From the National Science Foundation:
Answer lies in jets of plasma
One of the most enduring mysteries in solar physics is why the Sun’s outer atmosphere, or corona, is millions of degrees hotter than its surface.
Now scientists believe they have discovered a major source of hot gas that replenishes the corona: jets of plasma shooting up from just above the Sun’s surface.
The finding addresses a fundamental question in astrophysics: how energy is moved from the Sun’s interior to create its hot outer atmosphere.
“It’s always been quite a puzzle to figure out why the Sun’s atmosphere is hotter than its surface,” says Scott McIntosh, a solar physicist at the High Altitude Observatory of the National Center for Atmospheric Research (NCAR) in Boulder, Colo., who was involved in the study.
“By identifying that these jets insert heated plasma into the Sun’s outer atmosphere, we can gain a much greater understanding of that region and possibly improve our knowledge of the Sun’s subtle influence on the Earth’s upper atmosphere.”
The research, results of which are published this week in the journal Science, was conducted by scientists from Lockheed Martin’s Solar and Astrophysics Laboratory (LMSAL), NCAR, and the University of Oslo. It was supported by NASA and the National Science Foundation (NSF), NCAR’s sponsor.
“These observations are a significant step in understanding observed temperatures in the solar corona,” says Rich Behnke of NSF’s Division of Atmospheric and Geospace Sciences, which funded the research.
“They provide new insight about the energy output of the Sun and other stars. The results are also a great example of the power of collaboration among university, private industry and government scientists and organizations.”
The research team focused on jets of plasma known as spicules, which are fountains of plasma propelled upward from near the surface of the Sun into the outer atmosphere.
For decades scientists believed spicules could send heat into the corona. However, following observational research in the 1980s, it was found that spicule plasma did not reach coronal temperatures, and so the theory largely fell out of vogue.
“Heating of spicules to millions of degrees has never been directly observed, so their role in coronal heating had been dismissed as unlikely,” says Bart De Pontieu, the lead researcher and a solar physicist at LMSAL.
In 2007, De Pontieu, McIntosh, and their colleagues identified a new class of spicules that moved much faster and were shorter-lived than the traditional spicules.
These “Type II” spicules shoot upward at high speeds, often in excess of 100 kilometers per second, before disappearing.
The rapid disappearance of these jets suggested that the plasma they carried might get very hot, but direct observational evidence of this process was missing.
The researchers used new observations from the Atmospheric Imaging Assembly on NASA’s recently launched Solar Dynamics Observatory and NASA’s Focal Plane Package for the Solar Optical Telescope (SOT) on the Japanese Hinode satellite to test their hypothesis.
“The high spatial and temporal resolution of the newer instruments was crucial in revealing this previously hidden coronal mass supply,” says McIntosh.
“Our observations reveal, for the first time, the one-to-one connection between plasma that is heated to millions of degrees and the spicules that insert this plasma into the corona.”
The findings provide an observational challenge to the existing theories of coronal heating.
During the past few decades, scientists proposed a wide variety of theoretical models, but the lack of detailed observation significantly hampered progress.
“One of our biggest challenges is to understand what drives and heats the material in the spicules,” says De Pontieu.
A key step, according to De Pontieu, will be to better understand the interface region between the Sun’s visible surface, or photosphere, and its corona.
Another NASA mission, the Interface Region Imaging Spectrograph (IRIS), is scheduled for launch in 2012 to provide high-fidelity data on the complex processes and enormous contrasts of density, temperature and magnetic field between the photosphere and corona. Researchers hope this will reveal more about the spicule heating and launch mechanism.
The LMSAL is part of the Lockheed Martin Space Systems Company, which designs and develops, tests, manufactures and operates a full spectrum of advanced-technology systems for national security and military, civil government and commercial customers.
-NSF-
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Heating up the upper atmosphere. Isn’t that caused by the greenhouse effect? Maybe the greenies should look for traces of CO2 in the Sun’s atmosphere.
Millions of degrees? That’s as hot as the earth’s mantle, according to Al Gore.
Can we send some AGW
grant-consumersscientists there to collect some core samples? That would surely advance our understanding of the factors on earth.tallbloke says:
January 7, 2011 at 8:28 am
That is an issue which belongs to the “Holy Index”of forbidden things. Your are risking to be excomulgated or, worse, being prosecuted by the Holy Inquisition of the Post Normal and Progressive Church. 🙂
Dave Springer says:
January 7, 2011 at 7:30 am
“You couldn’t measure its temperature with any kind of actual thermometer – the temperature must be inferred by spectral analysis of the radiation coming from it.”
Which is a another good example of why temperature is not a good measure of the heat content of something.
Tom in Florida says:
January 7, 2011 at 7:28 am
Those differences are due to what is happening on Earth not on the Sun.
I realize that. My point was that they are claiming the sun only has subtle affect on the upper atmosphere. When the Earth wobbles and rotates, it makes the particular location where you are either a little closer or a little farther away from the sun (a relatively small change) or it puts you in direct sunlight or complete darkness. Those changes affect the temperature dramatically throughout all layers of the atmosphere. They seem to be missing the point that a little change in the overall equation can make a huge difference overall. Many “scientists” today make claims about many atmospheric and galactic processes only to find out they were wrong once actual evidence is gathered. They always seem to miss the obvious common sense knowledge that most of us unintelligent rabble (who are obviously just shills for the big oil industry) can see quite easily.
ferd berple says:
January 7, 2011 at 8:27 am
No, it is not likely that science has the best minds, certainly not in the US. Science related job in the US tend to pay only a fraction of what can be earned in finance, investment, law and medicine. As a result, science has become an easy target for political corruption.
Interesting assumption here that the only possible motive that drives the “best minds” is money. Perhaps this says more about you than about scientists?
it’s interesting to note the reactions.
possibly improve our knowledge of the Sun’s subtle influence on the Earth’s upper atmosphere
Wow… what else has any effect has any influence what-so-ever on Earth’s upper atmosphere? Ok, lunar tides, a little tug from Jupiter, Earth’s lower atmosphere gets a jab in here & there, but Sol is the 800 pound gorilla.
It is obvious. COrOna is 50% CO2.
LIEF !!!
Sorry LEIF
Murray said, “Can we send some AGW grant-consumers scientists there to collect some core samples? That would surely advance our understanding of the factors on earth.”
What a dubious idea, you speak as a skeptics or denier or something, give you samples and data…
Collecting samples, especially correctly, is a tedious task. Millions degrees is a lot, could burn something. I have a better idea. How about we unite and organize a mass movement to protect solar corona from those vicious hot spicules? And get some grants for mitigation studies that do not need any samples? Donations are also accepted, in my personal account…
Cheers,
– Al Tekhasski
The Earth’s Corona it is called Thermosphere.
“Why do the headlines always have an order of magnitude more certainty than the body of the work?”
Anthony, I’m all for discussing this idea. I appreciate the opportunity, because I am very curious what the answer to this question is.
But that headline was nothing less than blatantly misleading.
Millions of degrees- can be misleading to the layperson in the same way as saying that the vacuum of space is -273 celcius. In truth, a vacuum has no temperature- you could say neutral. I always used to think that a person exposed to space would instantly freeze solid- not true. The first worry with exposure are the body tissues exploding due to the pressure gradiant. Astronauts have to worry more about overheating during spacewalk than the freezing, as without atmosphere, body heat has no where to escape.
Sorry, I am going with Hydrinos:
http://www.blacklightpower.com/pdf/SOLAR.pdf
The physics here is interesting and should be considered. Maybe it is the explanation. But the author’s of the work carry nothing like that certainty, and Anthony seeks to put the debate to rest with a strongly worded headline.
Even if you think this is the probable explanation, I think you’ll have to agree that this headline was a serious overreach.
I believe what they’re saying is that the jets are very hot, and there are many of them.
ferd berple says:
January 7, 2011 at 8:27 am
If the spicules heat the corona, what heats the spicules?
Good question. The problem has not been solved, just moved elsewhere. Now, everything explosive that happens is caused by strong electric currents. There are several ways to get electric currents. One basic mechanism is ‘induction’: rapid changes in the magnetic field induces electric currents. There are several ways to get changes in the magnetic fields [e.g. reconnection, or just movements of plasma pushing the field around], so there are many details to work out. One thing that is often [almost always, in fact] overlooked is that the corona is very tenuous. The [less conspicuous – nice pun here] chromosphere where the spicules live has hundreds of times more mass and energy than the corona.
Josh Grella says:
January 7, 2011 at 9:33 am
Those changes affect the temperature dramatically throughout all layers of the atmosphere. They seem to be missing the point that a little change in the overall equation can make a huge difference overall.
Those changes are not ‘little’. Day-night is 100% effect. Varying distance is 7%, which is 70 times larger than the solar cycle variation of solar energy output. [and the distance effect is even hard to see: right now we are closest to the Sun]
Re: “What say the Electric Sun people?”
If you guys don’t find this “explanation” to be satisfactory, then you really need to read Zirker’s Journey from the Center of the Sun. And you will come to see that this entire solar model is in no way better than Wal Thornhill’s plasma glow discharge model for the Sun.
The entire model is constructed in an ad hoc manner: Looks like we have these big bubbles of gas. Let’s call them supergranules and propose that they represent convection. But, it looks like we have enigmatic temperatures in the corona. Okay … hmm … Let’s suppose that magnetic fields can do things which we’ve yet to observe in the laboratory … Etc.
It’s just barely “science”, and it certainly has very little to do with the laboratory.
Yes, the SSM does indeed provide a way in which the thermonuclear core idea can *possibly* be made to work. But, that’s perhaps the best way to put it right there.
And, what are your expectations? If you expect that the behavior of the Sun should *naturally* follow from some sort of underlying physics which has been validated within the laboratory, then you unknowingly are in the electric sun camp. We can explain all of these features with laboratory plasma physics. Conventional solar physicists just opt not to, because they are in love with the idea of the thermonuclear core. After all, it’s what they were taught in college.
I see a few of you guys complaining that this article isn’t very convincing. But, so long as you refuse to seriously consider alternative ideas, you are bound to making the SSM work. I suggest learning to love it.
Studying the behavior of a laboratory glow discharge, and inferring the behavior of the Sun from those observations is hardly speculative. People just choose to not follow this line of investigation BECAUSE THEY DON’T LIKE THE IDEA OF AN EXTERNALLY POWERED SUN.
This is conclusion-driven science, and it’s not very different from claiming that the universe *must* dominated by gravity even as galactic rotation curves are easily reproduced by tweaking the cosmic plasma models such that they more closely represent our laboratory observations.
I don’t know about you guys, but I’m becoming more cynical by the day that the answers will be found here on wattsupwiththat. There’s quite a bit of assertions that it-just-can’t-be and far too few questions … and far too few people willing to read things which they don’t already believe. Starting to think that this forum is just like most others.
Anybody know where the critical thinkers are out there? I’d like to build a solar model.
PaulM says:
January 7, 2011 at 7:27 am
This doesn’t explain the problem at all.
The sun’s surface is about 6000 degrees.
The corona is over a million degrees.
So how does a jet of material from the surface help?
I think of the the corona as being the hot end of a gas flame (analogy) . I used to use a oxy/propane gas cutter when i worked in industry and i always wondered why the part of the flame two thirds of the way from the gas nozzle was the hottest and why the nozzle was never melted away. But thinking about it the gas was under pressure and the igniting part of the gas was well away from the nozzle on ignition. Maybe something is igniting away from the sun (at least expanding and exploding). But i’m not a physicist just a humble caulker burner (was).
Martin in England
Like others, I’m not understanding how these plasma jets are able to heat the corona to millions of degrees. Something must be missing in this article if it pretends to “explain” anything. What temperature is the plasma? What heats the plasma? And what keeps it hot as it disperses through the corona?
“Pssssssst”
As PaulM points out the photosphere of the sun is 6000 degrees. So, we have these high speed spicules going from the surface to the photosphere carrying mass at, uh, 6000 degrees?? Oh wait, they said the spicules were hot enough to add to the heated mass of the corona.
But, where is the explanation for how those spicules get heated to millions of degrees again??? ““One of our biggest challenges is to understand what drives and heats the material in the spicules,” says De Pontieu.”
So, they really don’t have an answer of any kind, just observations that hot material is being injected into the corona. Barring Star Trek transporters, I think we could have guessed that one.