Posted on 01/25/2007 4:40:59 PM PST by blam
Sun's fickle heart may leave us cold
25 January 2007
From New Scientist Print Edition.Stuart Clark
There's a dimmer switch inside the sun that causes its brightness to rise and fall on timescales of around 100,000 years - exactly the same period as between ice ages on Earth. So says a physicist who has created a computer model of our star's core.
Robert Ehrlich of George Mason University in Fairfax, Virginia, modelled the effect of temperature fluctuations in the sun's interior. According to the standard view, the temperature of the sun's core is held constant by the opposing pressures of gravity and nuclear fusion. However, Ehrlich believed that slight variations should be possible.
He took as his starting point the work of Attila Grandpierre of the Konkoly Observatory of the Hungarian Academy of Sciences. In 2005, Grandpierre and a collaborator, Gábor Ágoston, calculated that magnetic fields in the sun's core could produce small instabilities in the solar plasma. These instabilities would induce localised oscillations in temperature.
Ehrlich's model shows that whilst most of these oscillations cancel each other out, some reinforce one another and become long-lived temperature variations. The favoured frequencies allow the sun's core temperature to oscillate around its average temperature of 13.6 million kelvin in cycles lasting either 100,000 or 41,000 years. Ehrlich says that random interactions within the sun's magnetic field could flip the fluctuations from one cycle length to the other.
These two timescales are instantly recognisable to anyone familiar with Earth's ice ages: for the past million years, ice ages have occurred roughly every 100,000 years. Before that, they occurred roughly every 41,000 years.
Most scientists believe that the ice ages are the result of subtle changes in Earth's orbit, known as the Milankovitch cycles.
(Excerpt) Read more at environment.newscientist.com ...
Big Rock
Attila is apparently a common name in Hungary, since the original Attila used the country for his base camp. I'm a little more skeptical of the "Grandpierre" part.
Atilla Grandpierre. That's Atilla the big Peter.
more oxygen, and consuming more CO2.
There was a mini-Ice Age that lasted from around 1400 until the mid-19th century.
Snowshoes are a good thing....
:')
And also more chlorophyl -- which ultimately is the food of all living organisms here on earth. (I.e., animals eat plants, humans eat plants and animals....)
Attila Grandpierre..... we could call him "Attila the Hung."
And these in turn serve as causes for other forms of complex activity on the Sun which, since we live in Sol's close-by neighborhood, have very direct effects here on Earth. As Attila has told me, the Sun "is not 'a hot ball of gas,' nor is it simply a fusion reactor (machine)." Rather, despite the fact that it is not a "carbon-based lifeform," the Sun gives evidence of behaving in ways that we associate only with living systems.
I'm tickled to see my friend, an astrophysicist who specializes on the Sun, cited here! Thank you so very much for the ping, marron!
Gee, I never in a million years thought that all this heating and cooling could possibly be caused by the sun. /sarc
Actually it is less now than 325,000 y/a and about the same as 125,000 years ago. It seem the CO2 levels and temperature go up and down on a pretty reliable schedule. About every 125,000 years both go up. We would seem to be at about the high point of that 125,000 peak and should be dropping off soon.
This graph brings up a question. Do the temps go up because of CO2 or do CO2 levels go up as temps rise?
Wrong Kemosabi. You are right that higher temps might mean more plant growth. However, plants sequester CO2. They take it out of the air and through photosynthesis combine the carbon with hydrogen and oxygen to produce starch which is stored in the plant as an energy source. As by-products they release O2 and water into the atmosphere as by-products. This would actually lower CO2 in the atmosphere and increase the level O2.
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The Sun: A Great Ball of Iron?
Science Daily
Posted on 07/18/2002 2:33:32 AM EDT by per loin
http://www.freerepublic.com/focus/f-news/718067/posts
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