The discussion revolves around the implications of a potentially changing speed of light on the permittivity and permeability of vacuum. Participants explore whether these quantities are constants that can be derived or if they are solely based on experimental measurements. The conversation touches on theoretical considerations, experimental data, and the relationship between these physical constants.
Participants express differing views on whether the speed of light is changing and its implications for permittivity and permeability. There is no consensus on the derivability of these constants or the interpretation of the fine structure constant.
Some claims depend on specific definitions and systems of units, and the discussion includes unresolved questions about the implications of experimental findings on theoretical models.
iScience said:If the speed of light is changing, does this mean that the permattivity and/or permeability are dynamically changing quantities? are these "constants" derivable yet or are they still only experimentally measured quantities?
The speed of light, vacuum permettivity and vacuum permeability are all determined by the system of units. In natural units they are all equal to 1, and in CGS the vacuum permeability and permittivity do not even exist.iScience said:If the speed of light is changing, does this mean that the permattivity and/or permeability are dynamically changing quantities? are these "constants" derivable yet or are they still only experimentally measured quantities?
Now, Lamoreaux, along with LANL colleague Justin Torgerson, has re-analysed the Oklo data using what he says are more realistic figures for the energy spectrum of the neutrons present in the reactor. The results have surprised him. Alpha, it seems, has decreased by more than 4.5 parts in 108 since Oklo was live (Physical Review D, vol 69, p121701).
That translates into a very small increase in the speed of light (assuming no change in the other constants that alpha depends on), but Lamoreaux's new analysis is so precise that he can rule out the possibility of zero change in the speed of light. "It's pretty exciting," he says.
What makes you think the speed of light (in vacuum) is changing?
The speed of light, vacuum permettivity and vacuum permeability are all determined by the system of units. In natural units they are all equal to 1, and in CGS the vacuum permeability and permittivity do not even exist.