Unraveling the Big Bang Question: Escaping the Gravitational Pull of Black Holes

[PanTheory]

What do you mean by "scalar field math"? All this entails is throwing a scalar field into the energy momentum tensor, and using Einstein's field equations for GR, with a FRW metric.


I don't know the three people you've got in mind, but there are WAY more people than three that have worked on inflation, even in the early days.


No, there isn't "no general consensus that any of these theories have any validity": regardless of your Lagrangian these "theories" are all inflation; that is, they all do basically the same thing; produce an exponential period of expansion. What we don't know is the particular mechanism for inflation to take place. However we can still make predictions that agree with observations.



But who are you to decide how simple nature is? You can't decree that a theory is not simple enough to be correct The most you can do is, if presented with two theories making identical predictions, use Occam's razor to say that the simplest one is most likely to be true. Occam's razor says nothing about theories that make different predictions. I appear to be repeating myself here: is there something I am saying that you don't understand?

Occam's razor: "All else being equal, the simplest explanation for some phenomenon is more likely to be correct than more complicated explanations, that explanations of anything should make as few assumptions as possible.” In science today it is often currently stated as, "the simplest theory that fits the facts of a problem is the one that should be selected."

Cristo, Above is Occam's razor. In this version, it starts out by stating "all else being equal". Regardless of the simplicity, naturally, if a theory is a better predictor, it rules. I believe most scientists would agree that the better predictor is the better theory.

The Big Bang makes no current predictions that the majority of theorists would agree upon because to do so could provide a means to disprove the theory. The one prominent agreed- upon prediction is that the universe is 13.7B years old. Any theory that has made the most well-documented predictions that are agreed upon by a majority of theorists beforehand will eventually win out as these predictions are observed. These predictions must also be properly backed by related logic and mathematics.

 

[cristo]

Cristo, Above is Occam's razor. In this version, it starts out by stating "all else being equal". Regardless of the simplicity, naturally, if a theory is a better predictor, it rules. I believe most scientists would agree that the better predictor is the better theory.

That's precisely what I've said above: are you even reading my posts?

The Big Bang makes no current predictions that the majority of theorists would agree upon because to do so could provide a means to disprove the theory.

The big bang theory has made many predictions; all of which have agreed with observational data (hence why it is the most preferred cosmological model to date).

I take it from the lack of replies to my other points that you have conceded that inflation is not "plain wild."

Finally, you appear to be holding the point of view that theoretical physics today is some sort of conspiracy theory, with all the physicists covering up these other alternative theories and only promoting one for some reason or another. Perhaps you should apply Occam's razor to this argument: it is far more simple to draw the conclusion that the reason the big bang model is favoured is because it fits the observational data best!

 

[marcus]

The Big Bang makes no current predictions that the majority of theorists would agree upon because to do so could provide a means to disprove the theory. The one prominent agreed- upon prediction is that the universe is 13.7B years old. Any theory that has made the most well-documented predictions that are agreed upon by a majority of theorists beforehand will eventually win out as these predictions are observed. These predictions must also be properly backed by related logic and mathematics.

PanTheory you talk about "Big Bang theory" as if you knew what it was but what you say is so full of misinformation that I would be inclined (if I was a mod) to just erase your posts. Cristo is patiently trying to set you on the right track, but you better listen carefully.

"Big Bang theory" is a term used by the general public, not as a rule by scientists. In the scientific literature there is no "BB theory". what there is instead is a standard model of (expansion) cosmology based on Einstein GR.

this model has one of the most impressive records in the whole history of science of making predictions that later turned out right. One of the most remarkable was the prediction of the CMB in 1948 by Alpher and Gamow. It was found almost 20 years later, right where they said it would be (a few kelvin above absolute zero) by people who weren't even looking for it.

The model is derived from General Relativity as formulated around 1915. This has also made a number of amazingly accurate predictions that were later confirmed. It has passed all the tests devised so far, to remarkable precision. The first test was in 1919 when Eddington found light was getting bent by the amount the theory predicted. We have no other more useful reliable model of how gravity works.

Both GR, and the standard expansion cosmology model derived from it are extremely spare and economical (Occam would LIKE them )

Rather than a prediction (as you mistakenly call it) the big bang is a brief period of high density and very rapid expansion which is a CONSEQUENCE of the standard model. If the expansion model is correct then as a corollary there must have been a brief period like that. This is not a prediction of the sort used to test theories because it is in the past and we can't observe it. Our model makes numerous predictions that we can test and they check out. The fact that at one point the universe was hot and dense is a free consequence of a model that has been checked and verified by other means. If you buy the model, you get the big bang event as a free extra.

Your saying that the standard model cosmology (and by implication the prevailing theory of gravity) are unpredictive sounds unbelievably lame. Maybe we can help you find a book you can read, to get the basics straightened out. What books on cosmology have you read so far?

 

[Phrak]

Ocam's razor, burden of proof, identification with conspiracy, etc : so often asserted, never proved.

 

[PanTheory]

PanTheory you talk about "Big Bang theory" as if you knew what it was but what you say is so full of misinformation that I would be inclined (if I was a mod) to just erase your posts. Cristo is patiently trying to set you on the right track, but you better listen carefully.

"Big Bang theory" is a term used by the general public, not as a rule by scientists. In the scientific literature there is no "BB theory". what there is instead is a standard model of (expansion) cosmology based on Einstein GR.

this model has one of the most impressive records in the whole history of science of making predictions that later turned out right. One of the most remarkable was the prediction of the CMB in 1948 by Alpher and Gamow. It was found almost 20 years later, right where they said it would be (a few kelvin above absolute zero) by people who weren't even looking for it.

The model is derived from General Relativity as formulated around 1915. This has also made a number of amazingly accurate predictions that were later confirmed. It has passed all the tests devised so far, to remarkable precision. The first test was in 1919 when Eddington found light was getting bent by the amount the theory predicted. We have no other more useful reliable model of how gravity works.

Both GR, and the standard expansion cosmology model derived from it are extremely spare and economical (Occam would LIKE them )

Rather than a prediction (as you mistakenly call it) the big bang is a brief period of high density and very rapid expansion which is a CONSEQUENCE of the standard model. If the expansion model is correct then as a corollary there must have been a brief period like that. This is not a prediction of the sort used to test theories because it is in the past and we can't observe it. Our model makes numerous predictions that we can test and they check out. The fact that at one point the universe was hot and dense is a free consequence of a model that has been checked and verified by other means. If you buy the model, you get the big bang event as a free extra.

Your saying that the standard model cosmology (and by implication the prevailing theory of gravity) are unpredictive sounds unbelievably lame. Maybe we can help you find a book you can read, to get the basics straightened out. What books on cosmology have you read so far?

No Marcus, never said the Big Bang theory was a prediction, I said its theorists can't agree upon future predictions other than that the universe is 13.7B years old. Find another present prediction that is generally agreed upon. I've internet researched it for a long time. The only thing you ever find is an observation that some theorists asserts a prediction. Of course I believe them. But if you have hundreds of theorists making maybe hundreds of predictions, some of them will be right, but maybe for the wrong reason. What I'm saying is there never has been a consensus regarding (future) predictions, to do so what provide a way to falsify the theory. This isn't a conspiracy, it's simply the amount of theorists involved cannot agree.

What basis should we judge theories if they do not make predictions, and that almost every year observation come along that require continuous modification of the theory.

Wouldn't it be better if a theory became known, that made a great number of predictions that were continually observed with fewer contradictions and theory changes. Beside cosmology Einstein's theory of gravity does not explain why spiral galaxies retain their form for so long. Dark matter cannot explain this because it would have to have to have an uneven density throughout the galaxy. In theory nothing should be untouchable. Continually new or improved theory has put us where we are today and I don't believe these theoretic changes will ever end, at least not in the foreseeable future.

The BB is just short-hand for identifying the theory, no disrespect is intended. Many texts use this abbreviation to shorten the script. It's much simpler than saying: the standard model of (expansion) cosmology based upon Einstein's GR.

 

[PanTheory]

That's precisely what I've said above: are you even reading my posts?


The big bang theory has made many predictions; all of which have agreed with observational data (hence why it is the most preferred cosmological model to date).

I take it from the lack of replies to my other points that you have conceded that inflation is not "plain wild."

Finally, you appear to be holding the point of view that theoretical physics today is some sort of conspiracy theory, with all the physicists covering up these other alternative theories and only promoting one for some reason or another. Perhaps you should apply Occam's razor to this argument: it is far more simple to draw the conclusion that the reason the big bang model is favoured is because it fits the observational data best!

Cristo, I understood your arguments, I don't try to argue, just explain, or supply information. The conclusions are up to the person reading the information. Since you thought my explanations were adversarial, there certainly is no problem with that . When I was agreeing with some of your points you thought I was arguing, I think.

Gamow in '48' predicted a CMB of 50 degrees K prediction. Peebles in '60' a CMB radiation of minimum 10 degrees K prediction. Eddington in '26' MB secondary radiation of galactic matter heated by starlight 3.2 degees K prediction. First survey of omni-present intergalactic hydrogen 1997 Germulz observation at 21cm., 3 degrees K. Hydrogen in one form or another has been estimated to permeate our galactic space at a minimum density of about 6.8 atoms/protons per cubic meter, not including heavier matter and vast dust clouds.

Accordingly Eddington predicted the intragalatic radiation of non-stellar matter within .2K degrees accuracy in 1926 from what is presently observer as the radiation of just atomic hydrogen. No conclusion, just information.

 

[marcus]

The one prominent agreed- upon prediction is that the universe is 13.7B years old...

PanTheory you are wrong. The standard cosmology of model (and GR on which it's based) have made several remarkable testable predictions.

And what you offer as the ONE notable prediction is not even a good example of a prediction as far as I can see. The age of the current expansion phase doesn't seem like something you could observe. There are three or four different independent checks you can do on estimates of the age. Abundances of elements, various different star clusters and populations, etc. So age estimates are associated with various things you can predict and observe.

Ideally a prediction is something that says: "if you do such and such observation you will see thus and so, or measure X amount."
It gives you a definite experiment or observation you can use to check the veracity of the theory.

a prediction is not just a derived consequence. So I think you have given a bad example of one and moreover it is certainly NOT the ONE or even the main prediction.

 

[cristo]

This thread has run its course. PF is not a place for people to try and point out holes in the standard model of cosmology; that is what the peer-reviewed journals are for. PF is a place for people to learn, and not be confused by people with misconceptions giving incorrect lectures.

If anyone has any genuine questions that fall into the broad topic of this thread, then please feel free to start a new thread.