Saturday, September 11, 2010

Radioactive decay isn't constant

This post is partly made to be an extension of my memory.

I find this fascinating: Radioactive decay rates vary with the sun's rotation:

A team of scientists from Purdue and Stanford universities has found that the decay of radioactive isotopes fluctuates in synch with the rotation of the sun's core.
The fluctuations appear to be very small but could lead to predictive tools for solar flares and may have an impact on medical radiation treatments.
This adds to evidence of swings in decay rates in response to solar activity and the distance between the Earth and the sun that Purdue researchers Ephraim Fischbach, a professor of physics, and Jere Jenkins, a nuclear engineer, have been gathering for the last four years. The Purdue team previously reported observing a drop in the rate of decay that began a day and half before and peaked during the December 2006 solar flare and an annual fluctuation that appeared to be based on the Earth's orbit of, and changing distance from, the sun, Jenkins said.


The assumption has always been that radioactive decay never varied; it was always constant. This affects things like atomic clocks and estimates on the age of artifacts.

Right now scientists only see a slight variation, like one tenth of one percent. So it may not make a huge difference.

I find it exciting that there is still much of the universe we don't understand.


Anonymous said...

So Winchell D. Chung mentioned this too, and the best possible use for this is for astronauts to predict and evade solar storms that would otherwise cause them great harm. This seems to work because the decay rate changes a day or two before solar output changes.

Henry Cate said...

An early warning system for solar storms will be a great benefit as we move more into space.

I wonder what it is about solar activity that influences radioactive decay. Does this mean materials decay faster when they are close to the sun, and slower out say near Pluto?

My father speculated that the flow of neutrinos might sometimes cause the decay.

Anonymous said...

Yeah, I sort of remember from watching Nigel Calder's "Key to the Universe" that neutrinos are the gauge particles for the weak force, and the weak force is responsible for radioactive decay.

Anonymous said...

I guess I didn't "sort of remember" correctly; that's not what the show said.