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The Sun's Odd Behavior
gyrogeerloose writes "Most of us know about the sun's eleven-year activity cycle. However, relatively few other than scientists (and amateur radio operators) are aware that the current solar minimum has lasted much longer than expected. The last solar cycle, Cycle 24, bottomed out in 2008, and Cycle 25 should be well on its way towards maximum by now, but the sun has remained unusually quiescent with very few sunspots. While solar physicists agree that this is odd, the explanation remains elusive."
I almost know nothing on the subject, but I'm thinking the 11 year cycle was empiricaly determined. One has to wonder do we have enough data on the subject compared to the age of the sun?
On the one hand, outside the kind of geeky population represented by slashdot, I really doubt a lot of people know about the 11 year cycle. On the other hand, I've seen othee articles about the recent abnormally low period, and the subect also seems to come up frequently on the recurring global warming debate that seems to crop up in every third article. (Which isn't to say that more information about the subject isn't wanted of course.)
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Seriously though; supposing (just because we're being crazy and ridiculous) that global warming is happening, wouldn't it be a concern that the next solar cycle will be starting later, reducing only the short-term effects of a problem that is only significant in the long-term (and without delaying/decreasing those long-term effects)?
Put another way: Supposing the temperature is going to be X degrees higher by 2YYY, wouldn't it be much better for the increase to be steady and predictable?
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Not to break off this delightful train of thought, but the problem is that the sun is getting cooler. A lot cooler. It's magnetic field is looking dismal. It hasn't thrown a single plane even slightly off course for years, when predictions were it should have caused at least a few disasters by now (at it's higher intensities it can block radio communcations for weeks, make every compass useless (including ill-shielded gyroscopic ones, so it can even make the instruments in older planes miss where the ground is. Confused instruments and the resulting panicking pilots do not make for safe air traffic), and in simulations it has destroyed every electricity grid on the planet in a matter of seconds). And every day it is cooling and weakening a bit more (this "bit" more meaning you could power Al Gore's electricity bill for a billion years with the "bit" of power that it loses in a nanosecond). It's not yet "oh no it's the end of the world" solar cooling, ... but it's confusing and if it doesn't stop, it won't be long for that.
And while everyone fully expects the sun to start it's next cycle any second now (it hasn't for 1.5 years now, only a few pathetic false starts), if for any reason it doesn't do so soon there won't be any more global warming for 2010-2020 than there was for 2000-2010, or it might even cool significantly more. And while global warming, in the worst cases, displaces a few coastal cities and makes jungles the size of continents out of deserts (esp. in conjunction with rising co2 levels), global cooling does indeed the reverse (deserts are created by cold, not warm, weather, and the process is sped up by low concentrations of co2 (today's "alarming" concentrations of co2 are still in the "I'd like 10 times that, please" level where plants are concerned)).
Needless to say, the IPCC's predictions are entirely dependant on the assumption that you could correct cesium clocks by checking the solar cycle.
If you want a solar story that adds a bit more mystery to the rehash of the current solar tale in the linked article, google up Livingston and Penn about the observations that the sunspot frequency is diminishing. In the past, the solar flux would match up to the sunspot number closely. Beginning some twenty some odd years ago, this century long curve matching parted ways. To sum up the mystery, in ten years time, solar cycles will continue. It's just there won't be any more sunspots. (a little hyperbole, but not as much as you think)
One of my hobbies is meteorology and as I'm in the UK there's no shortage of discussion about the weather!
Over on the various weather forums we've been discussing the solar minimum for the past couple of years, as in the UK at least there's a strong correlation between climatic cold spells and low sunspot activity (the Little Ice Age a few hundred years ago coincided with the Maunder minimum, for example). There was another minimum in the early 1800s, again coinciding with a colder period in the UK climate. It was during this time that Charles Dickens popularised the idea of a White Christmas, something which hasn't occured in 40 years here (30 miles east of London).
The effects are pretty immediate in climating terms, with an onset of years rather than decades. Although yes, the Sun's becoming more active there's been a lot of discussion as to whether the low solar activity was responsible for the coldest winter in 17 years in England (and longer than that in Scotland).
The Sun's effect on the climate is probably beyond any numerical weather prediction models at the moment but it'd be fascinating to see what the effects would be if we were to experience a prolonged period of much lower solar activity than normal!
How do you know that U235 and U238 are produced in roughly equal abundance? This is not generally true of isotopes of other elements. I'm a little doubtful that the production rates can be derived accurately enough from theory to produce a useful age limit.
The amount of helium in the Sun provides a limit on the total energy it has radiated, assuming we're right about how fusion works. Combine that with the observed total radiation of the Sun and you can get what I think is a better crude limit on the Sun's age. You can do better by dating certain meteorites, which appear to have been created at about the same time as the Sun.
a,e,i,o,u and sometimes w and y (at be if of up cwm by)