Missing sunspots: Solar mystery solved

Mar 02, 2011
This visible-light photograph, taken in 2008 by NASA's Solar and Heliospheric Observatory (SOHO) spacecraft, shows the sun's face free of sunspots. The sun experienced 780 spotless days during the unusually long solar minimum that just ended. New computer simulations imply that the sun's long quiet spell resulted from changing flows of hot plasma within it. Credit: NASA/SOHO

The Sun has been in the news a lot lately because it's beginning to send out more flares and solar storms. Its recent turmoil is particularly newsworthy because the Sun was very quiet for an unusually long time. Astronomers had a tough time explaining the extended solar minimum. New computer simulations imply that the Sun's long quiet spell resulted from changing flows of hot plasma within it.

"The Sun contains huge rivers of plasma similar to Earth's ," says Andres Munoz-Jaramillo, a visiting research fellow at the Harvard-Smithsonian Center for Astrophysics (CfA). "Those plasma rivers affect in ways we're just beginning to understand."

The Sun is made of a fourth state of matter - plasma, in which negative electrons and positive ions flow freely. Flowing plasma creates magnetic fields, which lie at the core of solar activity like flares, eruptions, and sunspots.

Astronomers have known for decades that the Sun's activity rises and falls in a cycle that lasts 11 years on average. At its most active, called solar maximum, dark sunspots dot the Sun's surface and frequent eruptions send billions of tons of hot plasma into space. If the plasma hits Earth, it can disrupt communications and electrical grids and short out satellites.

During solar minimum, the Sun calms down and both sunspots and eruptions are rare. The effects on Earth, while less dramatic, are still significant. For example, Earth's shrinks closer to the surface, meaning there is less drag on orbiting space junk. Also, the that blows through the solar system (and its associated magnetic field) weakens, allowing more to reach us from interstellar space.

The most recent solar minimum had an unusually long number of spotless days: 780 days during 2008-2010. In a typical solar minimum, the Sun goes spot-free for about 300 days, making the last minimum the longest since 1913.

"The last solar minimum had two key characteristics: a long period of no sunspots and a weak polar magnetic field," explains Munoz-Jaramillo. (A polar magnetic field is the magnetic field at the Sun's north and south poles.) "We have to explain both factors if we want to understand the solar minimum."

To study the problem, Munoz-Jaramillo used to model the Sun's behavior over 210 activity cycles spanning some 2,000 years. He specifically looked at the role of the plasma rivers that circulate from the Sun's equator to higher latitudes. These currents flow much like Earth's ocean currents: rising at the equator, streaming toward the poles, then sinking and flowing back to the equator. At a typical speed of 40 miles per hour, it takes about 11 years to make one loop.

This video is not supported by your browser at this time.
A simulation of solar magnetic fields.

Munoz-Jaramillo and his colleagues discovered that the Sun's plasma rivers speed up and slow down like a malfunctioning conveyor belt. They find that a faster flow during the first half of the solar cycle, followed by a slower flow in the second half of the cycle, can lead to an extended solar minimum. The cause of the speed-up and slowdown likely involves a complicated feedback between the plasma flow and solar magnetic fields.

"It's like a production line - a slowdown puts 'distance' between the end of the last solar cycle and the start of the new one," says Munoz-Jaramillo.

The ultimate goal of studies like this is to predict upcoming solar maxima and minima - both their strength and timing. The team focused on simulating solar minima, and say that they can't forecast the next solar minimum (which is expected to occur in 2019) just yet.

"We can't predict how the flow of these plasma rivers will change," explains lead author Dibyendu Nandy (Indian Institute of Science Education and Research, Kolkata). "Instead, once we see how the flow is changing, we can predict the consequences."

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User comments : 20

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omatumr
1.9 / 5 (13) Mar 02, 2011
Solar flares arise from the dense, compact object hidden from view by brightly glowing waste products in the photosphere.

See: B. W. Ninham (1963) "Charged Bose gas in astrophysics", Physics Letters 4, 278-279.

and "Super-fluidity in the solar interior: Implications for solar eruptions and climate" [Journal of Fusion Energy, vol. 21 (Dec 2002) pp. 193-198]

arxiv.org/pdf/astro-ph/0501441v1

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo
omatumr
1.7 / 5 (12) Mar 02, 2011
See also: "Neutron Repulsion"
The APEIRON Journal
in press (2011), 19 pages

arxiv.org/pdf/1102.1499v1
brant
1.8 / 5 (5) Mar 02, 2011
Rivers of plasma implies electric currents. The only way you can have rivers of plasma is through a right hand rule z-pinch effect which causes the plasma to form into rivers. We call them filaments.
Nik_2213
5 / 5 (6) Mar 02, 2011
Nice to see that a solar oddity has progressed our understanding of the Sun's deep currents...

OT:{Sigh} Surely a compact core would be evident from the helioseismology findings ??
astro_optics
2.8 / 5 (11) Mar 02, 2011
I agree with the Alarmists, this was man made solar minimum :P
Shelgeyr
2.5 / 5 (10) Mar 02, 2011
Oh man...
Missing sunspots: Solar mystery solved

Guys, please stop with the undeservingly definitive headlines...
Flowing plasma creates magnetic fields... (snip)

No. Electric currents create magnetic fields, they're the only things that ever can and do.

We could grant the article partial credit on this point if it bothered to explain that plasma flowing in a circuit = charged particles moving in a circuit = an electric current, so had they included such details or a qualifier then they'd be correct. But this is like saying "cars weaving randomly across the road create a traffic hazard" (well, yeah...) when the point is that drunk drivers create a traffic hazard.

The cause of the speed-up and slowdown likely involves a complicated feedback between the plasma flow and solar magnetic fields.

They don't actually know.
"We can't predict how the flow of these plasma rivers will change,"


The headline is misleading in the extreme. NOT "solved".
Doom1974
5 / 5 (3) Mar 02, 2011
I was betting with myself that OT had already the explanation...
MorituriMax
Mar 02, 2011
This comment has been removed by a moderator.
omatumr
1.9 / 5 (9) Mar 02, 2011
Surely a compact core would be evident from the helioseismology findings ??


It was reported in Nature: "Is the Sun a pulsar?" by Peter Toth, Nature 270, 159 - 160 (10 November 1977); doi:10.1038/270159a0

nature.com/nature/journal/v270/n5633/abs/270159a0.html

Caliban
4.3 / 5 (6) Mar 02, 2011
Oh man...


Flowing plasma creates magnetic fields... (snip)


No. Electric currents create magnetic fields, they're the only things that ever can and do.


I'm veering the tiniest bit off-topic here, but don't forget permanent magnets.

Maxbyte
5 / 5 (1) Mar 02, 2011
Interesting stuff. Doesn't really seem the matter is "solved", however. I came across parts of this post earlier, so was surprised to see "mystery solved" in the headline. Or perhaps I'm missing more definitive work than that presented here? From simulation to accurate prediction? Let's hope.
Shelgeyr
4 / 5 (8) Mar 02, 2011
Caliban, thanks, you have not veered the slightest bit off course with your comment, and I appreciate you bringing it up because there's a whole lot of misunderstanding on the subject.

It took me a long time to wrap my brain around it too, but apparently even the magnetic fields around permanent magnets are created by electric currents. And I mean like ongoing active atomic-level electric currents. Though I wouldn't normally consider Wikipedia reliably authoritative, I think it's OK to recommend you look up their article on "Magnet", and scroll down to the bit on "Ampère model". I'd post a link but physorg tends to freeze on me when I do. Here's a small excerpt:
Another model is the Ampère model, where all magnetization is due to the effect of microscopic, or atomic, circular bound currents, also called Ampèrian currents, throughout the material.
GuruShabu
1.4 / 5 (10) Mar 02, 2011
I agree with the Alarmists, this was man made solar minimum :P

Astro, you have revealed the IPCC agenda too earlier!
C'mon, everyone knows we have caused (we the dirty Earthling producers of CO2!) the Solar Minimum....but please, do not use Solar Minimum, use Solar Changing....:)
We have to be consistent!
Caliban
3.7 / 5 (3) Mar 02, 2011
Caliban, thanks, you have not veered the slightest bit off course with your comment, and I appreciate you bringing it up because there's a whole lot of misunderstanding on the subject.

It took me a long time to wrap my brain around it too, but apparently even the magnetic fields around permanent magnets are created by electric currents. And I mean like ongoing active atomic-level electric currents. Though I wouldn't normally consider Wikipedia reliably authoritative, I think it's OK to recommend you look up their article on "Magnet", and scroll down to the bit on "Ampčre model". I'd post a link but physorg tends to freeze on me when I do. Here's a small excerpt:


Thanks, I'll check it out.

If you want to post a link, just insert "DELETE" into the string, or a couple of spaces -anyway, something obvious, that can then be easily removed, and the link then cut/pasted into browser.
astro_optics
1 / 5 (8) Mar 02, 2011
GuruShabu you're the MASTER!
lengould100
Mar 03, 2011
This comment has been removed by a moderator.
Shelgeyr
2.4 / 5 (7) Mar 03, 2011
Buy a neuron or two, guys.

OK, got one. They were on sale.

Now what?
MarkyMark
Mar 03, 2011
This comment has been removed by a moderator.
Paljor
5 / 5 (1) Mar 03, 2011
how could we affect something like the sun? and how could co2 get over to the sun and affect it's currents
CarolinaScotsman
5 / 5 (2) Mar 03, 2011
Concerning the title: it sounds like an Agatha Christie novel--"Hercule Poirot and the Case of the Missing Sunspots".
Modernmystic
2.1 / 5 (7) Mar 03, 2011
A computer model "proves" this...

Mmmmkay.

Sounds like another theory that computer models have supposedly "settled"...
Kio
1.7 / 5 (6) Mar 03, 2011
In reality the spot activity interrelated to highly radioactive matter and violent nucleo-synthesis reactions within the spot-interiors, by means of the violent thermo-nuclear bombardment through the shell.

Disappearance of the sunspots is interrelated to minimal intensities of the summary magnetic field. At the equality stage, the changeable magnetic field of the core indicates almost equality intensity to the opposite and almost permanent value, which is formed by the turbulent convection streams in the shell.

At the equality stage the triply alpha processes and their streams from the core magnetic poles are ceased. Thus desapearence of the magnetic confinement is interrelated to the finish of the triply alpha processes. The core magnetic poles can produce only thermonuclear reactions. Thus Sun explodes the spot remains and eventually we can not observe temporarily the spot activity process.
Kakha.
beelize54
1 / 5 (6) Mar 03, 2011
The signs of global warming across whole solar system, the higher frequency of asteroids hits, the shifts of magnetic poles, increased geovolcanic activity etc. are indicating, the cause of the solar minimum isn't "a complicated feedback between the plasma flow and solar magnetic fields", but it has an origin outside of Sun. IMO solar system is passing through dense cloud of interstellar gas or dark matter, the antineutrinos in particular and it shifted the center of solar system beneath the surface of Sun, which stopped the switching of conveyor belts of plasma.

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