do is set our “transporter” navigation controls to “0” “0” “0”
and there we be.

Seriously though; all that I’ve read lately (Universe in a nutshell) leads my half wit mind to believe the term “Big Bang” is one of the worst scientific metaphors ever dreamed up.
It leads to images of a titanic explosion, when it seems that the theoreticians would prefer a “BIG INFLATE” kind if idea.
Here is my “BIG CHILI” metaphor: make a pot of chili, real thick chili with lots meat and onions, peppers, celery and black beans. Bring it all to a boil; now watch the bubbles that come to the top and burst, that is a model of our universe; all the matter (and everything else) in our universe rides on the outer membrane of the bubble. But the bubble forms out of the underlying soup.
“wait till you see what the beans do”

While I agree that the coordinates are probably (0,0,0) (or (0,0,0,0)?), just where is that?

It seems that if one was riding some inflating surface, like we are real small ants on the surface of an expanding balloon, we'd be able to deduce where the balloon is being inflated from?


But if the universe is all there is, where did the pot, chili, meat, onions, peppers, celery, black beans, and the heat source come from?

[American]

What's north of the north pole?

Anyway, when I took Stars and Galaxies, they taught the Big Bang by describing the moments just after the event, moving backward toward that first "moment" in fractions of a second. They covered around 6 or 7 different states of the universe through its infancy over 5 hours of lecture, roughly.

A lot has changed since the 1920s, so I don't know if they still teach it that way.

[kedo1981]

Like the bubble in a pot of chili the universe bubble is a natural effect of the “viscosity” of the “chili” and some amount of “energy”.
Where did the chili come from what is it made of, Hawking calls it “space time liquid” but is quick to point out that it’s only a theoretical construct.
Maybe it’s Gods’ Chili pot

[Zombified]

The location of the explosion was, roughly speaking, "everywhere".

It wasn't just matter and energy exploding, space-time itself was expanding from a very small point or region. Since then, the universe has been expanding at an ever-slowing rate.

The ants riding on the expanding balloon is a pretty good analogy, I'd heard something similar somewhere before. Imagine you take an uninflated balloon, and you take a magic marker and mark a bunch of spots on it. Then you start to inflate the balloon up to a large size. None of the spots you drew is in the "center" of the expansion; they all started out equally close the center, and they are all getting equally far away from each other. Furthermore, all of them are "staying in place" on the balloon, they aren't really moving even though they're getting farther apart. The spots (or ants) on the balloon are in a two-dimensional world, and as far as they can tell the universe is a sheet which just keeps getting more and more stretched, and no one point is more obviously the center than any other.

That is what's happening with the galaxies in the universe; they recede from each other because the space between them is getting larger, not because they are moving.

Whether or not this "bubble of space-time" is embedded is some larger structure is at this point a matter of conjecture.

For once, that makes quite a lot of since.

From my logic, asking what was the begining of the universe is like asking when is the end of time. There really is none, they just go on forever in either direction.
But I'm not so sure on that now.

[Jon_in_london]

I think the question is quite similar to asking 'what happened before time began. There was no before time began because time hadnt been invented yet. Hardly a satisfactory answer though and prolly why the big bang seems so obscure a theory that few are really happy with.

[Hazelip]

What was the original particle? Hell, I don't know. I don't care much, either.

Why should I?

Originally posted by Ma'at
I would ask pi but as she is currently studying I won't disturb her much as she would love me too, but I think she said the big bang started when nothing exploded, and the universe began. I for one cannot recall accurately what the theory is called or the exact desciption she gave, I will edit it as I find out how wrong I am.

try here (http://www.ppd.clrc.ac.uk/pub/bigbang/part1.html) One site I know pi spends time in alot. you and me is going to have some hissy words, stop showing everybody where I lurk.

That sites the Particle science, version and not the quantam mechanic thingamebob I normally lurk am on. :D lol

Now quit showing me site to all and sundry, or I'll kick you out :p

P_I xx

Hi Dc try these if your interested in what made us other than god

few sites
nasa (http://liftoff.msfc.nasa.gov/academy/universe/b_bang.html)
LaRocco (http://www.umich.edu/~gs265/bigbang.htm)
Hawking (http://www.leaderu.com/real/ri9404/bigbang.html)
my personal favorite discussion at the moment of parrallel universes and possibility of a cross freaky phenomenon over that created ours.
parallel links (http://news.bbc.co.uk/1/hi/sci/tech/1270726.stm)

P_I:D happy reading

My pet topic at the moment.

c/o
http://news.bbc.co.uk/1/hi/sci/tech/506349.stm

By BBC News Online Science Editor Dr David Whitehouse
The Viper microwave telescope situated at the Amundsen-Scott South Pole base has detected ripples in the so-called microwave background radiation - the "echo" from the Big Bang.

Such variations were first detected by the Cosmic Background Explorer satellite (Cobe) in 1992 and are regarded as being of fundamental importance in understanding the birth of galaxies from a featureless young cosmos.

The new observations cast new light on the origin of the so-called "seeds" of the galaxies and provide more evidence that gravity is a more complex force than many believe.

The Viper telescope is situated at one of the best and probably also the worst places on Earth to put a telescope.

Perched on the vast plateau of ice surrounding the South Pole, it boasts atmospheric conditions that make it the best in the world to observe the Universe in millimetre and sub-millimetre wavelengths.

This is because the thin, dry air over Antarctica has the lowest water vapour content of any comparable observatory site. This means that the interference or "noise" created by such water vapour, which is a serious obstacle in astronomical research, is minimised.

Matter and radiation

For over a year, Viper has been observing the cosmic microwave background radiation (CMB) that originated when the Universe was only 300,000 years old.

It was formed when matter and radiation "decoupled". The matter went on to form galaxies and stars. The CMP then just spread out into space - where it still is and can be detected. Some scientists describe it as the "echo" from the Big Bang. The CMB was first observed in 1965.

Tiny fluctuations in the CMB give astronomers information about the distribution of matter in the early Universe - how galaxies and clusters, stars, planets and quasars might have evolved from the "primordial soup" of free-floating protons and electrons.

Without doubt, Viper has seen the ripples in the background radiation with the results to be published in a forthcoming issue of the Astrophysical Journal.

But the ripples cannot be fully explained by a simple idea that the Universe began in a Big Bang some 15 billion years ago and has been expanding ever since with only gravity affecting the expansion.

The best explanation for the observations requires that over large distances gravity becomes a repulsive force, not an attractive one.

It is not a new suggestion and according to some astronomers there is a growing body of evidence to support the idea. But it is not something that many astronomers feel particularly comfortable with at the moment.

P_I:D

[diddidit]

Originally posted by Whodini

If we can detect the background radiation, and have these expansionary models, etc., can't we locate where the Big Bang started, where everything is explanding from?


No, you can't - finding the center of the expansion of the universe would require being able to perceive a fourth spatial dimension, if I've got my head wrapped around this reasonably correctly.

As an analogue, consider an inflating balloon. The surface of the balloon is the universe; inhabitants of that universe can see the galaxies in the distance receding, but because their perception is limited to two dimensions they cannot see that the center of the expansion is in the third dimension - the center of the balloon.

Perhaps The Bad Astronomer might make an appearance and tell me if I'm mostly right, or if I should stick to designing filing cabinets...

did

[Frostbite]

Correct me if I'm wrong, because I'm uneducated and just guessing.

If, at the Big Bang, all of the Universe is condensed into an infinitely dense point, then that would prove that there is an infinity of matter in the Universe, and that Time itself would completely stop. Right? But I think we can venture a guess that the Universe is very much finite, and we could be able to measure accurately the size and mass of the Universe. So in that sense, if all matter in the Universe is condensed into one point, then isn't it impossible that Time is completely stopped? Time would surely slow down to an almost infinitely slow pace, but it would still be going forward until the next Big Bang, as a cycle. Therefore, would it be possible that the Universe never began in the first place, and will never end?

I'm just tired of hearing about this point where supposedly everything started. Can anyone show where this Point is?

:)

[shanek]

Originally posted by Whodini
I'm just tired of hearing about this point where supposedly everything started. Can anyone show where this Point is?

:)

Sure. Point in a direction that is at right angles to length, width, and height and you'll be pointing straight at it. :p

Originally posted by Frostbite
Correct me if I'm wrong, because I'm uneducated and just guessing.

That's never a good thing. There's lots of information out there; you don't need to guess.

If, at the Big Bang, all of the Universe is condensed into an infinitely dense point, then that would prove that there is an infinity of matter in the Universe, and that Time itself would completely stop. Right?

Well, no. I don't quite follow this syllogism. Regardless, the infinitely dense point you're talking about is called a singularity. This is essentially a mathematical anomaly that astrophysicists have been trying to work around for years.

But I think we can venture a guess that the Universe is very much finite, and we could be able to measure accurately the size and mass of the Universe.

Remember that the universe has a speed limit -- c, the speed of light. Because of this, there are some parts of the universe that we will never see. There is very little doubt that the universe is finite, but we will never be able to 'measure' it, in that sense.

What we can measure, however, is the energy density of the universe, but this is an estimation at best.

So in that sense, if all matter in the Universe is condensed into one point, then isn't it impossible that Time is completely stopped? Time would surely slow down to an almost infinitely slow pace, but it would still be going forward until the next Big Bang, as a cycle. Therefore, would it be possible that the Universe never began in the first place, and will never end?

Waoh, slow down. The beginning of the universe was probably the Hawking-Turok instanton (I'm a believer, anyway). With this model, the singularity is virtually eliminated, and there is no moment where t = 0. Further, the Big Crunch hypothesis is all but dead, because the galaxies are accelerating away from each other. The large-scale geometry of the universe -- open, flat, or closed -- is no longer considered an absolute indicator of the universe's ultimate fate.

But you must consider that time is still abstract and relative. Even with all of that matter in one place, time is only slowed according to an observer in another inertial frame. With the entire universe, space and all, crammed into a single point, there are no other inertial frames and besides that, the laws of physics are pretty meaningless. This is why scientists don't like singularities.

Just know that it's a pretty sure thing that our universe is not part of some infinite cycle or "multiverse". It began a finite amount of time ago and it will likely exist for an eternity. There is no evidence, observational or mathematical, for any larger system.

Originally posted by Passionate_Iniquity
you and me is going to have some hissy words, stop showing everybody where I lurk.

That sites the Particle science, version and not the quantam mechanic thingamebob I normally lurk am on. :D lol

Now quit showing me site to all and sundry, or I'll kick you out :p

P_I xx You love me really, and you wouldn't. Would you? :D I did not show them all your sites yor lurk argue obliterate in a flurry of lace,leather and talons, so get your claws out of the drawers ;)

Originally posted by shanek


Sure. Point in a direction that is at right angles to length, width, and height and you'll be pointing straight at it. :p

That's what I expounded too, the last time this subject came up, but I was shot down by the more astrophysically competent around here; I was told that four dimensions weren't required, all was explainable in terms of three dimensions, just as you can do the math for the curved surface of a sphere without bringing the third dimension into it.

I get that it's a more "point all around you" situation, since we are still inside that point; it's just a lot bigger now.

Beats me, I'm no physicist.

[gnome]

(resisting the urge to whip out the accordion)

:D

[Graham]

Originally posted by Whodini
I'm just tired of hearing about this point where supposedly everything started. Can anyone show where this Point is?

:)

As I understand it that point grew and grew and grew (much like the enormous turnip) and is now everywhere (unlike the enormous turnip which I believe they eventually cut up and ate).

Anyway, you can't now isolate the point from the rest of the universe because the point .is the rest of the universe.

Does that make sense? :confused:

The biggest problem with any kind of visualization is that people keep calling it a point. It was not a point.

This infinitely small piece of space magically appeared, then expanded.

I don't have trouble with the expanded part.

Originally posted by Whodini
This infinitely small piece of space magically appeared, then expanded.

I don't have trouble with the expanded part.

Again, it's misleading to say that something "appeared", because that would imply that there was nothing there before. It must be understood that there was no before.

The universe has always existed, by definition. Too, according to the model that I favor, there is no t = 0, because of quantum uncertainty. Time and space stem from each other. Supposedly, the math makes it pretty clear, but it's nonetheless nearly impossible to describe the origin of the universe when people keep making references to inflating balloons and such, because it is then assumed that the 'uninflated' balloon is a point with the mass of the universe. This is not the case.

[Soapy Sam]

In the Next Universe Up, there was a washing machine, where God washed His socks. In the back of this machine was a black hole. One day , a holy sock , (sorry), disappeared, as they do, down this hole and appeared here, in our universe. But the universe wasn't there yet, because of delays in delivery of materials.
Anyway, the sock dropped out of a white hole and then expanded until what used to be the sock is now the OUTSIDE surface of the universe. We are somewhere near where the big toe used to be about 20 billion years ago.

This model makes it clear that the point where it all started is now smeared over a spacetime surface the size&age of the universe. It also explains why everything smells so bad. Life evolved from divine athlete's foot and everything else is caused by loose threads.

Next question.

Well, heck it's no crazier than some stuff supposedly respectable scientists believe. And it explains one of the great unsolved mysteries- where fluff comes from.

[Stimpson J. Cat]

Soapy Sam,

So does this mean that quantum foam is really laundry detergent?

Dr. Stupid

You say


----
there was no before
----


Then you say


----
The universe has always existed,
----


What is this "always" then?

Originally posted by Whodini
What is this "always" then?

t = 0

This is, conventionally, the 'beginning' of time.

In saying "always", I mean there are no values of t that are less than 0, thus there is no "before". For as long as time has existed, the universe has existed. It follows that the universe has always existed.

[Soapy Sam]

Stimpy- Nail that copyright now! Quanto-the wonder wash! (Of course it's only good for rubber sheets). Actually , now I have a Creation Miff, I may start my own religion. For 50 bucks, you can be a Bishop.

This is my brain ->O
This is my brain on 48 hours without sleep, 3 air flights, 4 time zones and a 12 hour shift in one day -> . <-

It's now midnight in Scotland and if I go to bed now I may wake up in synch with the rest of the country. I only logged on to stay awake and look for Paul's link to the folding@home thing, which I've lost. Manyana!

[Always Free]

I deleted all the crap I just posted and found this:

http://www.bbc.co.uk/science/horizon/2001/parallelunitrans.shtml

It gives a transcript to a program about parallel universes and the 'big bang'. You have to read it!!:D

[AmateurScientist]

Originally posted by Thr0n


Again, it's misleading to say that something "appeared", because that would imply that there was nothing there before. It must be understood that there was no before.

The universe has always existed, by definition. Too, according to the model that I favor, there is no t = 0, because of quantum uncertainty. Time and space stem from each other. Supposedly, the math makes it pretty clear, but it's nonetheless nearly impossible to describe the origin of the universe when people keep making references to inflating balloons and such, because it is then assumed that the 'uninflated' balloon is a point with the mass of the universe. This is not the case.

Did someone ask for my opinion? Oh well, I'll give it anyway. This is correct.

AS

Originally posted by Always Free
I deleted all the crap I just posted and found this:

http://www.bbc.co.uk/science/horizon/2001/parallelunitrans.shtml

It gives a transcript to a program about parallel universes and the 'big bang'. You have to read it!!:D

NOOOOooooooooo....!!

This is extremely deep theory physics. Guth and Kaku are good at heart, but they unintentionally mislead the public into thinking that this is real physics (especially Kaku). Go to any bookstore and you will find volumes of books on 'Hyperspace' and 'Wormholes'. You will rarely find anything on basic mechanics, or hell, even basic astrophysics. People get the idea that string theory is the only way physics can advance at this point, and that is not the case. It is only favored because there is a severe lack of funding in the area of research.

Please, consider that almost nothing they say can be backed up with evidence. It's just abstract math. The universe they live in comes in a variety of tasty, but unecessary and likely nonexistent, extra dimensions.

I'm really surprised they have Turok commenting on the multiverse theory as if it has any truth to it. I suspect they may have taken some of his comments out of context, since he was never a proponent of this view (as far as I know) -- his model eliminated the need for a preexisting medium.

I'm not going to claim that string theory is utter nonsense, but at this point, I think there is much more important work to be done with high-energy and condensed matter physics.

[garys_2k]

Perhaps it would help to think of time like measuring the latitude on the earth. Presumably, none of us have any problem with the north pole being the most northerly point in existence. Same with the "beginning" of time. Pretend time is measured as the distance from the north pole, where the start is the most northern point. You can go back that far (OK, you can approach that point, maybe not quite get there, but that's a quibble for this analogy), but not any farther, just like you can't go farther north than the north pole.

I think Hawkings suggested this analogy in Nutshell, but I may be wrong. In any case, it's helped me put things in a better perspective.

[dsm]

Originally posted by Whodini
What are the coordinates where the Big Bang took place?

If the coordinates are represented by (x, y, z, t) where (x, y, z) is a three dimensional coordinate and t is time, then the coordinate is (x, y, z, t) where x, y, z, and t have any value.

Did that make sense? :confused:

:D

----
If the coordinates are represented by (x, y, z, t) where (x, y, z) is a three dimensional coordinate and t is time, then the coordinate is (x, y, z, t) where x, y, z, and t have any value.
----


How can it originate from a single point if x, y, z, and t can take on any value?

[dsm]

Originally posted by Whodini
How can it originate from a single point if x, y, z, and t can take on any value?

Because every value of (x,y,z) was contained within the Big Bang at t=0. No new values of (x,y,z) have been created by the Big Bang -- everything just expanded. Therefore, as t increases, so does the original point of the Big Bang.

Ultimately, we are still inside the point. :eek:

----
Because every value of (x,y,z) was contained within the Big Bang at t=0. No new values of (x,y,z) have been created by the Big Bang -- everything just expanded. Therefore, as t increases, so does the original point of the Big Bang.

Ultimately, we are still inside the point.
----


You say "inside". What is outside?

And everything that I know that expands, has some other force making it expand.

[dsm]

Originally posted by Whodini

You say "inside". What is outside?


Unknown. You'd probably have to add another dimension to represent it if it exists. Since we are three dimensional beings (plus time), it's probably not something we will ever be able to move thru.


And everything that I know that expands, has some other force making it expand.


Inertia? The infusion of energy as a result of the Big Bang put the Universe into the motion of expansion. Since a body in motion stays in motion unless acted upon by something else, the Universe continues to expand. Since gravity is the only thing that will slow that expansion, the question is whether there is enough gravitational bodies in the Universe to cause the expansion to stop and reverse.

Now, as to where the initial infusion of energy came from to kick off the Big Bang, I think they're still working on that. Maybe it was... God?

:eek:

[rwald]

Thr0n, can you go on more about this Hawking-Turok instanton? I've always been interested in cosmogony, but personally dislike both the "something came out of nothing" idea (smacks too much of God) and the "universe has existed since t= -infinity" idea (it's turtles all the way down...). I heard there was some alternative to either of these, and it sounds like you know it. Could you enlighten us? (beyond the degree to which you have already done so)

PS: I like string theory :(. That said, I know that the background-dependence thing is a major problem the theory needs to deal with; maybe M-theory will solve that. Have you read Lee Smolin's book "Three Roads to Quantum Gravity"? I get the impression that you're the type of person who has already read this, and has specific objections to it, but I'd be interested in hearing your opinion.

[ntech]

Possibly Flatulence from another dimension.

Originally posted by ntech
Possibly Flatulence from another dimension.

The whole world started when someone/thing farted?

[garys_2k]

Originally posted by Whodini


The whole world started when someone/thing farted?
Works for me!

[rwald]

That would explain a lot...

[Frostbite]

Originally posted by Always Free
I deleted all the crap I just posted and found this:

http://www.bbc.co.uk/science/horizon/2001/parallelunitrans.shtml

It gives a transcript to a program about parallel universes and the 'big bang'. You have to read it!!:D

Very cool link, easy to understand for a knucklehead like me.

[ntech]

Originally posted by Whodini


The whole world started when someone/thing farted?

Well it was sort of the description in "Three Roads To Quantum Gravity". But yeah. Another dimension possibly did.

P*sses off theists as well, who think we are special.

[rwald]

Well, the problem with the "our universe is just a quantum fluxuation in another universe" theory is that, in the end, it's turtles all the way down.

I've heard theories that somehow, one universe "was its own parent" and spawned itself, but that doesn't make much sense.

I'm holding out for a theory that says, at times very near t=0, time didn't have any meaning, so asking what happened "before" this is meaningless. I'm not just asking that all t<0 be discounted, but that, for all times between t=0 and t=epsilon, the value of t become meaningless.

[dsm]

But then you run into the "what's on the other side of the epsilon wall?" questions...

:p

[rwald]

Well, the idea is, that when you get past epsilon, you can describe what happened, it just is that time didn't matter. So, it can be described, but you can't go back any farther.

I don't think anyone has a complete (or even partial) theory explaining how this could work. I read this somewhere as a suggestion for an alternative line of research. I only like it because it isn't the "something from nothing" or the "universe (multiverse) existed forever" theory.

[ntech]

Originally posted by rwald
Well, the problem with the "our universe is just a quantum fluxuation in another universe" theory is that, in the end, it's turtles all the way down.

I've heard theories that somehow, one universe "was its own parent" and spawned itself, but that doesn't make much sense.

I'm holding out for a theory that says, at times very near t=0, time didn't have any meaning, so asking what happened "before" this is meaningless. I'm not just asking that all t<0 be discounted, but that, for all times between t=0 and t=epsilon, the value of t become meaningless.

rwald,

That would be right from how I understand it as well. Time did not exist before the Big Bang. Time is a product of our motion.

[DrMatt]

Originally posted by Whodini



I don't know.

If we can detect the background radiation, and have these expansionary models, etc., can't we locate where the Big Bang started, where everything is explanding from?

I don't know.

We can see that everything is getting farther apart.

Space, per se, is remarkably symmetrical. If you take your really big and massive rocket and coast past an asteroid at, say, 15 kph, your path and the asteroids path will both be disturbed due to mutual gravitation. The disturbance will work out the same as if your rocket were "standing still" and the asteroid coasted past you at 15 kph-- or, as if you coasted at 7 kph past the asteroid when it was coasting towards you at 8 kph. In fact, in space, there's absolutely no way to tell the difference between the three scenarios--there's no observation or measurement you could make involving your ship--and things on it--and the asteroid--and things on it--which would tell you which scenario you've got. Which one is moving? which one is stationary?

Measurements are accomplished by comparing objects with other objects. In the case of the universe as a whole, we have no other objects to compare it with. We can't even assign coordinates to "places in space" without parameterizing them with "relative to the earth at the moment when light from a nuclear clock reading 8:58 pm in New Jersey crossed this location".

Testing.

I always wonder...

Does the Big Bang Theory (tm) say that

1. the Big Bang started all of the universe, like the whole damn thing?

or

2. just that it started the local part of our universe, like it is one of many big bangs?


?

[Hellbound]

Whodini:

Both have been proposed at one time or another.

However, the only thing that's on fairly solid ground is that the Big Bang developed into all of the universe that we can know/see/examine/interact with. The inflationary model does allow some possbility for localized expansions that seperate it into "bubbles", but because of the speed of light limit we can't interact with or see anything outside or bubble, so it is not reasonable or scientific to say there were many. Likewise, we can't say there weren't. Again, because of certain limits (mainly a singularity at the Big Bang), we really can't say what came before. It's something like a hunter tracking an animal's trail back to it's den. He may backtrack for 10 miles down the trail, but then the trail has been erased (due to rain, wind, whatever, not important for this analogy). He thinks he's in the right area, but there's no way to be certain because there's a definite, physical block (in the analogy, the lack of a trail. In the universe, the singularity and the speed of light limit) that limits possible knowledge.

So, to answer your question, it's both. The Big bang started all of the universe we will ever know (unless it turns out that the speed of light limit is not set in stone), and no one can say whether or not there were other Big Bangs.

[Cecil]

I see one problem with the balloon model of the expanding universe, namely, that it implies that there is a "center" of the universe, but we can't go to it.

Here's a two-dimensional approximation of what I think is a better analogy.
Take a circular rubber sheet, or if you prefer, an infinitely ductile bounded plane. Compress it down to a point, then mark the point with a dot. As you stretch the sheet out, you notice that the "centre" of the universe is in fact everywhere. Regardless of you point of view, you are always standing on the center of the universe.

----
Take a circular rubber sheet, or if you prefer, an infinitely ductile bounded plane.
----


Hold on, where did this sheet or plane come from?

[rwald]

We've been through this. There are three theories:

It came into existence from nothing. Personally, I find this explanation dissatisfying, but according to some theories, gravity should be counted as "negative energy," meaning that the total energy of the universe is zero; so, it's not that something came from nothing, but that nothing changed forms.

It came from a different universe. This includes theories that singularities in black holes are new universes, or that certain quantum events can cause the spawning of a new universe. I don't like this one either, because it just moves the question into a different universe. One variant on this theory states that a previous universe ended with a Big Crunch, and that the mass-energy from that resulted in our Big Bang. Again, I don't like that theory. It's turtles all the way down.

Perhaps, at times near t=0, time had no meaning. It's hard to explain what this is talking about, but if you look at time as only the connection of causes with effects, and the ordering of "events" in a sequence of what events could influence others, it's somewhat conceivable that these connections didn't exist in the nascent universe, thereby making the understanding of time meaningless. This is still a fresh theory, so work is being done on whether it makes any sense physically.

Whichever of these is true, for all practical purposes we will never know which it is. For example, if the universe was spawned by another universe, we could never tell, because we could never see that universe. So, while these are the current theories on the subject, I'm not so sure we'll even answer the question to your satisfaction.

[sorgoth]

I understand how you're explaning that there WAS no before, but the matter HAD to come from somewhere. Unless you want me to believe it just magically appeared.

[rwald]

Are you asking me? According to the third theory I mentioned, "before" doesn't make sense in the context of the earliest parts of the universe. It's kinda a complicated idea, so I don't blame you if you don't get it. But what I'm saying is, that time didn't exist before a given time, so asking what happened "before" that time doesn't make sense.

Wait...I'm asking for space to exist before time, but how that could work with relativity...I'll need to think about it...

----
"before" doesn't make sense in the context of the earliest parts of the universe.
----


Sounds like you are saying "I can't explain it, therefore I'll say that before doesn't make sense."

[rwald]

I told you, because time has no meaning doesn't mean we can't explain what could have happened. Perhaps the link between cause and effect (which characterizes time) didn't exist. There. You can understand that process, but it prevents you from asking what "caused" the universe.

[garys_2k]

The moment of the big bang is like the north pole -- the beginning. To ask what "was" before that is to ask what is north of the north pole, both are meaningless questions.

[RichardR]

Originally posted by garys_2k
The moment of the big bang is like the north pole -- the beginning. To ask what "was" before that is to ask what is north of the north pole, both are meaningless questions. Surely there is plenty that is north of the north pole. The North Star, for example (if you keep going).

Originally posted by garys_2k
The moment of the big bang is like the north pole -- the beginning. To ask what "was" before that is to ask what is north of the north pole, both are meaningless questions.


So you don't know what happened, therefore you invent some analogy to say that it is a meaningless question!

[dsm]

Originally posted by Whodini
So you don't know what happened, therefore you invent some analogy to say that it is a meaningless question!

Is the answer to any number divided by zero also invented?

Originally posted by dsm

Is the answer to any number divided by zero also invented?


Speaking about math is hardly speaking about the real world.

[ntech]

Originally posted by Whodini



Speaking about math is hardly speaking about the real world.

Well, I don’t know about that. I’m glad that the architects who designed the tunnels, bridges and buildings knew their math.

Math is critical to designing safe products and structures. Seems quite real to me.

Without math there would be no computers either. They seem real to me as well.

[gnome]

Originally posted by Whodini



So you don't know what happened, therefore you invent some analogy to say that it is a meaningless question!

I would characterize it as inventing an analogy to explain how it might be a meaningless question.

----
Well, I don’t know about that. I’m glad that the architects who designed the tunnels, bridges and buildings knew their math.

Math is critical to designing safe products and structures. Seems quite real to me.

Without math there would be no computers either. They seem real to me as well.
----


Well math describes parts of the real world, but there is no number 1 floating about in space, etc. You will not be walking in a park and suddenly encounter f(x) = e^x*sin(x) just sitting there.

It is interesting that

Math--D-->Real world, or that

The not real--D-->The very real

where --D--> means "describes very well".

[ntech]

Originally posted by Whodini
----
Well math describes parts of the real world, but there is no number 1 floating about in space, etc. You will not be walking in a park and suddenly encounter f(x) = e^x*sin(x) just sitting there.

It is interesting that

Math--D-->Real world, or that

The not real--D-->The very real

where --D--> means "describes very well".



Huhhh? :rolleyes:

[dsm]

Originally posted by Whodini
Speaking about math is hardly speaking about the real world.

Math is a model of the real world.

Point was, the closer you get to t=0, the closer you are to looking at something that is "undefined" (like N/0). Since all "things" in our Universe must have a positive t component, then something at t=0 is undefined (and, because of the wall at t=0, trying to talk about t<0 is probably equally meaningless).

After all, how could you talk about something that, by definition, never existed?

----
Point was, the closer you get to t=0,
----


My point, stated rather poorly by me originally, is that just because there was/is a Big Bang, that doesn't mean that there is a t = 0, so it still could be meaningful to talk about what happened before the Big Bang, especially if our Big Bang was a local one and not The Big Bang.

[jj]

Originally posted by Whodini
----
You will not be walking in a park and suddenly encounter f(x) = e^x*sin(x) just sitting there.



Since it has infinite energy at infinite time, I certainly hope you never find that just sitting there. If you do, you've answered the question to where the big bang came from all by yourself.

On the other hand, Euler did wander onto e^(i*pi)+1=0 in a forest, didn't he?

[dsm]

Originally posted by Whodini
My point, stated rather poorly by me originally, is that just because there was/is a Big Bang, that doesn't mean that there is a t = 0, so it still could be meaningful to talk about what happened before the Big Bang, especially if our Big Bang was a local one and not The Big Bang.

When you begin talking about a "local" bang, you then run into rwald's turtle. The next question is "where did the stuff come from that started all these local bangs?" Well, it was probably some leftovers from the Big Bang that went crunch. Eventually, you get back to t=0 and The Big Bang.

[rwald]

Whodini, I'm sure you're not going to answer this, but I'll ask anyway: How do you think the universe started? If you don't like our theories, what are yours?

[dsm]

Originally posted by RichardR
Surely there is plenty that is north of the north pole. The North Star, for example (if you keep going).

No, not really. Assuming the North Star is directly over the North Pole, then, to get to the North Star from the North Pole, you would go "up" and not "north".

:D

Originally posted by rwald
Whodini, I'm sure you're not going to answer this, but I'll ask anyway: How do you think the universe started? If you don't like our theories, what are yours?


I'm not sure.

But if pressed I'd probably say the universe wasn't started/created, it just always was.

[Zombified]

Well, the evidence is pretty clear that the universe is expanding and was formerly much hotter. We know this because of the redshift of deepsky objects and how that is correlated with other measurements of distance, microwave background radiation, and so on.

Do you believe this evidence has been misinterpreted, or are you postulating a cyclical universe? Why do you suspect the universe did not have a beginning?

----
Well, the evidence is pretty clear that the universe is expanding and was formerly much hotter.
----


I agree with that. I've done some research on statistical theory of estimating Hubble's constant, so I am somewhat familiar with some of the cosmological theory by osmosis.

However, when one has a theory, and that theory goes as far back as X, one can always ask

'What happened before X? How did X start?'

To me, and this is my belief, it is more aesthetic and more natural to say that the universe always was, and that the Big Bang could be one of many, but probably is not The Big Bang (ie. the thing that started the universe).

The Big Bang is a great theory, but in my opinion, it describes the expansion, not the origin.

[garys_2k]

Originally posted by dsm


No, not really. Assuming the North Star is directly over the North Pole, then, to get to the North Star from the North Pole, you would go "up" and not "north".

:D
EXACTLY!

Nothing is "north" of the north pole, but we don't have a problem with the concept of "more north" or "south." All it takes is acceptance of a spherical reference system, where the underlying system (a sphere) has no boundaries and we have to select arbitrary starting and ending points for our system.

I believe time works the same way. Virtually be definition, the moment of the big bang is the temporal "north pole." We have been moving in a southerly direction ever since, and the only question left is whether the universe will curve back onto itself, be more or less spherical and end at the opposite "pole" in a big crunch, or if it is more open, and unbounded at the other end.

Why does time have to be thought of in a linear reference system, with an infinite, unbounded "before" and "after?" I see nothing in physics that requires that worldview.

[dsm]

Originally posted by garys_2k
Why does time have to be thought of in a linear reference system, with an infinite, unbounded "before" and "after?" I see nothing in physics that requires that worldview.

Mathematically, time is a coordinate in dimensional space. Therefore, it is represented by a number which automatically makes it a linear reference system.

You could reverse time, but that merely changes where "before" and "after" are. Going "sideways" in time doesn't make sense as either you're just moving to a different 3-D coordinate or you're moving to another (ie. fifth) dimension.

Doesn't Newton's theories lead to the "linear time" worldview? Things like "cause and effect", "action and reaction", etc.?

[rwald]

And that's where Einstein and quantum physics came in.

[garys_2k]

Originally posted by dsm


Mathematically, time is a coordinate in dimensional space. Therefore, it is represented by a number which automatically makes it a linear reference system.

No, just because its a coordinate in a space-time system does NOT imply its adherence to a Cartesian coordinate system. There are all sorts of very mathematically valid coordinate systems, the latitude/longitude system for a sphere is the example I gave but there are others.

The problem I see a lot of people here is that they are trying to force time-space to an infinite, unbounded Cartesian system where every line is n-dimensionally "straight" and never converges. There is no need for the universe, or space-time in general, to have to fit such a coordinate system.

Mathematically, what we know about space-time is much more consistent with a non-Cartesian coordinate system, so why not use that as a basis for discussing it? In that system it is easy to discuss an absolute beginning of time, analagous to a north pole. Just as lines of latitude and longitude are always orthogonal to each other, the spatial dimensions are likewise always locally-orthogonal to time, but (again) that may not be true over the larger view.

You could reverse time, but that merely changes where "before" and "after" are. Going "sideways" in time doesn't make sense as either you're just moving to a different 3-D coordinate or you're moving to another (ie. fifth) dimension.

You can go "north" or "south" on the earth by following lines of longitude, so if we just call north "earlier" and south "later," it is entirely consistent to move in time. We always seem to travel through time from north to south, however, but the analogy (and the application of a non-Cartesian reference system) has nothing to do with that.

Moving "sideways" on this spherical frame of reference (as applied to our universe) only means that you are moving through space. If you will, travelling west or east on this system may be thought of as moving left or right (or up/down, back/forth). You cannnot move "sideways" through the time dimension any more than you can move sideways along a line of longitude WITHOUT moving along a line of latitude (assuming you don't leave the earth's surface).

The only limit to picturing time-space this way is that the earth analogy only gives us two dimensions (north/south & east/west) to use to apply to a four-dimensional problem. We can't illustrate moving in all four directions, before/after, front/back, left/right and up/down on a three dimensional sphere, but its fine for illustrating how a couple of the dimensions can work together. The "real" universe seems to be spherical, but in all four dimensions, with analagous measurements to latitude and longitude.

Doesn't Newton's theories lead to the "linear time" worldview? Things like "cause and effect", "action and reaction", etc.?
Newton's work speaks nothing about excluding a spherical reference frame, only that things are locally orthogonal. Since anywhere "far enough" from the poles would see their lines of latitude and longitude lying at ninety degrees, they would have no problem measuring with right angles. My house's property lines were surveyed with as good a set of right angles as the surveyor could use, but I know that the 120' east-west line to the north probably SHOULD be very infintesimally shorter than the one 90' to the south. The surveyor knew that, I'm sure, too. But within the limits of measurement and the approximation of his equipment, these locally orthogonal measurements do just fine.

Thinking of the big bang in a spherical coordinate system makes a lot more sense than some kind of never-ending Cartesian one. Problems of the "beginning" of space-time are trivially easy to picture.

[rwald]

Gary, while I agree with you in principle, I was pretty sure the universe appeared to be closer to a hyperbolic system than a spherical one. What do you say to that?

[dsm]

Originally posted by garys_2k

No, just because its a coordinate in a space-time system does NOT imply its adherence to a Cartesian coordinate system. There are all sorts of very mathematically valid coordinate systems, the latitude/longitude system for a sphere is the example I gave but there are others.
[/b]

I was merely saying that the time component in 4 dimensions is linear (or can you show that time itself is accellerating or decellerating?). How you measure the other 3 components is a separate issue. Latitude/longitude is a 2 dimensional measurement -- you still need the radius from a center point to complete the 3 dimensions.


Moving "sideways" on this spherical frame of reference (as applied to our universe) only means that you are moving through space.


I see two possible definitions for moving "sideways in time":


In 4-D space represented by (x,y,z,t) [or if you prefer (lat, long, rad, t)], holding t constant, but changing one or more of the other 3 values.
In 5-D space, holding the first 4 dimensions constant while changing the fifth (ie. interdimensional travel).


I don't see #1 as anything special while #2 is quite special.


The "real" universe seems to be spherical, but in all four dimensions, with analagous measurements to latitude and longitude.


Represented mathematically by (latitude, longitude, radius, time), correct?

[garys_2k]

Originally posted by rwald
Gary, while I agree with you in principle, I was pretty sure the universe appeared to be closer to a hyperbolic system than a spherical one. What do you say to that?
Probably very true.

I used the spherical shape to extend from the earth's latitude/longitude analogy, but there's nothing limiting it to that. In fact, depending on whether they ever settle on space's apparant expansion rate the actual shape is still up for speculation. Closed or open, hyperbolic, parabolic, saddle shaped, or something else -- but Cartesian is probably the least likely.

[garys_2k]

Originally posted by dsm


I was merely saying that the time component in 4 dimensions is linear (or can you show that time itself is accelerating or decelerating?). How you measure the other 3 components is a separate issue. Latitude/longitude is a 2 dimensional measurement -- you still need the radius from a center point to complete the 3 dimensions.

There's nothing special about time -- its just another dimension. It has no need to run in "the background," separate from spatial dimensions, so whatever reference system works well for space (and it would appear that some kind of non-Cartesian, closed on at least one end does for now), it can work equally well for time.

Since we seem to have the start of the universe at a time-space singularity, then I'm for considering all dimensions as originating like the north pole is the "originator" of the dimension "north/south."


I see two possible definitions for moving "sideways in time":


In 4-D space represented by (x,y,z,t) [or if you prefer (lat, long, rad, t)], holding t constant, but changing one or more of the other 3 values.
In 5-D space, holding the first 4 dimensions constant while changing the fifth (ie. interdimensional travel).


I don't see #1 as anything special while #2 is quite special.


Agreed on number two, but I think number one is excluded by the space-time equivalence and one's inability to travel at infinite speeds. ANY displacement in a pure spatial direction must involve movement forward in time, unless we're talking some VERY special, specific cases. In other words, our "reality cones" extend through space and time, in any direction in space but only outward in time.


Represented mathematically by (latitude, longitude, radius, time), correct?
OK, now for OUR real world, yes, but that's getting away from the analogy I built.

The "beginning of time is the same as the north pole" analogy works best for one dimensional creatures living on a circular line, like a loop, wrapped around a sphere. The circle is traveling south, always parallel to longitude lines, getting larger as it goes. Further, the circle began as a point at the north pole and has been moving evenly south ever since.

Note: The real underlying surface may not be a sphere, another shape could work just fine, but I'll stick to this for my geography-centric terms, they're easier for me to use.

The creatures occupying this line see their circle world getting larger all the time, their universe is expanding. They know only two dimensions, clockwise/counterclockwise (to them, maybe front/back) and earlier/later. If they can envision a sphere world (as we know it), then they can easily see how both their space started growing from a point at their big bang and how time also started from that same origin, "at" the pole.

[rwald]

And the nicest thing about the sphere analogy is that it has no messy singularity.

[dsm]

Originally posted by rwald
And the nicest thing about the sphere analogy is that it has no messy singularity.

Why? Maybe I'm just not getting my head around the implications of a 4 dimensional sphere yet...

[rwald]

Forget about a four-dimensional sphere. Look just at a 2-dimensional sphere (with just latitude and longitude, no altitude), and at the example given by Gary. To the inhabitants of "circle world," their two dimensions, earlier/later and clockwise/counterclockwise, appear to be unrelated, and they ponder how either of them could have begun without a singularity. But when you look at their universe, and look at their world-sphere, you see that there is no singularity at the "north pole." Time and space merge into one another flawlessly, without any unusual hole or bump.

So, it is possible that a four-dimensional shape may represent our universe, and therefore the origin of space and time isn't a problem, but is a simple product of the model. Of course, the shape of the four-dimensional universe will probably not be a sphere; it would more likely be some convoluted structure which you would have trouble picturing anyway (because it may need to exist in the fifth dimension, making it even harder to ponder).

[Soapy Sam]

Whodini said
"... if pressed I'd probably say the universe wasn't started/created, it just always was."


For a certain value of 'always'...

[heath]

Not sure if I'm just adding to the confusion but...

One way to consider time, before, etc with repsect to the universe is to understand that time is an inherent property of the universe and has no meaning outside of it.

For example; you don't ponder how much air a balloon could hold when it was a blob of unprocessed rubber. Air holding is an inherent propery of the balloon not the rubber (if you get my meaning).

The question has no meaning even if it feels like a natural question.

Even better; how fast could we send emails in 2000 BC? The answer is not just ZERO. It's a meaningless question. There was no such thing.

Same goes for time before the big bang.

[ntech]

Very well said, heath.

----
The question has no meaning even if it feels like a natural question.
----


But you're arguing by analogy and in the end just assuming that it is meaningless to talk about the time before the Big Bang.

[ntech]

Originally posted by Whodini
----
The question has no meaning even if it feels like a natural question.
----


But you're arguing by analogy and in the end just assuming that it is meaningless to talk about the time before the Big Bang.


Time did not exist before the Big Bang!

How can we reference something that did not exist?

Originally posted by ntech

Time did not exist before the Big Bang!
How can we reference something that did not exist?


You say that the Big Bang is an event such that time did not exist before it, therefore time doesn't exist before it.

You don't know that, you just define it to be that.

There was some explosion, infintely dense, etc., place. So what came before it? It sounds like it magically appeared.

You're basically saying 'don't ask me that! I don't really know, and since I don't know, I'll say there was no before so I don't have to answer your pesky question'.

;)

[ntech]

Originally posted by Whodini



You say that the Big Bang is an event such that time did not exist before it, therefore time doesn't exist before it.

You don't know that, you just define it to be that.

There was some explosion, infintely dense, etc., place. So what came before it? It sounds like it magically appeared.

You're basically saying 'don't ask me that! I don't really know, and since I don't know, I'll say there was no before so I don't have to answer your pesky question'.

;)

No, I'm not. Time is a product of the motion in our universe. Without that motion there would be no time.

A good book to read would be "Three roads to quantum gravity" as well as some books about Einstein's theories.

I don't define it as anything. It is what I understand from years of reading astro-physics and quantum-physics.

----
No, I'm not. Time is a product of the motion in our universe. Without that motion there would be no time.
----


Maybe there was motion before the Big Bang? Who knows.

[ntech]

Originally posted by Whodini
----
No, I'm not. Time is a product of the motion in our universe. Without that motion there would be no time.
----


Maybe there was motion before the Big Bang? Who knows.


Quite possibly, They just don't know yet.

[rwald]

Motion requires something to move. Before the big bang, there was nothing. Nothing to move = no motion = no time. Q.E.D.

Unless you're one of the people who thinks that our universe "banged" out of something else, in which case it's turtles. Which is why I like a third alternative, or something like Gary's sphere analogy.

[ntech]

Originally posted by rwald
Motion requires something to move. Before the big bang, there was nothing. Nothing to move = no motion = no time. Q.E.D.

Unless you're one of the people who thinks that our universe "banged" out of something else, in which case it's turtles. Which is why I like a third alternative, or something like Gary's sphere analogy.

rwald,

It makes most sense to me that there was no time before the Big Bang. If it all exploded from another dimension then there would have been no time before, nor space for that matter.

I was adding the possibility that we could have been a repeat Big Band after a Big Crush. Even then, time would only exist after the expansion anyway.

Which theory makes most sense to you?

[rwald]

Personally, I find neither the "something from nothing" theory (what you're saying) nor the "existed forever" theory satisfying. I'm hoping that quantum physics or some newer field of physics will show that, for very small values of t, the value of t didn't matter. That is to say, during the earliest moments of the universe, causality didn't exist, and therefore it doesn't make sense to ask what "caused" the universe. Of course, this may well be a pipe dream; we'll have to see how research in string theory and quantum loop gravity goes.

[metacristi]

Big Bang- where did the "original particle" come from?


We simply do not have an answer for the moment [no objective knowledge].But we have scientific hypothesis [albeit speculative].It's better than nothing.I prefer Guth's newest hypothesis,a variation of it more exactly, [involving the existence of an infinity of bubbles].See:

http://www.pbs.org/wnet/hawking/mysteries/html/uns_guth_1.html

My reasons are:

1.The hypothesis that universe appeared out of nothing from an alleged quantum fluctuation [based on some intepretations of QM-the alleged a-causality of quantrum phenomena] does not 'hold' water.From 'nothing' cannot appear 'something',in fact even the absolute vacuum is filled with virtual particles in the form of energy.

2.The answer that it is futile to ask what was before Big Bang since time itself appeared in the moment of Big Bang is only an elegant way to avoid the problem.In fact many astronomers became more and more dissatisfied with this answer lately.


3.It is the only naturalistic way [in the scenario that the bubbles do not have exactly the same constants of nature possible in some of them there are no laws] to explain the fine tuning of the constants of nature [compatible with the the 'weak' anthropic principle].
We just happen to be in the universe [from,possible,an infinity] that has the appropriate laws and constants of nature that enabled the apparition of life as we know it.


4.Finally it is compatible with the observed phenomena and does not contradicts string theories or M theories for example.

[rwald]

Personally, I don't like inflationary theories, mainly because I don't understand what would cause an exponential expansion (I'm sure that someone knows; I just haven't learned this yet). I also dislike the weak anthropic principle, because it is inherently unfalsifiable. However, I remain open to the possibility that these are both accurate. Of course, the question remains: where did the false vacuum come from? You see, aside from my aforementioned favorite theory (that causality didn't exist at the beginning of the universe), everything boils down to something-from-nothing or existed-forever (though I can understand your complaint that my theory is just side-stepping the question).

[dsm]

Hmmm. Given the effects that gravity has on space-time, what happens to space-time when gravity is reversed? :confused:

[metacristi]

rwald

Personally, I don't like inflationary theories, mainly because I don't understand what would cause an exponential expansion (I'm sure that someone knows; I just haven't learned this yet)



The inflationary scenario is the only scientific hypothesis that is able to explain the observed phenomena.As far as I know the are models having a mathematical formalism attached,it's not simple metaphysical speculation.That's why the scientific community consider that the inflationary scenario give us objective knowledge,for the moment.Of course by the nature of things it is clear that inflationary theory is less reliable than GR for example,but anyway we have sufficient reason to consider that it gives us provisional 'objective knowledge'.As a description of observed facts [without the need to explain what caused inflation] it is acceptable.

Now can we explain inflation?Yes using the concept of 'false vacuum' as in Guth's [or Linde] hypothesis.For many this seems to be something metaphysical,especially positivists.However science and the scientific method do allow the existence of metaphysical constructs in scientific theories [not mere hypothesis] as much as the theory 'work' for all our practical purposes and is potentially falsifiable.I see no problem with the nature of the 'false vacuum' whatever it's nature.Guth or Linde's hypotheses are scientific that's all that count.
But false vacuum hypothesis is not falsifiable may object some people.Well not exactly.In some models false vacuum is theorized to have different levels of energy so it is potentially falsifiable even if not exactly now.Evolution theory make the prediction that macroevolution happen over long periods of time,difficult to 'probe',still it would be foolish to not consider it at least a hypothesis [but of course it is a theory].

In the 'false vacuum' problem I am open to all acceptable [logical] possibilities even to make later the constatation that God produced the inflationary process or that the 'false vacuum' doesn't exist or at least that it is very improbable to exist [indirectly as in the Michelson-Morley experiment which made the existence of aether improbable].It's science's task to settle the problem from this point on.If it will be forever unable to do that then Linde's or Guth's hypothesis will remain simple hypothesis [albeit scientific],never becoming [provisional] objective knowledge.Anyway their existence is better than nothing.


The main point for allowing [limited] metaphysical constructs in our scientific theories is that science is always provisional anyway and it's main purpose is to be pragmatic,to work for all our current practical purposes.To not allow that is not rational,the hystory of science has many 'teachings' here.
A good example is the atomic hypothesis.There were in the 19-th century many good physicists that were skeptical about the existence of atoms!They taught that the atomic model should be ignored till physicists would be able to measure somehow atoms [even indirectly]!That despite the fact that the hypothesis 'worked' theoretically very well in many domains.Mach is a famous example among physicists,positivists.The french philosopher Augustine Comte is another example.
Still the atomic theory is considered today as giving us 'objective knowledge'.No further comments.

[tcwolf]

Originally posted by Whodini
I'm just tired of hearing about this point where supposedly everything started. Can anyone show where this Point is?

:)

Anyone else think this conversation is being beaten to death?

[rwald]

Well, first of all, I don't like inflationary theory for purely personal reasons (I personally don't understand it); I've heard enough people who know more about this matter than me who agree with it to argue it. I'm just saying that I personally don't like it. Perhaps, some day, I'll see the mathematical formalism, and really understand where it comes from.

Also, anything which is not in theory falsifiable is not scientific. It can be a tentative hypothesis, but if it isn't falsifiable, it can never progress to a theory. However, indirect evidence does count. For example, to use evolution (as you did), even though we can never observe macroevolution, we can look at the fossil record, and say, "Evolutionary theory makes certain predictions about what we should find in the fossil record, and these predictions are confirmed by the fossil record." Same with atomic theory: "We can't directly see atoms, but judging by the way that different substances interact, it indicates that they are composed of small, indivisible particles."

All science can do is create models of reality. But these models should not be composed of metaphysical constructs.

[metacristi]

rwald


Also, anything which is not in theory falsifiable is not scientific. It can be a tentative hypothesis, but if it isn't falsifiable, it can never progress to a theory. However, indirect evidence does count. For example, to use evolution (as you did), even though we can never observe macroevolution, we can look at the fossil record, and say, "Evolutionary theory makes certain predictions about what we should find in the fossil record, and these predictions are confirmed by the fossil record." Same with atomic theory: "We can't directly see atoms, but judging by the way that different substances interact, it indicates that they are composed of small, indivisible particles."



For inflation theory we have sufficient indirect evidence given the predictions it makes,in total accord with current observations:the acceleration of Universe's expansion,the almost flatness of the Universe,the fact that we do not observe any magnetic monopole and so on.As for Guth's and Linde's proposals they can be safely considered scientific hypotheses.First there does exist a mathematical formalism connected with the ontological theoretical construct proposed [false vacuum].The false vacuum decay can be described mathematically being compatible with QM.Secondly it is compatible with the observed reality and is potentially falsifiable as I argued above.To reject the scientific status [mere scientific hypotheses] of these proposals,as positivists do,is not the wisest thing.

[Dub]

Originally posted by Thr0n

Remember that the universe has a speed limit -- c, the speed of light. Because of this, there are some parts of the universe that we will never see. There is very little doubt that the universe is finite, but we will never be able to 'measure' it, in that sense.


c isnt actually the 'ultimate speed limit'. c is the speed of light in a vacum. Light can and does actually travel faster than c. So the ultimate speed limit IS the speed of light, but ISNT c. Sorry to be pedantic, I just read about it in Feynman's QED and thought I let you know. :)

[solmead]

The problem with using a sphere as a model for space time is that you are arbitraly using the north/South for time. Why not use East/West. North/South has a definite beginning and ending (Where you go past the ending on one side and then go from the ending to the beginning on the other side all without changing directions.) East/West has no beginning nor an ending. No matter how far west you go you'll never go east, but you will pass the original point you started at.

Both discribe two different viewpoints of time, North/South - A definite beginning (the big bang) and a definite ending (the heat death of all existance). East/West - Continually cycling universe.

(edited for spelling)

[sorgoth]

Well...I don't have a degree or anything, so I'm not sure...

But couldn't the universe just have always existed? I know it sounds weird, but couldn't there just have ALWAYS been bang, crunch,bang,crunch? I know, the universe is expanding at an accelerating pace. But maybe it'll slow down,for one reason or another. Who knows? Maybe it wasn't 'created', just always been, in one form or another. It's kind of hard to imagine it that way, but...none of the other theories make more sense to me.

[rwald]

metacristi, I'm not saying inflation is a bad theory. I'm sure it has proper support, and realistically speaking, is a relatively good theory describing the evolution of the universe. I'm just saying that I don't like it. I don't like soccer either, and I have no more reason for the later opinion than for the former.

Oh, and the problem with the universe having always existed is that it's turtles all the way down. Someone else want to relate the story, or should I?

[dsm]

Originally posted by rwald

Oh, and the problem with the universe having always existed is that it's turtles all the way down. Someone else want to relate the story, or should I?

Does a "time loop" turtle? ;)

[rwald]

(originally from http://andstuff.org/TurtlesAllTheWayDown)

"Turtles all the way down" refers to a comment made be an old lady attending a talk about cosmology (I think). Afterwards she approached the speaker and explained that the world could not be a globe as it was well known that the world was a disk resting on the backs of four elephants that stood on the back of a giant turtle.

"Ah", said the speaker, "but what does the turtle rest on?"

"Another turtle", she replied.

"But what does that rest on?" he asked.

"You can't get me there sonny", she replied, "After that its turtles, all the way down"

[dsm]

What if the turtle rests on its own back? (Another way of asking "does a time-loop turtle?")

[rwald]

A better answer to this question (from Terry Pratchett's Small Gods):

"It doesn't stand on anything. It's a turtle, for heaven's sake. It swims. That's what turtles are for."

It is turtles all the way down...

Things get strange around t = 0...

[xouper]

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