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Sun's Activity Levels Reconstructed
neutron_p writes "An international team of scientists has reconstructed the Sun's activity over the last 11 millennia and forecasts decreased activity within a few decades. The activity of the Sun over the last 11,400 years, i.e., back to the end of the last ice age on Earth, has now for the first time been reconstructed quantitatively. The scientists have analyzed the radioactive isotopes in trees that lived thousands of years ago. As scientists report in the current issue of the science journal Nature, one needs to go back over 8,000 years in order to find a time when the Sun was, on average, as active as in the last 60 years."
In order to investigate the issue, NASA has announced that they are sending an unmanned space probe to the sun. In order to avoid the intense heat, they are planning on launching the probe at night.
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I'm not sure I trust their error bars (they appear on the second plot). Since they're using 10-year averages, they should be removing the effects of the solar cycle. But their sunspot number curves drop below 0 sunspots in several places. A negative number of sunspots is, obviously, unphysical. Also, their data is pretty wildly varying over short timescales (again, solar cycle should be removed) and doesn't match the actual sunspot records from 1610 on very well, either.
They've been around for so long and their Java-Interpreter is still not... Oh, wait, you mean that other sun, don't you?
One thing I'm curious about is what effect that the Sun's activity has on climate change. There have been spacecraft studying the sun and more spacecraft studying the magnetosphere and it's interaction with the solar wind. However, it seems that we only have understanding of individual events and the immediate effects of those events. It will be really interesting when some people get a good idea of what long term effects CMEs (coronal mass ejections) and other Sun activity has on our little blue world.
I wonder if instead of just examining the historical record, they also took one additional factor into account.
Physicists modelling the history of the Sun say that its overall brightness (read: activity level) has increased by about 30% since being born. This is related to the buildup of helium "ash" (from fusion of hydrogen) in its core. Furthermore, the trend is expected to continue -- quite slowly, of course. Nevertheless, any forcast that the current activity can be expected to decrease in the next few years -- or even decades -- might be rather "off" if that factor is not taken into account....
So... we'll schedule the Global Cooling panic for what, 2030-ish? That good for everyone?
Save your Global Cooling books from the 70s, they'll be invaluable in showing how long it has been a problem even as the Global Warming hysteria is quietly, but thoroughly, whitewashed out of existance (just as the Global Cooling panic has been, as of today).
See you then!
(This is about 1/3 humorous, 1/3 a troll, and 1/3 an attempt to get people to be a little less dogmatic and a little more thoughful about climate issues in general. Moderate accordingly, I guess.)
(PS: I would expect the Earth's temp, if it is affected significantly by the Sun, to lag behind it by several years, because it has one hell of a lot of "thermal inertia".)
The temperature variations have been tracked over centuries using heat-flow measurements in boreholes.
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The Sun is approximately 4.5 billion years old. An increase in the average brightness of 30% over that time is equal to 6.7% per billion years, or .00000067% per century. If you think that this will become a measurable change in the next century, you obviously never learned anything worthwhile from a lab course (and nobody should trust you with numerical methods, either).
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You mean this part?Emphasis mine. It does not say anything about whether the activity can account for the temperature. In fact, it quite explicitly disclaims any such claims in either direction. It is too soon. You need to brush up on your science skills, and your ability to read what things say instead of reading what you want them to say. If more climate fearmongers demonstrated these skills, I might actually be willing to join them in their panic. But dogma, dogma, dogma, and carefully selected evidence seems to rule the day.
Less dogma, more science, please.
Here's another article that talks a little more about the findings, including a very short discussion on possible implications regarding climate change and global warming. Although a correlation makes sense and there appears to be a link between global climate change and sunspots in several instances, there is not enough data to be conclusive and the current warming trends do coincide with increasing levels of methane and CO2. It could be either or both.
In addition to the obvious question of whether this affects our climate, the findings are interesting simply because they provide more information about our sun. I think it's amazing we can look at carbon-14 content here on earth an make inferences about the solar weather 10000 years ago. They're using this to show indirectly that the sun exhibits it's own long term "climate changes" as expected. Of course, other bodies do this as well. For example, that hurricane on Jupiter (the red spot) that's been hanging around for just a little bit longer than Frances.
If you go searching for data on borehole temperature measurements, you'll find that annual temperature cycles are measurable for some years as they propagate into the earth. It's true to a degree that "the temperature is always the same underground", but only to a degree; think about what "frost line" means for an example.
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