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- Path: sparky!uunet!news.claremont.edu!nntp-server.caltech.edu!brahm
- From: brahm@cco.caltech.edu (David E. Brahm)
- Newsgroups: sci.physics
- Subject: Re: Some physics questions
- Date: 7 Nov 1992 09:28:15 GMT
- Organization: California Institute of Technology, Pasadena
- Lines: 27
- Distribution: na
- Message-ID: <1dg27fINNihp@gap.caltech.edu>
- References: <5NOV199211284285@csa2.lbl.gov> <1992Nov6.175022.13136@galois.mit.edu> <6NOV199212364099@csa1.lbl.gov>
- NNTP-Posting-Host: punisher.caltech.edu
- Summary: Dimensionful vs. dimensionless constants
-
- sichase@csa1.lbl.gov (SCOTT I CHASE) writes:
- > What makes the speed of light any more fundamental than the charge
- > of an electron, or the electroweak mixing angle?
-
- Forgive me for jumping into a thread I haven't followed, but the obvious
- answer is that the speed of light has *dimensions*, and thus is determined
- by (or *defines*) the units you work in. Once you set up (Planck) units
- where c=G=hbar=1, the remaining physical constants (the dimensionless ones)
- are the interesting ones.
-
- For example, m(electron)/M(Planck) = 10^-22 might be the product of (a)
- a SUSY-or technicolor-breaking scale, which in turn comes from the
- logarithmic running of some coupling constant, and (b) some Yukawa
- coupling.
-
- > And even if it's more fundamental, what prevents you, in principle,
- > from developing a theory which predicts the speed of light?
-
- That theory would have to predict the length of a certain bar in Paris and
- the rotational rate of a certain small (but nice) planet.
-
- --
- Staccato signals of constant information, | David Brahm, physicist
- A loose affiliation of millionaires and | (brahm@cco.caltech.edu)
- billionaires and Baby ... |---- Carpe Post Meridiem! --
- These are the days of miracle and wonder, | Disclaimer: I only speak
- And don't cry, Baby, don't cry, don't cry. | for the sensible folks.
-