Cosmological expansion vs. stretching

[Drakkith]

Your citation of General Relativity as a point for the Big Bang team is salient. Because the genesis of all of this, for me, is relativity. I began with the simplistic notion of relative motion; you know, like a train that appears to be moving down its tracks westward when really the Earth is just spinning out from 'neath it. And it made me wonder if there's not some way in which the other galaxies appear to be receding when really it's our vantage point that's doing the receding-- sliding away into some other dimension.

But that's the beauty of GR. This recession IS a result of our galaxy receding from every other galaxy. Just like every other galaxy is receding from us.

Ultimately, my message is: Free your minds. Open up just a little. Current theory-- General Relativity, Big Bang, Etc., Etc.-- is not the be-all/end-all, obviously. Otherwise, we wouldn't still be waiting for GUFman.

Why do you think our minds are closed? The problem is that so many people THINK scientists minds are closed when it's usually the opposite. The only difference is that most scientists require that new things fit into the current laws of physics, as we have observe the universe to work that way. The average person doesn't think this way.

 

[marcus]

... know the degree to which the CMB is red shifted? We can't unless we know its source, and I have trouble believing that primordial photons released from their electron matrix is any better explanation than some partial component of this dark energy I keep hearing about (but never detecting ).
..Maybe only one explanation (Big Bang) that fits Occam's razor. But Occam wasn't half the sculptor that Gaudi was.

"Dark energy" is an unnecessary elaboration. At the classical GR level we just need to observe that two gravitational constants naturally occur in the GR equation naturally. Not only G but also Lambda (are allowed by the symmetries of the theory).

http://arxiv.org/abs/1002.3966/
"Why all these prejudices against a constant?"

Calling Lambda an "energy" is a dubious speculation which gets attention and creates a sense of importance. But so far there is no evidence that it is anything but a naturally occurring constant, comparable to Newton's G (which also occurs in the GR equation.)

There is no evidence for "dark energy" qua energy. Only that a certain constant in the currently accepted law of gravity is non-zero.

By contrast, the release of the CMB at about 3000 Kelvin is something that can be verified empirically. One can heat hydrogen gas to 3000 Kelvin and MEASURE the degree of ionization and calculate the mean free path of photons, at a given density. One can determine empirically how opaque or how transparent the hot glowing gas would be.

So this is familiar conventional physics, not at all comparable to the imaginative speculations about "dark energy".

I agree with your characterization of one of your comments as RHETORICAL. That's also how this comparison of CMB and "dark energy" looks.

Speaking of rhetoric, I like your ornamental flourish of comparing Occam with the great Barcelona architect Gaudi! Gaudi creates a strange Catalonian dreamland by putting every oddity on his buildings, whose lines waver as in a mirage.

Modern cosmology, by contrast, is remarkably simple and straightforward if properly understood. And in excellent overall agreement with data. More Nervi than Gaudi.
http://www.google.com/search?q=pier...QXzqfSyDw&sqi=2&ved=0CFUQsAQ&biw=1115&bih=627
(google images for "pier nervi")

 

[Chalnoth]

OK, good to know... good to know. (Another cool person in the armor of the peer review process, huh?)

Thanks.

Huh? No. It's just that the initial peer review that papers go through to get published is the beginning of peer review, not the end. Once published, a paper becomes part of the wider scientific discussion that rigorously (sometimes brutally) determines which papers are reasonable and which are not. The initial peer review to get a paper published is little more than a sanity check to ensure that published papers pass a minimum quality bar. The primary benefit we get from peer review is that the papers which are published are usually somewhat higher-quality than the earlier drafts first sent to the publishers. That and outright crankery is usually weeded out, but sometimes still manages to make it through.

 

[Neuroglider]

But that's the beauty of GR. This recession IS a result of our galaxy receding from every other galaxy. Just like every other galaxy is receding from us.

Yeah, I "get" that. The whole balloon (or raisin-laden leavened dough) thing. So maybe the time vortex is just another analogy for the expansion. Except... I think I now appreciate the fact that while the "down" direction (Z-axis) of the vortex might escape our perception, the X-Y would still be non-uniform. The tidal-effect comment may have been what did it for me-- that was nagging at the back of my mind the whole time. I kept thinking that it seems possible for the singularity's effect to overwhelm the tidal effect. But I suppose it would still be fractionally detectable, eh? Kinda like blue shifting within a local cluster... WAIT! Whaaaat?!

Why do you think our minds are closed?

Oh, I dunno. Maybe it has something to do with two different responders assuming I was talking about collapse when I never used that word and described in detail a scenario quite different from collapse. Or the several folks who kept telling me that the red shift is uniform when it is clearly not; generally uniform, perhaps, but not absolutely.

The problem is that so many people THINK scientists minds are closed when it's usually the opposite. The only difference is that most scientists require that new things fit into the current laws of physics, as we have observe the universe to work that way. The average person doesn't think this way.

Yep, I'm fully onboard with the need to fit current laws. Because, you see, I am a scientist. Of a different breed-- one that doesn't know all those laws of physics to which I nevertheless agree that we must adhere. Trying to learn here, thank you.

 

[Neuroglider]

Huh? No. It's just that the initial peer review that papers go through to get published is the beginning of peer review, not the end. Once published, a paper becomes part of the wider scientific discussion that rigorously (sometimes brutally) determines which papers are reasonable and which are not.

Spoken like a PLoS afficionado. It's hard to believe there's not a PLoS Physics!

As a biologist, I am somewhat frustrated by the inability to provide independent confirmation of the data I review in a submitted manuscript. I always assumed that the peer-review process was more satisfying in math and theoretical physics. In biology, repeating the experiments of a submitted paper would be exorbitantly expensive and time-consuming. But I tend to think of math and physics as "A-ha!" fields, driven by Gedankenexperimenten, where all the author has to do is lead the reader down a one-way mental street. It would seem that theorems and proofs of this sort could be reviewed relatively quickly and thoroughly in the first go. In the example of the Kashlinsky papers, you said it was the statistics that was their undoing. How hard is it for a reviewer to check stats? OK, that is acknowledged to be a question born of ignorance; the stats in biology are pretty simple. Physics/cosmology stats must be quite the bear. You have my sympathies on that one.

 

[Drakkith]

Oh, I dunno. Maybe it has something to do with two different responders assuming I was talking about collapse when I never used that word and described in detail a scenario quite different from collapse. Or the several folks who kept telling me that the red shift is uniform when it is clearly not; generally uniform, perhaps, but not absolutely.

This is a forum, not a textbook. If I tell you the redshift is uniform, I could very well mean that it is generally uniform, not absolutely. Or that once you take into account the variations in redshift from local motions it is absolute. In either case, I expect the difficulty is that you expect too much. No one here is getting paid to teach you, so don't expect 100% accurate unambiguous answers.

How about this. If you want to learn about cosmology then learn about it by asking questions, not by suggesting absurd models and then expecting us to find the glaring errors while you argue the entire time. I'm 90% certain this thread is a violation of PF rules on speculation and personal theories, so I'm done with it.

 

[berkeman]

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