Re: the universe

Posted by Pasti on Feb 10, 2004 at 14:24

Re: the universe (DA Morgan)

"And I mean incorrect as in absolutely incorred, invalid, worthless. This is not a case like Newton vs. Einstein where a theory was extended. I think that anthropomorphized concepts like start and stop or beginning and end are meaningless. And will end up, in the future, as quaint 19th-20th century ideas that are the subject of party jokes like the no infamous "flat earth"."

You have lost me here.What has antropomorphism to do with inflationary cosmology?
Where exactly do you have a start/beginning and stop/end in FRW cosmology?You can do very well without it.Initial and final singularities, are just that: singularities in a classical theory and you cannot therefore take them seriously, despite the wide mediatization of the Big Bang, Crunch and Chill.Hence the "initial" and "final" concepts are ill defined physically, they have no sense except in the classical theory.The only thing that matters is "before" and "after", i.e. causality.
Things will change, very true, but I doubt, personally that is, that at the classical level there will be necessary to rethink cosmology from scratch.

"No offense taken but "for the time being" is about as large a waffle as you could have served on the breakfast plate."

It was intended as a joke in response to your remark...

"We know nothing about time. We don't even know what it is. Perhaps it pervades all other dimensions, perhaps it doesn't."

No, we don't know what time is, although we do have an ideea about its behavior.And it is a dimension, so it cannot exactly pervade other dimensions(to be as you say, you would have to have the time axis in the say, plane of the x&y axes - you do see the problem with linear indepencence and with z,don't you?)

"We can't even say for sure that it has granularity though I think most suspect it does."

We cannot prove that, although efforts are on the way (in very, very...veery early stage), but mathematically (and quite physically too) granularity appears as quite natural.It's just a well posed eigenvalue problem, in a rather complicated formalism.

"I am well aware of it. Remember where I teach. A lot of it goes well over my head but I am certainly in the thick of much of it."

Sounds good.But keep up a healthy dose of skepticism.

"I was referring to you personally. It often appears to me that you are thinking inside the box. A box created from string and M theory and uncertainty, etc. but still well inside the traditionalist box."

Actually, in my original post on this thread, I was just giving the traditional answer to someone who was asking exactly about the traditional cosmology.And whether I like it or not for the time being,thisis the model best supported by evidence.
I am not, or in all honesty I think I am not, thinking in the traditionalist box.Certainly not in the one created from string theory and M theory.I am not working on those, I am working on spin foams and related quantum gravity (on the granularity of space and time that you don't quite like).But when it comes to experimental evidence, that's it.The model that fits best the data and is reasonably accurate phenomenologically is the best at the time.Can't exactly argue with that.

"I don't think the answer is there. I think the answer is simpler. In fact so simple as to be beyond our grasp. I want to see challenges to constructs such as speed and accelleration."

Well, you read Lynds, I see, and the others.And yet,these concepts are still valid in the classical frame.And in QM, QED, etc you don't need challenges to these concepts, since they do not exist,they do not parallel the classical theory.

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