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The Secret of the Sun's Heated Atmosphere
eldavojohn writes "There has long been speculation on why the Sun's surface is a mere ten thousand degrees while the atmosphere can reach millions. Space.com is reporting that the mystery has now been solved. Researchers looked for Alfven waves in the solar chromosphere and found them. Followup studies employing simulations demonstrated that the energetics work out to transfer energy from the Sun's surface to its overlying corona.. The magnetic waves may also be the power source behind the solar wind."
Hannes Alfven strongly advocated against magnetic reconnection and any theory of the corona's temperature that outright assumes that electricity is not involved. The idea that astrophysicists would attach his name to a theory that he vigorously fought against is a clear indication of peoples' lack of knowledge with regards to the history of science associated with his work. This has to be the ultimate form of scientific disrespect for what was in fact a very great man! Alfven started out as a power grid engineer! He studied electrical currents, people. Shame on Space.com for carrying this article and shame on the astrophysical community who persist in using his name to trumpet a cause for which he so vigorously fought against. And shame on everybody for just going along with the idea that Maxwell's Equations are meaningless in space. When you see a magnetic field, your first question should always be, "Where's the current?" To assume that it is not present even when you can see the magnetic field is just mind-boggling!
Are astrophysicists just unaware, or are they being malicious?
"A man cannot begin to learn that which he thinks he already knows." --Epictetus, 1st Century A.D.
Good joke, but...actually,
- the correct spelling uses a diacritical mark over the 'e', as wikipedia indicates: "Alfén."
- the correct pronunciation is more like ahlf'-vay-uhn or ahlf'-vay-n or ahlf'-vayn (with the last vowel sound a "schwa" nearly collapsed into the 'é' if it's even pronounced at all).
I am not Swedish, but this is how I've heard native Swedish speakers pronounce it when asked specifically about how to pronounce his name.
captcha: neutrino, no joke!
What powers the Sun?
... but as he published it, in Russian, in a physics journal that had essentially no circulation outside the (then) USSR, in the 1950s, he missed getting the glory for it).
Here is a good overview, written in 1996, of the standard solar model (SSM) (http://www.ap.stmarys.ca/~guenther/Level01/solar/what_is_ssm.html).
In a nutshell, the SSM matches a wide range of relevant observables, from the Sun's mass, its 'sound spectrum' (helioseismology - the solar equivalent of seismology), its radius, its energy output, the constancy of that energy output (time periods of years to billions of years), its (estimated, inferred) composition, and so on*.
In 1996, there was one, very annoying, exception - the flux of neutrinos from the Sun seemed to be way too low!
This very nice article by John Bahcall^, on the Nobel website, tells the story of how 'the solar neutrino problem' was solved (http://nobelprize.org/nobel_prizes/physics/articles/bahcall/index.html; it turns out that the original author of the the 'MSW' neutrino oscillation theory was actually Bruno Pontecorvo
There is, as SD readers know from pln2bz's comments, an alternative view of what powers the Sun: giant electric currents throughout the galaxy. As far as I know, this 'Electric Universe' idea (EU) has no basis, either in terms of quantitatively matching any significant subset of the relevant observations, or in terms of the underlying theory (ask an EU proponent about how much experimental support there is for the EU idea of what supports the Sun against gravitational collapse, to take just one example; or to characterise the current which powers the Sun, in terms of charge carriers, flux, speeds, and so on, and how well this characterisation matches what inter-planetary probes such as Ulysses or Galileo or Cassini have detected).
* If any reader is interested in reading more on this, right up to the latest ApJ papers, just holler!
^ Bahcall was one of the greats of 20th century astronomy; although he didn't share the Nobel for discovering the solution, his decades-long work on the problem (including his encouragement of Davis, who did get the Nobel) was crucial to that solution.
"the solar wind continues to accelerate even as it passes the planets!"
No, it doesn't. I looked it up once before in an argument with an electric universe guy and I'm too lazy to do it again, but you can find the velocity of the solar wind as measured by SOHO and also by Voyager with a quick Google. I found an average value for Earth's neighborhood as well. Guess what? Fastest at SOHO, slower at Earth, slowest as measured by the Voyagers. That is, the solar wind slows down as it "passes the planets." The solar wind DOES accelerate within a few radii of the sun's surface but it certainly does not accelerate farther out.
The charged solar wind / accelerating solar wind idea isn't even the least bit logically consistent even if it didn't disagree with EVERY observation, both of the actual speed of the solar wind and its composition.
Another strike for the electric universe.