Modern Cosmology: Science or Folktale?

[quantum123]

American Scientists Online:
see full issue: September-October 2007
Other Formats: PDF
Modern Cosmology: Science or Folktale?
Current cosmological theory rests on a disturbingly small number of independent observations
Michael J. Disney

http://www.americanscientist.org/template/AssetDetail/assetid/55839/page/1

 

[mgb_phys]

Mike Disney is a well known astronomer so it's a little tongue in cheek.
There is good evidence for the big bang cosmology. There isn't good observational evidence to fit parameters for every detail.
It's a bit like evolution, everybody accepts that it's true even if you don't have a theory that tells you mutation rates for every gene in every animal.

 

[turbo]

I don't know if this is tongue-in-cheek or not. Certainly the article is much kinder and gentler than the paper he published on the subject in 2000.

http://arxiv.org/abs/astro-ph/0009020

 

[mgb_phys]

Whats that quote about science being good value because you get such a large amount of theory from such a small amount of data. It's especially true of cosmology.
There is definitely a maths/theoretical physics end of cosmology where the theory is everything and if it happens to fit some observational data - good, but that doesn't really bother the theorists.

Still it's better than string theory - for each new result you have to add two new free parameters

 

[Wallace]

Astronomy is always going to struggle to be as 'certain' as other sciences since we can only ever watch the sky and not set up repeated experiments (make your own stars, pulsars, galaxies, unvierses etc). Strangely though some astronomers seem to think that their field containing more theoretical conjecture than evidence is somehow infinitely more robust than another.

We really have no idea how even the humblest of stars form, in that there are barriers to formation that we don't understand how protostars overcome to form stars. Despite this there are plenty of people working on star formation with oodles of theories supported by suppositions based on the blobology of gas clouds. Despite this no one writes the kind of diatribes that cosmology cops all the time about this field! (I use star formation as an example, you could equally point to pulsars, AGN, galaxy formation and just about any other astronomy field and make similar arguments).

 

[Chronos]

Michael Disney has authored some rather odd ATM papers, such as:
The Case Against Cosmology [arXiv:astro-ph/0009020], as noted by Turbo.
He appears to have since cleaned up his act, having collaborated on several good papers in the past several years. I like ATM ideas to the extent they are supported by good observational evidence.

 

[oldman]

Whats that quote about science being good value because you get such a large amount of theory from such a small amount of data. It's especially true of cosmology.

The quote you need is from Mark Twain in Life on the Mississippi
:

“There is something fascinating about science. One gets such wholesale returns of
conjecture out of such a trifling investment in fact.”

See for example: The Family Mark Twain, Harper& Brothers, New York, p. 87.

It is particularly apt for much of modern theoretical physics, which is starving for lack of new observations. But it is less apt for cosmology, since this suffers from contradiction and confusion, rather than starvation, as Disney keeps pointing out.

 

[Wallace]

cosmology ... suffers from contradiction and confusion

Such as?

 

[oldman]

Such as?

Contradiction ... baryon densities obtained from elemental abundances and from WMAP analysis are different. See August Physics World .

Confusion... do all cosmologsts believe that inflation really happened? And who knows what Dark Energy is, if it exists?

I think that Mike Disney gives a fair summary, with the puzzling exception of crediting Bosma instead of Vera Rubin with the galaxy rotation discrepancies which suggest dark matter.

 

[George Jones]

Contradiction ... baryon densities obtained from elemental abundances and from WMAP analysis are different. See August Physics World .

Here's http://physicsworld.com/cws/article/print/30680.

 

[Wallace]

Contradiction ... baryon densities obtained from elemental abundances and from WMAP analysis are different. See August Physics World .

They are a little different. It's an intriguing issue. But you've missed the point that the fact that they are close at all is amazing. Not to mention the rest of the things that are measured to be so startlingly similar with a wide range of independent measurements. It's a kind of glass 95% full, 5% empty kind of thing.

Confusion... do all cosmologsts believe that inflation really happened? And who knows what Dark Energy is, if it exists?

How does this mean there is confusion? We don't know what dark energy is, if it even exists but that doesn't mean we are confused about it. 'Dark energy' is a proxy term for a whole range of possible explanation for the accelerated expansion which is seen independently across a wide range of different observations. There are unknowns in the theory, which is what makes it exciting, but can hardly be described as confusion.

I think that Mike Disney gives a fair summary, with the puzzling exception of crediting Bosma instead of Vera Rubin with the galaxy rotation discrepancies which suggest dark matter.

As I pointed out above Disney's arguments are as applicable to any part of astronomy and not some major issue with cosmology.

 

[oldman]

They are a little different. It's an intriguing issue. But you've missed the point that the fact that they are close at all is amazing. ...It's a kind of glass 95% full, 5% empty kind of thing.

Yes it is.

...'Dark energy' is a proxy term for a whole range of possible explanation for the accelerated expansion which is seen independently across a wide range of different observations. There are unknowns in the theory, which is what makes it exciting, but can hardly be described as confusion.

Again, depends on the way you look at "the theory", if there is only one.

In really ordinary physics (say solid state) researchers may at first not have understood how the constituents of a solid (electrons, atoms) could behave to produce the strange fractional quantum Hall effect. It was then "exciting" to work out this odd puzzle. But in the case of dark energy which, of which you comment: "We don't know what dark energy is, if it even exists". How then can those who strive to shape this cornerstone of modern cosmology be anything other than confused, i.e. "lacking order and difficult to understand" (OED)?

 

[oldman]

Here's http://physicsworld.com/cws/article/print/30680.

Thanks for the help.