# Gravity never zero

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Ivan, Dec 18, 2011.

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1. ### Robittybob1BannedBanned

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The more work that is done in increasing the size of the Universe, to the point of making it infinite as some are now saying, the less certain the Big Bang is in my opinion. It is very difficult to expand a walnut sized object into infinity in just 13.7 Billion years.

3. ### EmilValued Senior Member

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In my opinion, the Big Bang (if indeed it happened) was a local phenomenon in space and time.
Space and time was not created by the Big Bang.

5. ### originHeading towards oblivionValued Senior Member

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Personal opinions based on hunches are not usually the big drivers in science.

7. ### Robittybob1BannedBanned

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It's the ability to follow up on these hunches. They pay off if you can invest the time and energy into them.

8. ### OnlyMeValued Senior Member

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Origin, you miss the point by dissecting posts. Every comment becomes a discussion out of context.

Theories are no longer theories, once they are proven.

Sometimes, a portion of a theory may become proven and elevated to the level of an observed or tested fact, which may or may not also elevate the underlying theory to the same level.

The big bang remains an unproven theory. This is all I was saying. Well, that and a comment on the fact that all to often, many posters, myself included at times, talk about "theory" as if it were fact.

The fact, that people become psychologically dependent on their belief systems is well known and "proven". This applies in science as well as other areas.

At least some portion of the redshift is involved in circular reasoning.... The expansion of the universe is demonstrated by the redshift, which is caused by the expanding universe. That is circular reasoning... Note I did not say it was wrong. It just has not been proven and can be seen as circular reasoning.

Most of what we believe about the universe today, will almost certainly change over time, as it has down through the ages.

9. ### OnlyMeValued Senior Member

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Have you ever wondered why most of the really big shifts and changes in theoretical science come from young men and women just starting out intheir careers?

They are the one's with hunches and the time and freedom to explore them. They have not yet invested too much in their theories, to push them aside for new ideas.

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Like what?

11. ### originHeading towards oblivionValued Senior Member

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The operative word here is explore the ideas to see if they have merit. I was commenting on the lazy gits who say "in my opinion bla bla bla", they will never take the initative or expend the effort to educate themselves to move beyond the opinion point.

12. ### keith1Guest

You and your opinion remain as they always have been--objects withinyour walnut shell analogy. In this respect, your shell was always infinite in size. That was an easy one.

13. ### keith1Guest

It remains the most descriptive possibility of the dynamics possible, from the observed results. It must be close to those dynamics, in order to get these observed results.

14. ### keith1Guest

You cannot bandy what you cannot prove, nor inflect from observation.

15. ### OnlyMeValued Senior Member

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The tendency to discuss theory as fact has a long record and is not limited to any individual, or credentials. The specific quote that triggered my attempt at reminder of the difference between what is known as a matter of fact and what remains the subject of theory was,
I read the above, perhaps incorrectly as implying that we do know with certainty what happened after the initial $10^{-43}$ seconds, of the Big Bang. Theoretically yes. With certainty no.

Mark this one up to my current favorite complaint. I read as many research papers as I can these days. I am retired and have the time, most of the time. Most often credible papers make it clear that they are presenting a theory or their theory and often even point out their own flaws. By contrast in discussion groups theories are often described as if they were settled fact, rather than our best explanations.

I never really meant anything personal, but an example as you requested, might be general relativity. While it has been very successful and many predictions have been proven, the theory remains a theory and as a whole is yet to be raised beyond the level of theory.

The standard model of particle physics has been one of our great theoretical achievements and yet at very high energy levels it begins to return unreasonable results and predictions.

The big bang remains a theory with less experimental confirmation than either of the above. And yes it does fit observation well... But then we human beings have always been good at finding believable explanatintions that fit what we see, very nicely, until we discover things work differently than we thought.

As I mentioned earlier, I would say I am an agnostic as to what the beginning, if there was a beginning looked like..., way to long before my time.

I will say that I believe it is likely that both GR and what we currently know of QM will both look very different in another few hundred years. Even though they are our best descriptions and explanations of what and how we see the world today.

16. ### OnlyMeValued Senior Member

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It is close enough to explain things as they appear from our frame of reference, but we cannot step outside of the picture to see the whole of what is.

History is full of theories and ideas that were the best explanations of their day, which have as a matter of routine been replaced by a better explanation as our understand and knowledge has grown.

Just because an explanation is our best explanation now, does not mean it will be in the future or that it is even an accurate description. It is just the best we can do with what things look like, to us, now.

17. ### EmilValued Senior Member

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You forget one thing. You have to prove that space and time were created with the Big Bang.
Show the evidence and the reasoning leading to this hypothesis.

18. ### keith1Guest

No I don't. You're the one making the claims. You claim an existing space-time which must be disturbed by a new intruding, expanding space-time field. That evidence would be unobservable--beyond the event horizon.

Observable expanding spacetime exists along with, in the same setting, the same set, as-- the other observable forces. I'll venture that much.

19. ### EmilValued Senior Member

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So you understand that I claim an expanding space-time field ?

20. ### keith1Guest

Yeah, yeah, yeah everything is just hunky.

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lol...

22. ### hansdaValued Senior Member

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Creation of the universe has to be associated with some well tested and proven theories ; which have no limitaions or less limitations . 'The theory of creation of our universe' should not contradict any of the existing Law of Physics or else Physics is to be rewritten with new Laws . If we consider BB created the Universe , there is still remaining many unanswered questions and contradictions with the existing theories .

So, I think creation of the universe can be associated with either of the two well established Laws of Physics . These two Laws are : 1) " Mass and Energy neither can be created nor destroyed " and 2) GR .

The First Law has no limitations and is always TRUE . BB-theory would have contradicted this Law . Einstein's Equation , E = MC^2 ; supports this Law .

The Second Law of GR predicted the possibility of expansion and contraction of space . This theory can explain the expanding universe but still GR has some limitations .

So, we have to choose between these two Laws , to be associated with the creation of our Universe .

23. ### originHeading towards oblivionValued Senior Member

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No, we don't.

It really is rather simple. Evidence show that the universe is expanding and in the past was concentrated in a tiny volume comprised of only energy. This theory has made predictions, these predictions have turned out to be accurate. New data continues to support the big bang theory. Has it been proven? Of course not. Are there aspects of the creation of the universe that are a mystery? Of course there are. It may be that we will never know the answers. None of that is really relevent to the robust and well tested theory we call the big bang.

There is stuff we don't know about alot of things. It is OK, only religions and non-science people speak in absolutes. Besides, it would be a rather dull universe if we knew it all!