As I understand it the uranium from the oklo reactor showed us that decay rates have been constant over billions of years. This is because if decay rates had changed then alpha the fine structure constant which measures electromagnetic force would have had to have changed as well. If alpha had changed then the point at which critical mass was reached to enable fusion to occur would have been different , but indications from Oklo are that fusion was reached at the same point as today, therefore alpha was the same?
Is this correct....anyone know?
[This message has been edited by judge, 12-08-2003]
It is usually claimed that Oklo sets limits on how much the fine structure constant - designated as the symbol alpha (and which is itself a mathematical combination of other constants) - could have been different than its present value, at the time the Oklo reactors were reacting.
The argument goes something like this: Samarium-149 is produced by fission. It has a neutron absorption resonance that is close to the thermal energy of the neutrons in the reactors. It is theorized that a change in the fine structure constant (alpha) would cause a shift in the resonance energy level of Sm-149 which would be detectable by the isotopic content that we can measure today. It’s not really related to critical mass (only distantly, if at all). If I run across a reference that explains it more clearly, I’ll post it (I think I've seen one). By the way, the spectra of quasars is currently thought to show that the fine structure constant has changed, this may or may not contradict the Oklo results – this is covered in one of the links above.
Interestingly, there is a paper in the Proceedings of the Fifth International Conference on Creationism, that makes the case that Oklo seems to be indicating that one or more nuclear constants must have been fairly drastically different when Oklo was reacting. The argument goes like this: Some (most?) of the reactors at Oklo were too thin, by a long shot, to go critical (oddly, this problem is something you don’t see mentioned in the popular literature on Oklo, nor in most all of the technical literature). Yet there is evidence of criticality. How can this be? The only way some of the reactors at Oklo could have been reactors is if some of the nuclear properties of some, or all, of the isotopes involved were different when the reactors were critical.
[This message has been edited by Turtle, 12-11-2003]
The quasar results are currently hotly debated in the astrophysics community. Most astrophysicists are doubtful of the claims. The experimental technique being used is extremely difficult to perform and very susceptible to errors.
I know in my department the observational guys think it's a false result.