Fine-structure constant: Difference between revisions

Content deleted Content added
CATion1248 (talk | contribs)
Measurement: Mention of magnetic constant
Undid revision 1308068403 by Papybare (talk): obscure proposals by one guy aren't suitable for inclusion here, even if they technically made it through peer review somewhere (in other words, surviving peer review is the first step, not the last)
 
(13 intermediate revisions by 6 users not shown)
Line 404:
In the experiments below, {{math|Δ''α''}} represents the change in {{mvar|α}} over time, which can be computed by {{mvar|α}}<sub>prev</sub> − {{mvar|α}}<sub>now</sub>&nbsp;. If the fine-structure constant really is a constant, then any experiment should show that
<math display="block">\frac{\ \Delta \alpha\ }{\alpha} ~~ \overset{\underset{\mathsf{~def~}}{}}{=} ~~ \frac{\ \alpha _\mathrm{prev}-\alpha _\mathrm{now}\ }{\alpha_\mathrm{now}} ~~=~~ 0 ~,</math>
or as close to zero as experiment can measure. Any value far away from zero would indicate that {{mvar|α}} does change over time. So far, most experimental data is consistent with {{mvar|α}} being constant, up to 10 digits of accuracy.
 
=== Past rate of change ===
Line 780:
 
== Anthropic explanation ==
The [[anthropic principle]] isprovides an argument aboutas to the reason the fine-structure constant has the value it does: stable matter, and therefore life and intelligent beings, could not exist if its value were very different. One example isFor thatinstance, if modern grand unified theories are correct, then {{mvar|α}} needs to be between around 1/180 and 1/85 to have proton decay to be slow enough for life to be possible.<ref>
{{cite journal
|last=Barrow |first=John D.