Re: Curiosity and skepticism to reports that the sun causes variations in the decay rates of some isotopes

Adam wrote:
On 24 Nov 2008 09:28:37 GMT, Richard Tobin wrote:

In article <6n2ki4ljo2kksfr4m5nbtdftkvs8anijkr@xxxxxxx>,
Adam <no@xxxxxxxx> wrote:

If the rate of change were immutable, wouldn't that rule out nuclear
power plants, where the rate at which the fuel "changes into another
isotope or element" via fission is /controlled/?

It's the rate of *spontaneous* decay that is believed to be constant.
In a reactor, nucleii decay because they are hit by neutrons from
other decays.

Understood.

But spontaneous decay takes place in an environment.

The decay inside a reactor is also "spontaneous" -- but in a much
"hotter" environment.

While the isolated fuel nuclei have an constant half life, fission
can also be triggered by the nucleus absorbing the energy from a
slow neutron. In this sense it is not spontaneous, but triggered.


One half-life ago, the amount of radiation emitted by all the element
X in the world was twice what it is now.

Ditto element Y for its half-life, etc.

It would seem that there were more neutrons floating around 4 billion
years ago. Perhaps the half-lives for "spontaneous" decay in that
"warmer" environment were shorter?

Fission decay products are not just neutrons; In many cases they
are long-lived nuclei. Alpha decays produce helium nuclei.

Neutrons don't "float around". They get absorbed or decay. Half life
of a free neutron is about 15 minutes.


.

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