User:Brews ohare/Physchim62: A typical discussion
A verbatim dialog with Physchim62 illustrating a failure to follow simple discussion:
- One is free to measure the separation of two points A & B in wavelengths or in transit times at two different times t1 and again at time t2. If, for example, the two wavelength measurements agree and the two times-of-transit disagree, one needs an explanation. For example, perhaps the speed of light c (the one in relativity) changed. Other explanations are possible. However, of course, regardless of the explanation finally adopted, regardless of whether c is determined to have changed, c0 (the one in SI Units) has not changed. Brews ohare (talk) 15:26, 19 October 2009 (UTC)
- There is no CGPM speed of light: there is an SI metre. That is one length standard you can use to measure physical phenomena, a length standard which is super for dealing with human-scale lengths on the surface of the Earth. If you want to deal with lengths that are very much smaller or very much larger than the human scale, or if you are not restricted to the surface of the Earth as your place of measurement, you might find it useful to use different length standards: astronomers and crystallographers have done that for as long as both scientific disciplines have existed. Physchim62 (talk) 15:48, 19 October 2009 (UTC)
- And your point? Maybe it is the same as my point: the speed of light (the one in relativity) c and the SI units c0 (the "speed of light" in SI units) are distinct from one another. One can be measured (c) and the other is 299 792 458 m/s (c0) "now a defined constant, not to be measured again." Brews ohare (talk) 16:41, 19 October 2009 (UTC)
- I view it differently, as you might imagine! For a start, c0 would be the the speed in relativity, and c would be the observed speed of light, that goes from a simple correlation with other standard forms. More importantly, there is absolutely no evidence that they are different. If such evidence comes to light, it would require much more than a splitting of the two articles on Wikipedia but, for the time being, there is NONE! Physchim62 (talk) 16:52, 19 October 2009 (UTC)
- The notation c0 is reserved for the SI Units number 299 792 458 m/s, as you well know. That is the same number described by Sullivan as "now a defined constant, not to be measured again." On the other hand, c, the speed in relativity, can be and is being measured all the time as part of the exploration of cosmological theories about the expansion of space and in the exploration of quantum gravity. Brews ohare (talk) 17:04, 19 October 2009 (UTC)
- Not unless you believe in the Global Conspiracy… Physchim62 (talk) 17:07, 19 October 2009 (UTC)
- The notation c0 is reserved for the SI Units number 299 792 458 m/s, as you well know. That is the same number described by Sullivan as "now a defined constant, not to be measured again." On the other hand, c, the speed in relativity, can be and is being measured all the time as part of the exploration of cosmological theories about the expansion of space and in the exploration of quantum gravity. Brews ohare (talk) 17:04, 19 October 2009 (UTC)
- I view it differently, as you might imagine! For a start, c0 would be the the speed in relativity, and c would be the observed speed of light, that goes from a simple correlation with other standard forms. More importantly, there is absolutely no evidence that they are different. If such evidence comes to light, it would require much more than a splitting of the two articles on Wikipedia but, for the time being, there is NONE! Physchim62 (talk) 16:52, 19 October 2009 (UTC)
- And your point? Maybe it is the same as my point: the speed of light (the one in relativity) c and the SI units c0 (the "speed of light" in SI units) are distinct from one another. One can be measured (c) and the other is 299 792 458 m/s (c0) "now a defined constant, not to be measured again." Brews ohare (talk) 16:41, 19 October 2009 (UTC)
- There is no CGPM speed of light: there is an SI metre. That is one length standard you can use to measure physical phenomena, a length standard which is super for dealing with human-scale lengths on the surface of the Earth. If you want to deal with lengths that are very much smaller or very much larger than the human scale, or if you are not restricted to the surface of the Earth as your place of measurement, you might find it useful to use different length standards: astronomers and crystallographers have done that for as long as both scientific disciplines have existed. Physchim62 (talk) 15:48, 19 October 2009 (UTC)