# Sun can alter radioactive decay rates?? **URL:** \ **Category:** Factual Questions\ **Created:** [November 13, 2008, 11:11pm UTC](https://boards.straightdope.com/t/sun-can-alter-radioactive-decay-rates/472614 "2008-11-13T23:11:57Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [November 13, 2008, 11:11pm UTC](https://boards.straightdope.com/t/sun-can-alter-radioactive-decay-rates/472614/1 "2008-11-13T23:11:57Z")
[Evidence for Correlations Between Nuclear Decay Rates and Earth-Sun Distance](http://arxiv.org/PS_cache/arxiv/pdf/0808/0808.3283v1.pdf) Is this (A.) asshattery (B.) legitimate but almost certainly mistaken, or (C.) something truly incredible? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [November 13, 2008, 11:38pm UTC](https://boards.straightdope.com/t/sun-can-alter-radioactive-decay-rates/472614/2 "2008-11-13T23:38:17Z")
[The mystery of the varying nuclear decay](http://physicsworld.com/cws/article/news/36108) > [@](#): > > an experiment performed at Brookhaven National Laboratory (BNL), New York, between 1982 and 1986. The BNL team found that over that period the decay constant of silicon–32 — relative to a long-lived standard — modulated around its usual value of about 172 years by the order of 0.1%. What is more, the modulation appeared to be almost in phase with the varying distance of the Earth to the Sun The current researchers claim a correlation between solar flares and the decay rate of manganese–54. The data (see fig in link) is not very impressively correlated to solar activity. That said, _something_ does seem to be happening. ---
**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\ **Post date:** [November 13, 2008, 11:44pm UTC](https://boards.straightdope.com/t/sun-can-alter-radioactive-decay-rates/472614/3 "2008-11-13T23:44:30Z")
Some sort of correlation is there, but my guess is that they will eventually find that their measurement depends on temperature or barometric pressure or total daylight or snowfall or university steam usage or _something_ that itself has a correlation with the Sun-Earth distance. If I remember later, I’ll take a look at their paper to see if I can make an educated guess as to what their particular apparatus might be sensitive to. ---
**Author:** ![Half\_Man\_Half\_Wit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/half_man_half_wit/32/21766_2.png) [@Half\_Man\_Half\_Wit](https://boards.straightdope.com/u/Half_Man_Half_Wit)\ **Post date:** [November 13, 2008, 11:45pm UTC](https://boards.straightdope.com/t/sun-can-alter-radioactive-decay-rates/472614/4 "2008-11-13T23:45:01Z")
Whatever happens apparently doesn’t happen to all radioactive decays – the Pu-238 on board of the Cassini spacecraft doesn’t show any correlation of decay rate and solar distance, as per [this paper](http://arxiv.org/abs/0809.4248). ---
**Author:** ![bonzer](https://avatars.discourse-cdn.com/v4/letter/b/45deac/32.png) [@bonzer](https://boards.straightdope.com/u/bonzer)\ **Post date:** [November 13, 2008, 11:59pm UTC](https://boards.straightdope.com/t/sun-can-alter-radioactive-decay-rates/472614/5 "2008-11-13T23:59:59Z")
As regards the Brookhaven claim, to echo **Pasta** , suggestions of small, controversial effects that happen to have the period of exactly a year tend to give physicists the heebie-geebies. Also, it’s hardly encouraging that it’s now being pushed by Ephraim Fischbach. The old “fifth force” controversy he triggered saw some interesting research done, but people were also privately saying some brutal stuff about his original paper from the start.