Did the Universe appear from an infinitely dense, infinitely small point?

[Aethelwulf]

There's a very small amount of room at this point - everything at this singularity experience spacetime appear between each object - as the universe expanded, it cooled enough to allow the dimensions of spacetime as we currently understand it exist.

[Cougar]

To believe in a breakdown of the theory is so far, a personal choice.

Nope. Your concept of "singularity" is incorrect. It means ERROR, you have gone out of bounds. You can be certain that the following professor never taught that "the universe was once an infinitely dense, infinitely small point."

"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." -- Tony Rothman

What does it mean for something to be "infinitely dense"? How do you make meaning out of this? It's meaningless. It's not a matter of personal choice.

[Aethelwulf]

Nope. Your concept of "singularity" is incorrect. It means ERROR, you have gone out of bounds. You can be certain that the following professor never taught that "the universe was once an infinitely dense, infinitely small point."

No I really mean that it is a personal choice. Some of us embrace singularities - I don't embrace all singularities, just this one. I like it, and I know many people that like it also. I understand exactly what a singularity is, please don't partonize me. I meant this really as it sounds - I personally do not see it as a breakdown in theory.

[Shaula]

You have such a point as the origin of the mainstream model the BB.

Doesn't matter how many times you say it - not true. The mainstream BB theory stops short of a point as origin.

[Aethelwulf]

Doesn't matter how many times you say it - not true. The mainstream BB theory stops short of a point as origin.

Well, I've already established with another poster here that essentially we have dealt with BB appearing from a point is in fact what current theory says because ''we have attached it to have this significance''. Anything you may say is clearly not maintream - or how we traditionally describe the BB.

[NEOWatcher]

Well, I've already established with another poster here that essentially we have dealt with BB appearing from a point is in fact what current theory says because ''we have attached it to have this significance''.

No; Earlier attempts at the theory said that.
It's been revised by Hawking

Hawking later revised his position in A Brief History of Time (1988) where he stated "There was in fact no singularity at the beginning of the universe" (p50). This revision followed from quantum mechanics, in which general relativity must break down at times less than the Planck time. Hence general relativity cannot be used to show a singularity.

[Aethelwulf]

No; Earlier attempts at the theory said that.
It's been revised by Hawking

Read my Times below Planck Time thread in technology.

I have debated this topic concerning Hawkings idea's and they are mostly circular. I don't find it all too surprising Hawking has revised his beliefs. Penrose who wrote the singularity theorems with him, now believes in a cyclic universe theory.

[Aethelwulf]

The are just attempts on getting QM's to describe something - just because they do not permit singularities because of the violation of the uncertainty principle does not surprise me either - I'd expect that the beginning of time was so unique that perhaps a violation like this is to be expected.

[Shaula]

Well, I've already established with another poster here that essentially we have dealt with BB appearing from a point is in fact what current theory says because ''we have attached it to have this significance''. Anything you may say is clearly not maintream - or how we traditionally describe the BB.

We being who? I can vouch for a couple of university's Astronomy departments. But I guess that is nothing next your interpretation of what another person on an internet forum said.

Sorry, no matter how you squirm it does not change the fact that the simplistic extrapolations you present here are not how the topic is taught or interpreted these days. Your position is no more valid than that of someone who seems a kitten grow and predicts that one day it will be larger than the planet.

[Swift]

I have moved this thread from Q&A to Astronomy.

The explanation of the Q&A forum says the following:

This section of the forum is for astronomy and space exploration questions with straightforward, generally accepted answers.

Questions that are likely to lead to extended discussion about the correct answer, or that have no clearcut correct answer, should be posted in the forum most appropriate to the topic of the question. If a question does lead to such discussion, it may be split off or moved entirely to a more appropriate forum by a moderator. Since it's hard to tell how a discussion will go, posting such questions will generally be treated as a judgment matter and not a rule violation.

Questions taking issue or raising concerns with the mainstream viewpoint should be posted in the ATM forum. Posting questions along these lines will generally be treated as a rule violation.

For the moment, we'll see if this discussion can stay out of ATM

And I really don't want to hear the ''this is not what mainstream says'' rubbish. I have read plenty texts on this subject and I can assure you, this is what maintream says.

Aethelwulf,

You really need to lose the attitude. To open a thread with a chip already installed on your shoulder is asking for trouble.

[Jeff Root]

Penrose showed conclusively that general relativity
predicts a singularity at time zero. But the concept
of a singularity doesn't work in quantum mechanics.
So either general relativity or quantum mechanics
or both need to be modified in order to avoid giving
conflicting predictions at and close to time zero.
So the current best model is unable to make good
predictions about conditions close to time zero.

-- Jeff, in Minneapolis

[Aethelwulf]

Also, I've learned to take what Hawking says with a pinch of salt now. He's certainly not the beginning and end of discussion. He has already made fanticiful claims of a theory of everything, along with thinking that information is lost in black holes. He's been wrong and pretty much a science dictator all his life.

[Aethelwulf]

Penrose showed conclusively that general relativity
predicts a singularity at time zero. But the concept
of a singularity doesn't work in quantum mechanics.
So either general relativity or quantum mechanics
or both need to be modified in order not to give
conflicting predictions at and close to time zero.
So the current best model is unable to make good
predictions about conditions close to time zero.

-- Jeff, in Minneapolis

Yes true, the reason has to do with the Uncertainty Principle. You can't squeeze energy into a point without examining a violation in QM.

[Aethelwulf]

You really need to lose the attitude. To open a thread with a chip already installed on your shoulder is asking for trouble.[/COLOR]

Sorry.

[Cougar]

But the concept
of a singularity doesn't work in quantum mechanics.

Well, it doesn't work in mathematics, either, and all these theories are expressed via mathematics. It's like dividing by zero. It doesn't work. It's undefined.

Also, I've learned to take what Hawking says with a pinch of salt now. He's certainly not the beginning and end of discussion.

Good, and correct.

He has already made fanticiful claims of a theory of everything, along with thinking that information is lost in black holes. He's been wrong...

Yes, on some things he has been wrong. Same as Einstein.

...and pretty much a science dictator all his life.

Well, that's taking it too far. He has over 200 publications, most of which are way over your head and mine, so how would we know? And of course, there are no science dictators, only peers.

[Aethelwulf]

Well, that's taking it too far. He has over 200 publications, most of which are way over your head and mine, so how would we know? And of course, there are no science dictators, only peers.

Maybe it was taking it too far. He does seem to move the finger more in his assertions nowadays mind you. Like dictating a theory of everything recently, to his conjecture that information is lost in a black hole... and he wouldn't listen to the physicists. I remember the so-called Susskind-Hawking debates on information. The physicists would get quite brutal sometimes.

I am a big Susskind fan however.

[Cougar]

He does seem to move the finger more in his assertions nowadays mind you. Like dictating a theory of everything recently...

He may be a very knowledgeable physicist, but I never thought much of his books, especially his latest. He is not a great popularizer. Many others are much better at that. And I thought that latest book of his (and Mlodinow) was nothing new - he just took Guth's "free lunch" idea, which is decades old, and called it the Grand Design. I'm not saying it's wrong. I'm saying it's old. On the other hand, the book did show Stephen's sense of humor. He's a pretty funny guy, which is somewhat remarkable, given his illness.

I am a big Susskind fan however.

That may be a mistake. I'm often a big fan of whoever wrote the book I'm currently reading. I was very impressed with Alex Vilenkin's entry. But there's currently no way to test his idea, and it doesn't look like there's going to be for quite a long time, so my fandom has waned. Now I'm beginning to wonder why so many respected physicists, including Susskind, are speculating about ideas that are not currently testable and, in fact, may never be!

[Aethelwulf]

He may be a very knowledgeable physicist, but I never thought much of his books, especially his latest. He is not a great popularizer. Many others are much better at that. And I thought that latest book of his (and Mlodinow) was nothing new - he just took Guth's "free lunch" idea, which is decades old, and called it the Grand Design. I'm not saying it's wrong. I'm saying it's old. On the other hand, the book did show Stephen's sense of humor. He's a pretty funny guy, which is somewhat remarkable, given his illness.



That may be a mistake. I'm often a big fan of whoever wrote the book I'm currently reading. I was very impressed with Alex Vilenkin's entry. But there's currently no way to test his idea, and it doesn't look like there's going to be for quite a long time, so my fandom has waned. Now I'm beginning to wonder why so many respected physicists, including Susskind, are speculating about ideas that are not currently testable and, in fact, may never be!

I think half the time he has been popularized is because of his ground-breaking work... more recently though, he has acted as a judge on scientific theories... most of this I bet was a publicity stunt... a certain Baron from my country made harsh remarks on this theory of everything... I will look and find details.

[Jeff Root]

But the concept of a singularity doesn't work in
quantum mechanics.

Well, it doesn't work in mathematics, either, and all
these theories are expressed via mathematics. It's
like dividing by zero. It doesn't work. It's undefined.

Mathematically it works just fine. General relativity
predicts a singularity, and that by itself is no problem.

The singularity that general relativity predicts is the
beginning of time.

The problem arises when you try to reconcile what GR
predicts with what other branches of science predict.

The example of a mathematical singularity that I keep
presenting is the Earth's poles. When you are at the
south pole, you no longer have a longitude, because
the longitude is, as you say, undefined. But that does
not cause any physical problem. It is possible to be
at the south pole and have no longitude. The problem
with time zero is not mathematical.

-- Jeff, in Minneapolis

[trinitree88]

I think half the time he has been popularized is because of his ground-breaking work... more recently though, he has acted as a judge on scientific theories... most of this I bet was a publicity stunt... a certain Baron from my country made harsh remarks on this theory of everything... I will look and find details.

Aethelwulf. After Einstein completed the General Theory in 1915, he embarked upon an attempt to unify all the forces of physics, having seen the early success of Maxwell in unifying electricity, magnetism and optics, under the one umbrella of electromagnetism. At the time he was widely regarded as a fool amongst his peers, who nevertheless respected his earlier work. Towards the end of his career, after he passed away,strides were made in unifying the strong and weak forces by,notably, Feynmann, Schwinger, and Tomonaga, and then, in the sixties, Weinberg, Glashow, and Salaam managed to produce the electroweak synthesis,predicting new particles (the Z ⁰) and it's neutral currents. Only then did many see that Einstein's instinct for picking the correct problem to work on was as unerring as it was in 1905......the big prize would be total unification of the strong, weak, electromagnetic and gravitational forces...the unified field theory for which he endured much disparate ridicule.
In a similar vein, Hawking proved early on to be a math prodigy, and as such developed physical insight into the processes proximate to event horizons, melding developing mathematical theories into his physics and engaging some of the best minds in the world in his erudite excursions, which require training similar to his to read explicitly. He hardly has warranted being called a dictator, but merely does his job of asking questions....something scientists thrive on, and he often picks gentleman's bets of minor worth but immense fun and bragging rights...like a pair of friends fishing or playing golf for beers.
So, we don't know it all. That's the game. Data banks slowly unravel the intersecting error ellipses of experiments and continue to refine our searches for new physics...like the Higgs @ the LHC, to pick new models. It's an exciting time to have an interest in physics. pete


SEE:http://www-d0.fnal.gov/Run2Physics/higgs/

[Aethelwulf]

Mathematically it works just fine. General relativity
predicts a singularity, and that by itself is no problem.

The singularity that general relativity predicts is the
beginning of time.

The problem arises when you try to reconcile what GR
predicts with what other branches of science predict.

The example of a mathematical singularity that I keep
presenting is the Earth's poles. When you are at the
south pole, you no longer have a longitude, because
the longitude is, as you say, undefined. But that does
not cause any physical problem. It is possible to be
at the south pole and have no longitude. The problem
with time zero is not mathematical.

-- Jeff, in Minneapolis

This is true. Mathematically, from a relativistic viewpoint there are no troubles.. in fact, infinitely small points are very much welcome. It's only when you invoke QM that troubles begin... or so they say. Some of us, want to embrace these difficulties than rather seeing it as the ultimatum of all problems.

[Aethelwulf]

Aethelwulf. After Einstein completed the General Theory in 1915, he embarked upon an attempt to unify all the forces of physics, having seen the early success of Maxwell in unifying electricity, magnetism and optics, under the one umbrella of electromagnetism. At the time he was widely regarded as a fool amongst his peers, who nevertheless respected his earlier work. Towards the end of his career, after he passed away,strides were made in unifying the strong and weak forces by,notably, Feynmann, Schwinger, and Tomonaga, and then, in the sixties, Weinberg, Glashow, and Salaam managed to produce the electroweak synthesis,predicting new particles (the Z ⁰) and it's neutral currents. Only then did many see that Einstein's instinct for picking the correct problem to work on was as unerring as it was in 1905......the big prize would be total unification of the strong, weak, electromagnetic and gravitational forces...the unified field theory for which he endured much disparate ridicule.
In a similar vein, Hawking proved early on to be a math prodigy, and as such developed physical insight into the processes proximate to event horizons, melding developing mathematical theories into his physics and engaging some of the best minds in the world in his erudite excursions, which require training similar to his to read explicitly. He hardly has warranted being called a dictator, but merely does his job of asking questions....something scientists thrive on, and he often picks gentleman's bets of minor worth but immense fun and bragging rights...like a pair of friends fishing or playing golf for beers.
So, we don't know it all. That's the game. Data banks slowly unravel the intersecting error ellipses of experiments and continue to refine our searches for new physics...like the Higgs @ the LHC, to pick new models. It's an exciting time to have an interest in physics. pete


SEE:http://www-d0.fnal.gov/Run2Physics/higgs/

I'm not saying we know it all. What I am saying is that we should not throw out these infinities as a breakdown in the theory. I believe also Dirac held a similar point. In regards to current day theory, we try and renormalize these theories... Dirac was largely unsupportive of this idea.

[noncryptic]

Yet, BB arose from such a state, we are led to believe. This is mainstream, again.

Of mainstream scientific theory (GR, QCD/QED/QM) only one says there is a singularity, and that prediction can not be verified (surely not soon, and possibly not in principal). In that sense a singularity is much less a fact than something like time dilation.

Besides theory there is a mainstream model of how the universe works: the standard cosmological model, of which the 'moment of creation' is not a part.

So it is true only in a very limited sense that the mainstream says there is a singularity at the beginning of the BB (or for that matter, at the center of a black hole).

[Aethelwulf]

I actually don't care anymore, only that the mainstream model does predict a point. Where my trouble had laid, was with people who claimed the BB did not present a model far in the past that a curvature was infinite. Saying our model did not is highly against the mainstream.

[Troka]

Hello,

The BB, as taught in my astrophysics class, starts AFTER the 10^-37 seconds, not at the beginning. As stated, since the laws of physics did not operate before that slight amount (but very important) time, there is no singularity in the BB. It is indeed overuse of that term that has caused confusion

[Cougar]

The example of a mathematical singularity that I keep
presenting is the Earth's poles. When you are at the
south pole, you no longer have a longitude, because
the longitude is, as you say, undefined. But that does
not cause any physical problem. It is possible to be
at the south pole and have no longitude. The problem
with time zero is not mathematical.

Ha ha. The example I always recall is the equation for an orbiting spacecraft around a central mass. When the spacecraft impacts the central mass, that's a singularity in your equation. This does cause a physical problem.

[Shaula]

I actually don't care anymore, only that the mainstream model does predict a point. Where my trouble had laid, was with people who claimed the BB did not present a model far in the past that a curvature was infinite. Saying our model did not is highly against the mainstream.

BB theory is more than just GR. It does not predict a point because the model breaks down before then making any extrapolations invalid predictions. That is the mainstream view, taught in universities. If you are willing to make this sort of extrapolation why not go further? After it reaches a point the universe will expand again but with its spatial dimensions swapped. After all - plotting lines on a graph and then putting a straight line through them implies that. Got to be true.

[Jeff Root]

Hello, Troka!

The BB, as taught in my astrophysics class, starts
AFTER the 10^-37 seconds, not at the beginning.

The Big Bang was the beginning, if there was one, and
whenever it may have been. The description of the Big
Bang given in your class, on the other hand, may have
begun with events after 10^-37 seconds, as there isn't
anything known about any earlier time.

(Actually, I would argue that nothing earlier than about
one second is remotely close to being a sure thing. At
that time nucleosynthesis began, and observations of
isotopic abundances support calculations of the rates
of change of density and temperature over the next
couple of minutes.)

As stated, since the laws of physics did not operate
before that slight amount (but very important) time,
there is no singularity in the BB.

I think it is safe to say that the laws of physics operate
at all times. But we don't necessarily know what those
laws are. There is no reason to think that the laws we
currently know did not operate at the very beginning.
However, there is very good reason to think that the
laws we know are not enough. Something beyond the
known laws happened at the beginning. Something
in addition to the currently-known laws.

General relativity predicts a singularity at the beginning.
Quantum mechanics says that prediction can't be right.
So we don't know whether there was a singularity or not.
We need to extend the laws of physics to find out.

-- Jeff, in Minneapolis

[Strange]

The Big Bang was the beginning

Do you have a reference to support that, or are you just basing it on what the name sounds like it should describe. You have people who studied astrophysics/cosmology in the past saying that isn't the case. Now we have a current student saying that it isn't the case. Even good old Wikipedia says "The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe.[1]"

[Jeff Root]

Perhaps I should have said that the Big Bang was the
beginning of everything that we know of: The observable
Universe and at least some distance beyond what we can
observe. It was the beginning of the cosmic expansion
that we observe. Something may well have existed before
that, and something may exist which did not participate in
the Big Bang (other universes in the multiverse hypothesis).

Saying that the Big Bang started after the Big Bang started
doesn't work for me. Consistent descriptions of conditions
start a miniscule fraction of a second after time zero. Time
zero is defined by the Big Bang theory.


Some definitions or descriptions of "Big Bang":

Google.com

1.The explosion of dense matter that, according to current
cosmological theories, marked the origin of the universe


http://wordnetweb.princeton.edu/perl/webwn?s=big%20bang

(cosmology) the cosmic explosion that is hypothesized to
have marked the origin of the universe


en.wikipedia.org/wiki/Big_Bang

The Big Bang was an event which led to the formation
of the universe, according to the prevailing cosmological
theory of the universe's early development (known as the
Big Bang theory or Big Bang model).


-- Jeff, in Minneapolis