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Author Topic:   Different Radioactive-Decay Mechanisms
lpetrich
Inactive Member


Message 1 of 2 (32855)
02-22-2003 2:17 AM


This is a serious problem for the young-earth-creationist hypothesis of variable decay rates. Why should they vary by a factor of a million in such exact proportion?
This is an especially serious problem when one considers that long-lived nuclides decay by different mechanisms.
Alpha-like:
Alpha decay (release of helium-4 nucleus)
Spontaneous fission
Beta-like:
Beta decay (release of an electron or a positron)
Electron capture
Alpha-like decays are nonrelativistic, and they proceed by quantum-mechanical barrier penetration. Follow the result nuclei backward, and because of electrostatic repulsion, they will stop before they touch. However, they have wave as well as particle properties, meaning that their positions are slightly uncertain -- enough to travel through the electrostatic-potential barrier and touch each other.
Beta-like decays are relativistic; electrons and positrons are usually emitted at close to the speed of light in a vacuum, c, and (anti)neutrinos are emitted at very close to that speed. These happen as a result of the charged weak interaction. A neutron turns into a proton and a virtual W-, which in turn produces an electron and an antineutrino. Or a proton turns into a neutron and a virtual W+, which in turn produces a positron and a neutrino. Or that W+ combines with with a nearby electron, producing that neutrino. And these reactions are slowed by the W particle having a mass about 90 times that of a nucleon.
Both alpha-like and beta-like decays happen faster with more energy available, but they have very different energy dependencies. For available energy E:
For alpha-like decays, the rate ~ exp(- sqrt(Eb/E)) where Eb is the barrier-penetration energy.
For beta decays proper, the rate ~ E^5 (e+ or e- is relativistic) or ~ E^(7/2) (e+ or e- is nonrelativistic)
For electron captures, the rate is ~ E^2.
I won't go any further, but suffice it to say that alpha-like and beta-like decays have other differences in their dependence on various fundamental-constant values. Which makes lockstep variation extremely implausible.

Replies to this message:
 Message 2 by Joe Meert, posted 02-22-2003 9:38 AM lpetrich has not replied

  
Joe Meert
Member (Idle past 5680 days)
Posts: 913
From: Gainesville
Joined: 03-02-2002


Message 2 of 2 (32867)
02-22-2003 9:38 AM
Reply to: Message 1 by lpetrich
02-22-2003 2:17 AM


not to mention
The incredible heat buildup
ROASTING ADAM-Creationism's Heat Problem
Cheers
Joe Meert

This message is a reply to:
 Message 1 by lpetrich, posted 02-22-2003 2:17 AM lpetrich has not replied

  
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