Nuclear Decay May Vary With Earth-Sun Distance

KentuckyFC writes "We've long thought that nuclear decay rates are constant regardless of ambient conditions (except in a few special cases where beta decay can be influenced by powerful electric fields). So that makes it hard to explain two puzzling experiments from the 1980s that found periodic variations over many years in the decay rates of silicon-32 and radium-226. Now a new analysis of the raw data says that changes in the decay rate are synchronized with each other and with Earth's distance from the sun. The physicists behind this work offer two theories to explain why this might be happening (abstract). First, some theorists think the sun produces a field that changes the value of the fine structure constant on Earth as its distance from the sun varies. That would certainly affect the rate of nuclear decay. Another idea is that the effect is caused by some kind of interaction with the neutrino flux from the sun's interior which also varies with distance. Take your pick. What makes the whole story even more intriguing is that for years physicists have disagreed over the decay rates of several isotopes such as titanium-44, silicon-32, and cesium-137. Perhaps they took their data at different times of the year?"

Comments

Carbon Dating

[Jaysyn]

Does this have any ramifications for carbon dating?

Re:Carbon Dating

[Bob-taro]

Also, it is only these two isotopes that are mentioned, presumably because most other isotopes tested do not have this sort of periodic effect.

I wouldn't presume that. The very thing that makes this so interesting is that "the modulations are synchronised with each other and with Earth's distance from the sun." To me, that makes it likely to be a general effect on all radioactive materials. I don't know if this will lead to anything that supports a young earth theory, but it'll be interesting to see what comes from it. The article also mentions:

It turns out, that the notion of that nuclear decay rates are constant has been under attack for some time. In 2006, Jenkins says the decay rate of manganese-54 in their lab decreased dramtically during a solar flare on 13 December.

This is a good example of how many holes there might be in our theories about the universe. We have been making measurements for a few 1000 years in one solar system (mostly just on one planet) and things that we don't see changing, like radioactive decay rates, we consider constant. It's exciting to think how much more there may still be to discover.

Re:Carbon Dating

[es330td]

I'm more interested to know if this has any impact on nuclear waste. If decay can be sped up artificially one of the biggest objection points against widescale adoption of nuclear power in the US goes away.

Re:Carbon Dating

[fatphil]

Take an old vinyl record. Punch a new hole just off-centre. Play the record. Sometimes it's too high pitched (fast) and sometimes it's too low pitched (slow). Yet the song still takes the same length of time to play.

I.e. no.

Re:Carbon Dating

[Scott Carnahan]

It does take a very long time for this to happen - geologic time - but even a "long time" is not forever.

The idea that a diamond will decay into graphite in geologic time is a popular fiction. The activation energy barrier for the diamond-graphite transition is high enough that substantial decay at STP will take far longer than the Earth will last, and the time scale is therefore not geologic. Several samples of diamond have been found that crystallized before the formation of the solar system, and some carbonados exhibit Xenon isotope concentrations in inclusions that suggest that they formed in distant supernovas and fell to earth.

Fine structure constant

[kmac06]

One possible explanation proposed in this paper is:

In their theory, the Sun produces a scalar field which would modulate the terrestrial value of the electromagnetic fine structure constant EM.

The fine structure constant (about 1/137) has been measured to a whopping 10 significant digits, one of the most precisely measure physical constants. If there is a seasonal variation enough to influence decay rates by .1%, wouldn't this show up in different experiments measuring the fine structure constant?

One possible explanation

[elrond2003]

As someone who made the equipment that the scientist probably used to do the counting, I have one possible explanation. Most Multichannel Analyzers (MCAs) of the time used a line clock to determine the time. They assume that the power company delivered 60Hz power (or 50 Hz in Europe), This frequency was almost never precise but varied by .1 to .2% (one plant where I measured the frequency put out 58.8Hz for example, a real mess for us) from time to time. A systemic variation due to power loads (heating in winter/ AC in summer) could easily bias the power frequency by about the right amount with the right periodicity. The universe might well be safe.