Trees grow faster during periods of greater cosmic radiation from the sun:
During a number of years, the trees’ growth also particularly slowed. These years correlated with periods when a relatively low level of cosmic rays reached the Earth’s surface. When the intensity of cosmic rays reaching the Earth’s surface was higher, the rate of tree growth was faster. . .
Cosmic rays are actually energetic particles, mainly protons, as well as electrons and the nuclei of helium atoms, that stream through space before hitting the Earth’s atmosphere. The levels of cosmic rays reaching the Earth go up and down according to the activity of the Sun, which follows an 11-year cycle.
As someone pointed out, this may be another example of radiation hormesis. Although some examples of hormesis may be due to immune-system stimulation, you can also see hormesis with single cells, which don’t have an immune system, of course. They do have repair mechanisms.
From my point of view this is interesting because it helps to show what a big effect hormesis is. I’m sure we need daily stimulation of our repair systems to be our healthiest but this isn’t a part of standard teaching about health. It goes against what people are usually taught (e.g., all germs are bad, all air pollution is bad, keep from getting sick by avoiding contagion) roughly as much as does the Shangri-La Diet. The scientists who discovered the tree effect appear to not know about hormesis (“As for the mechanism, we are puzzled”).
The success of the Shangri-La Diet teaches that the obesity epidemic is due to eating too much food that has exactly the same flavor (smell) each time — from one can of Coke to the next, for example. In practice, this too-constant food is food from a package (food made in a factory) and food from a restaurant. My umami hypothesis says that the epidemic of autoimmune diseases has the same source. Food in a package is more sterile than other food because bacteria reduce shelf life so preservatives are added and/or manufacturing steps (e.g., pasteurization) kill bacteria. Food from a restaurant has usually been freshly cooked (killing bacteria) and all sorts of precautions (“food safety”) are taken to make sure it remains low in bacteria.
Thanks to David Cramer.
Sorry, Seth, this is BS. Yes, there is a correlation between cosmic radiation exposure and tree growth. There’s also a correlation between sunspots and tree growth, and between tree growth and hemlines. Might tree growth control hemlines? Might tree growth control the sunspot cycle?
It will take enormously more evidence to demonstrate any connection whatsoever between this phenomenon and radiation hormesis. All we can say now is that such an effect may be possible, but we could just as well have said so before, with just as much reason.
Do you wonder why we say you’re not the go-to guy on causation?
Nathan, I don’t know what you mean by “this correlation is BS”. Nor do I have any idea why you believe this.
Hormesis is not the only possible explanation of the correlation. Another could be found in the book The Chilling Stars
https://www.amazon.com/Chilling-Stars-2nd-Cosmic-Climate/dp/1840468661/ref=sr_1_1?ie=UTF8&s=books&qid=1256087000&sr=8-1
The authors claim that cosmic radiation affects the amount of cloud cover over the earth, which in turn affects global temperatures. This could have an effect on the growth rate of trees.
The correlation is not BS. The causative chain leading you to radiation hormesis, though, is stage after stage of pure speculation, what Simon Singh got in trouble in the UK for calling “bogus”.
That doesn’t mean our immune systems don’t need frequent jostling, or that we don’t benefit from fomenting population battles among our gut flora, which might not be the same thing. It just has nothing demonstrable to do with them.
Confirmation bias isn’t your friend. Aaron, I expect you’ve explained this to Seth before.
Nathan, you say “the causative chain leading [me] to radiation hormesis is stage after stage of pure speculation.” It was someone else’s idea, not mine, that this result could be explained by radiation hormesis. The pure speculation here is your description of their reasoning. There is something to what you say, in the sense that bacteria (found in fermented food) are highly unlikely to damage cells the same way cosmic rays or other radiation does. The value of hormesis for my argument isn’t that the mechanism is exactly the same (bacteria work outside cells, stimulating the immune system; at least some hormesis has an intracellular explanation) but that hormesis makes the general point that biological repair systems can benefit from a low level of damage, because it stimulates them.
Tom, yes it certainly isn’t the only explanation proposed. For me the interesting question is whether the dosages match up — whether the cosmic radiation dose is similar to the dosages that produce hormesis under laboratory conditions. Hormesis is obtained under a narrow range of dosages — too little and there’s no effect, too much and the cell or plant or whatever is harmed.