Tuesday, December 06, 2011

What do I believe of Physics?

I wrote a post with this name in 2009 but the matter has come to mind again. The point is whether I actually believe the new results of physics in the same way that I believe facts about the moon (for example that the distance from the centre of the earth to the moon is between 350,000 and 450,000 km).

I am now in the Department of Science and High Technology, Como, the fourth department of which I have been a member since joining the University of Insubria. I have been successively in (i) the Department of the Sciences of Mathematics, Physics and Chemistry, Como,  then (ii) the Department of the Sciences of Culture, Politics and Information, Como, then (iii) the Department of Informatics and Communication, Varese, and finally (iv) the present department.

As a member of (iv) I thought I should attend some interdisciplinary seminars - in fact I have mentioned elsewhere how I miss seminars - and so I attended one about the most recent Nobel prizes in physics. It was a very good lecture with a brief introduction to the mathematics and physics of cosmological models, and a description of measurements which lead to the idea that the expansion of the universe is accelerating. When I was a student in Canberra I remember hearing about the work of Allan Sandage surveying Cepheid variable stars to estimate Hubble's constant (his colleage Olin J. Eggen was at Stromlo observatory). I thought at the time that the measurements were discutibile, they were not far fetched but I certainly did not believe the results in the sense mentioned above.

The newer Nobel prize work involves the extension of the measurements using supernovae. I am even more cautious about this.

The last part of the lecture was a beautiful graphic of the history of the universe from the big bang, through inflation etc, to the current accelerating stage with 75% of the universe being dark (matter or energy). This seems to me to be completely speculative.

The first question from the audience was from a physicist who asked  "do you believe this?". It seemed to me from the involved response  (in rapid Italian, and for that I am unsure) that the speaker himself found the matter speculative. Certainly from the question at least one physicist present did.

I do not touch here on the works of Deutsch and of Tegmark which to me are beyond speculation.

Update I was talking to a physicist today about my doubts. He said "Well, you don't have the competence to judge!".



Blogger Rider said...

The response of the physicist is unbelievable!!
There is an old engineering trick I learned from the physicists when I was grading their math tests as a grad student a long time ago:
Start off on a problem and take it as far as you can until you get stuck. Next take the desired answer and work it backwards until it resembles something in the first step. Now apply a "delta smudge function" to connect both ends, and defy the marker to find it.
I often get the impression this is how physics connects the math model with observation.
It may be appropriate to remind the physicist you were speaking with that physics is much too hard for physicists.
Best regards. ... Al
Al Vilcius
Campbellville, ON, Canada

7:05 AM  

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