The Big Bang model says that the Universe was hotter and denser in the past.

The BBT standard model provides conditions beyond which (earlier than which) we simply cannot even make educated guesses.

So, based on what we observe today, we "run the clock backward" in steps or stages, verifying the results of the theoretical models by then running the clock forward again to see if it produces results that match what we observe. We then tweak the models, run the clock backward and forward, and continue in this fashion until we find one that works reliably well.

Each time a major new finding or observation requires it, we go through the same scenario.

Along the way we find many things that do not work at all. As that happens we hone finer and finer the set of conditions that we think Must Have pertained to result in the model that does work.

This process of iterative refinement verifies or falsifies assumptions and results in a theory that we hold to be more accurate.

The currently accepted estimates for the age of the Universe are based on this theory and standard  model which, as I pointed out initially, has a limit beyond which it can't make predictions or assumptions. It is from that point that we measure time (forward) and thus what we call the Age of the Universe.

Ideas like string and brane theory, no matter how mathematically elegant, suffer from an even worse problem (they can't be observationally verified given any means we currently have). So, while they may be acceptable mathematical theory, they are not widely held scientific theory. A great many people are working on these ideas, so there is every chance they may become scientific theory.

The BBT, however, makes many predictions we actually do observe -- so it is the model we accept today.

 Hi chipdatajeffB,

I agree with all you said.  So do you agree with me that we do not presently know the age of the

Universe.  Do you agree that it is wrong to say that the Universe is 14 Billion years old?

  We should unstead says that we have a model that describes up to a certain level of details the expansion during the last 14 Billion years  but it does not allow us to extrapolate further into the past. 

 - LouisB

The Age of the Universe according to Scientific studies keeps getting older and for our so called  modern time it has reached its current age mainly through the BBT. The universe may be a lot more older, three or five times more than 14 billion years. First we must take into accound events that took place before the so called BBT and how long these events were in motions. Was there a cooling period before there was a hot period or before the more hostile elements race towards a nucleous and causing a cataclismic implosion or explosion. In measuring the age of the Universe one must then asked -- do we start from the first formation -- the sun or from the first orbiting planet -- It will be more correct to say -- when did the first Galaxy formed but since there are still many more galaxy to be observed or to be located or discoverd that question will never be answer. We are then left with only our Galaxy and our Universe. So the question should be -- How old is our Galaxy? Its a much greater number than you can imagine and much more than 14 billion years old.  

LouisB:

 

 Hi chipdatajeffB,

I agree with all you said.  So do you agree with me that we do not presently know the age of the

Universe.  Do you agree that it is wrong to say that the Universe is 14 Billion years old?

The BBT itself can't make any statement about what happened before what it calls t=0. The BBT postulates that spacetime itself was created in the event that happened at that time.

Additional ideas that attempt to address "what came before" t=0 are in obvious disagreement with a fundamental tenet of the BBT.

At the moment, the BBT models that are generally accepted hold that the universe is on the order of 13.5 billion years, give or take some few hundred million years.

fluflu:

The universe may be a lot more older, three or five times more than 14 billion years.

If ideas like a cyclic universe are correct, then this is axiomatic. The problem is finding any evidence that supports a cyclic universe. Otherwise, postulating about events prior to the BB is like asking about what is north of north: the answer must necessarily be indeterminate, if not outright undefined. 

That is, from the scientific perspective.

... It will be more correct to say -- when did the first Galaxy formed

Not if the question is about how old the Universe may be. It may be an important question, for sure, but it doesn't give us the age of the Universe itself.

... but since there are still many more galaxy to be observed or to be located or discoverd that question will never be answer.

Not to researchers working on the question of when the first galaxies formed. While it would help to know about older, and older galaxies (presumably to be discovered by new abilities -- such as larger telescopes -- to look further and further back in time), it is not required in order to build a valid model. Such new observations would certainly help to calibrate, validate, or falsify any such model.

We are then left with only our Galaxy and our Universe. So the question should be -- How old is our Galaxy? Its a much greater number than you can imagine and much more than 14 billion years old.  

You could make a statement like that philosophically, but scientifically you'd be required to back it up with observational data.

G'day from the land of ozzzzz

Chip you said that the BBT is supported by observations?

Can you list these observations as evidence.

Harry Costas:

Chip you said that the BBT is supported by observations?

Can you list these observations as evidence.

Haven't we gone through this before . . . before . . . before?

Harry Costas:

G'day from the land of ozzzzz

Chip you said that the BBT is supported by observations?

Can you list these observations as evidence.

Harry: We've had this conversation before. I've stopped following you around your posts asking you similar questions about your evidence. Please do the same for me in return. The evidence provided in support of the BBT is all over these forums. I've pointed it out to you before.

You contniue to ignore it. In another post you stated flatly that there are stars in the Milky Way older than 20 billion years. I asked you for a citation for that, or a paper in support of it. You ignored me and later changed your figure to 17 billion years. I asked you again and you ignored me.

This is trollish behavior. If you do not stop it, I will ask that you be banned from this forum.

It is okay for you to post your alternative ideas about cosmology. That is no problem. It is certainly okay to disagree.

But continually challenging me and others in this way is trollish behavior and it will not be allowed to continue here.

The age of anything that exist can be dertemine by one mean or another. The age of our Sun can be determine as is the age of our Moon and our planet Earth. We can go back in time and place each cycles of events but the further we go in dertemining the Age of the objects which we observe the more obscure these age becomes as we get to the Age of the Universe. The BBT is one of the best in determining such age but it has its flaws cause is not conclusived. I believe that once the age of our Galaxy is determine at least 90% correct than we will be more closely to knowing exactly the Age of the Universe. Science is not exact cause when it comes to such an age, we are talking about astronomical numbers which are so distant that makes our present knowlege too infant. If light was to recede from an initial event as it travels through space and be reflected back to the original event then we will for sure know the age of our Galaxy and our Universe.

G'day from the land of ozzzzz

Hello chip you do not have to provide what ever evidence you have to supoort the BBT. Its only for the new comes who read your comment.

As for the age of the universe thats another issue.

Where do you start, how do you account for the rejuvination and formation of stars and new elements. How do you account for galaxy merging and the evolution of galaxy form and formation of over a 100 billion galaxies in 13.2 Gyrs deep field images, that means 500 million years to form such super structures.

If you can support this by using science evidence I'm all ears.  

It was just explained how the estimate of the age of the universe came to be.  It is pretty straightforward.  All of the universe would have come to be at one point at about that far back in time.  Telescopes are able to peer almost that far back in time as well, and we see proto-galaxies in great number, showing that they formwed rather quickly, and merged as time went on.  They carry these photo's in the very magazine who's forum you are in.  Do you not read the magazine? 

They have a fairly good idea of how the simplist elements came into being, forming the first generational stars, which then spewed out heavier elements.  Their measurements also fit what they know as to how physics works.  The percentage of elements found fits with what they know should work, if the BB theory is valid.  Maybe you should read up on the BB theory and find out why most scientists and astronomers accept it.  To deny what photographic and scientific instruments have measured seems rather strange to me.

Are there questions as to how and when things formed exactly.  Yes.  Why?  Because we weren't there and the initial beginning conditions are at this point beyond our reach and comprehension.  Does this mean that it didn't happen?  We have the evidence and pictures, so why should we deny it.  That would be even more stupid. 

Alternative theories have really no evidence for what they want you to believe.  It is based solely on misrepresentation and faith.

Dusty_Matter:

Alternative theories have really no evidence for what they want you to believe.  It is based solely on misrepresentation and faith.

There is plenty of room for misunderstanding. It happens to everyone at some time. The questions we are talking about here are, after all, really BIG ones. And the answers ultimately lie in information from the very remote past.

I wouldn't go so far as to say that in general there is misrepresentation, though it may be true in some cases. I definitely would say that some cases are more a matter of faith and less a matter of incomplete understanding or research.

One of the problems with actually doing this sort of science is that if you get too interested in one particular point of view you miss important clues along other lines of evidence. So, it's important for researchers not only to keep an open mind, but also to be alert to alternatives that might require a change in one's own interpretation.

When we discuss the BBT, it's good to keep in mind that it is not simply a "favored interpretation" or an ad hoc Idea, but rather a Theory. No surviving alternative offered thus far has reached the status of Theory.

Does it explain galaxy evolution? Not fully. At least one of the following is true:

1. We don't yet have a valid explanation for galaxy evolution.
2. We have a valid, but incomplete, explanation for galaxy evolution.
3. Some part of the BBT that is in conflict with a new and valid explanation of galaxy evolution is itself invalid or incomplete.

None of this means the BBT is fundamentally flawed.

  This doesn't seem to be such startling news to me. As far as I know, the figures given in the Cosmology texts I read usually state that the age of the Universe was 13 to 15 billion years old. The only catch was, that one could not determine the SIZE of the Universe from this. It was explained that while nothing can travel faster than light through space, space is allowed to travel as fast as it wants. This means the expansion of the early Universe could have been rather fast indeed. Also, the "lost" time that's being referred to, is a very small length of time where our current understanding of physics doesn't apply. Last I heard, it was a fraction of a fraction of a second.

  We still don't know if it's a cyclic Universe or if it will just keep expanding and cooling.

 t=0 is now.  We run back the clock 14 billion years on the BBT equations. at t = -14 billion years is the boundary of validity of the equations

Let assume there exist another set of equations describing the Universe for t< - 14 billion years.

 The system had an evolution before t=-14 billion years.  Nobody nows what it is.  It could be  a fraction of second as it could be infinity. 

 If you assume that it is a fraction of a second then it is a good approximation to say that the Universe is 14 billion years old.  But it is not necessary the case!

Hi Harry,

 When someone wants to know vaguely what is the big bang theory, there are plenty of short 1 or 2 pages explanation that can be found everywhere. 

I would be interested to see a similar short description of your position on cosmology.

- LouisB 

LouisB:

The system had an evolution before t=-14 billion years.  Nobody nows what it is.  It could be  a fraction of second as it could be infinity. 

That's another way of saying what the BBT says: given the tenets of the BBT as currently stated, there is no way to know about anything "before". That is, IF there was anything "before" then  the BB wiped out all traces of it. There is no way, using technology and knowledge we have today, to know anything about "earlier" times.

String Theory (so-called, as it is neither verifiable nor falsifiable) and Brane Theory (a mathematical theory with no current basis of observational evidence) represent attempts to delve into an alternative to the beginning as postulated by the BBT. They show mathematical promise, but as physical Theory they are (to quote the title of a book of the same name) so bad as to be "Not Even Wrong" ... they do show promise, however, and advances may give them a physical underpinning at some point.

Back again to the analogy of "What is north of north?", there simply is no way (currently) to know. So, to say "The Universe is older than 14 billion years old." is neither falsiable nor verifiable, but there also is no evidence to support it.

  Correct me if I'm mistaken, but, I thought String Theory was less about Cosmology as a whole and more a way to unify quantum physics with macro-physics. Elegant Universe explained it as basically two sets of rule books in current physics, one for large objects like planets orbiting the Sun, our physical world and a second one for the subatomic world where things get very strange indeed. String Theory, I thought was an attempt to have a "rule book" that covers both.

Darn it Jim, I'm a country plumber, not a physicist.....

kuzinov:

Darn it Jim, I'm a country plumber, not a physicist.....

Nice reference, Bones