News About the Quiet Sun

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MeteorWayne

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I went back 6 months looking for a thread to revive and didn't find any so started a new one. NEw data has revealed what's different about this solar minimum...other than how long it has been.

http://www.space.com/scienceastronomy/0 ... cycle.html

Just looking at the number of sunspots doesn't provide a full picture of how the sun's solar energy impacts Earth, a new study suggests. The findings contradict previous thinking about how the sun behaves during low points in its solar cycle.

"What we're realizing is that the sunspots do not tell the whole story," said Sarah Gibson, a scientist from the National Center for Atmospheric Research (NCAR) in Boulder, Colo.
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During cycle peaks — the next one is expected in 2013 — there are frequent solar flares and geomagnetic storms, events that send out radiation that can bombard the Earth's atmosphere, damaging satellites and disrupting power grids. Scientists say that a really bad solar storm, akin to one that started fires along telegraph lines in 1859, could bring modern society to its knees.

Conversely, cycle minimums were thought to be very quiet times, periods when the Earth would not experience as many blasts of solar energy. But Gibson's study shows that this is not necessarily the case.

Full force in 2008

Gibson and her colleagues compared measurements from two different cycle minimums — one from 1996 and one from 2008. They analyzed a type of solar energy called the solar wind — streams of charged particles that accelerate out from the sun's extremely hot atmosphere. The solar wind, unlike short-lived solar storms, streams from the sun pretty much constantly but with varying intensity.

They found that, while the solar winds intersecting the Earth largely disappeared in 1996, they continued to hit the Earth at full force in 2008.

These results show that "what we thought was a typical solar minimum wasn't, and what we're seeing now is a different animal," Gibson said.

Scientists previously thought that during solar minimums, solar winds would simply blow out the top and the bottom of the sun, and not come out near the equator. Since the Earth is close to the same latitude as the sun's equator, it shouldn't experience much solar wind during a low point in the solar cycle.

"If you imagine holding a hose and you hold it straight up, you would spray up, and if you had a friend standing nearby, they might get a little wet, but not soaked," Gibson said. But during the current solar minimum in 2008, the fire hose was still pointing at the Earth.

"The last two solar minimum, this didn't happen. When the sun spots went away, these fire hoses went away too," she said.

In fact, the solar wind's effect on the Earth's radiation belt — a ring of charged particles around the planet — was three times greater in 2008 than in 1996. While the effects of solar winds aren't as drastic as those of a solar flare, they can still interfere with satellite orbits and radio communications.

Changing as you read this

This year, the solar winds are starting to taper off. However, Gibson was surprised that the reduction of winds lagged so far behind the decrease in sunspots.

What could account for this difference in minimums? Gibson thinks it may have something to do with the fact that this cycle's minimum has been historically wimpy — there were fewer sunspots during this minimum than during any minimum in the last 75 years.

"In a minimum when you have a really strong polar field, it can clamp down everything else at lower latitudes down towards the equator, and really the only action is what's coming out the poles, and you get what we thought was a classic solar minimum picture, and you don't get any wind escaping," Gibson said. "But because we have such a weak magnetic field this cycle compared to last cycle minimum ... the polar field is not as strong, it can't clamp down, and stuff kind of escapes, you get these streams that squirt out at lower latitudes near the equator instead of just at the poles," she said.

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michaelmozina

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http://en.wikipedia.org/wiki/Solar_cycle

I'm a little curious why they selected a 12 year separation between solar minimums (96 and 08) rather than 11 years, and whether it would have made a difference in their findings to use an 11 year separation rather than 12?
 
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MeteorWayne

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D'oh, that's based on the current data, michael...in case you haven't noticed this minimum has lasted longer than usual....
 
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michaelmozina

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MeteorWayne":1ue1hmgx said:
D'oh, that's based on the current data, michael...in case you haven't noticed this minimum has lasted longer than usual....

I realize that this particular quiet phase has lasted longer than normal, but I still can't help but wonder what a 1996 to 2007 comparison would look like? 2007 is the actual "half way" point of the sun's 22 year rotation cycle rather than 2008. In an ideal world it would be nice to have data from several complete solar cycles so that we know what the solar wind "normally" does at each phase of the cycle. Maybe every other 11 year cycle experiences more (or less) solar wind than the next 11 year point due to the sun's magnetic field alignments? It's hard to tell from such a limited data window. It's very interesting however that there are differences in wind speed between different "quiet" (sunspot) phases.

I would tend to say that sunspots tend to require a significant amount of concentrated 171A (or 195A/284A) activity in order for sunspots to form and we just haven't seem much activity in the higher energy wavelengths recently. Fortunately there is at least one active region on the backside of the sun that should make it's way toward us in another week. How (or if) that concentration of activity relates to the overall solar wind speed is really an interesting question. Evidently solar wind speed isn't necessarily directly related to sunspot activity.
 
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MeteorWayne

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You seem to be under the mistaken impression that there is a precise 22/11 year cycle length; that is not the case at all. That is a rough average length. If you examine the record over the last few centuries you will find there is considerable variation around than mean length.
 
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michaelmozina

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MeteorWayne":2zqptrz9 said:
You seem to be under the mistaken impression that there is a precise 22/11 year cycle length; that is not the case at all. That is a rough average length. If you examine the record over the last few centuries you will find there is considerable variation around than mean length.

Actually, I'm aware that the cycle somewhat variable, but I can't help but wonder what we would discover by being able to look at the patterns of say 100 years worth of solar wind data. What might we discover? I'm really interested in seeing some of the recent IBEX data since it also must tell us quite a bit about recent solar wind activity inside the solar system and near and around the heliosphere. It should be quite revealing.

I am of the impression that activity in higher wavelengths must be relatively "concentrated" around the surface for sunspots to form in the photosphere. The solar wind is more of "whole sphere" type of activity with faster wind emissions located nearer the polar regions rather than the equator. It seems to me that sunspots require 'more than" simple solar wind processes, and require a visible "concentration" of energy releases that are visible in higher energy wavelengths. The solar wind does tend to pick up in the more active phases, but there may be some delay between the wind speed acceleration and the 'concentration' of energy required to generate prolonged sunspots in the photosphere.

I hear you on the cycle variability issue. I guess I'm simply pondering what we might learn from a large set of solar wind data that spans a number of cycles. No matter what one knows about astronomy, there's always another angle, and always another set of interesting data to consider. :)
 
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SpaceTas

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Very long time series of solar wind strength have been done already via C13/C12 ratio. The solar wind + its magnetic field modulates cosmic ray flux on Earth. Stronger wind/field less cosmic rays get through, less C13 produced.
Can't remember exactly quasi periods, near 90 year, 200 year, 1000 year.
 
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Broomstacker

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Sun Activity Picking Up

As the Sun exits the current quiet period, the hi-res images (SOHO/Stereo) will show us detail never before seen. Folks are already starting to buzz about "objects in the corona" and "orbiting the sun"! See YouTube video below.

What's the simplest explanation to give them so they don't start screaming about "the invasion fleet from Tau ceti"?

http://www.youtube.com/watch?v=fqXUmnVx ... r_embedded
 
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MeteorWayne

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Re: Sun Activity Picking Up

I'm probably going to move this to a thread in Space Science and Astronomy where this discussion is already in process. I'll leave it here for a while until I've had time to look at the youtube video.
 
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origin

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Re: Sun Activity Picking Up

Broomstacker":19u0eqg0 said:
As the Sun exits the current quiet period, the hi-res images (SOHO/Stereo) will show us detail never before seen. Folks are already starting to buzz about "objects in the corona" and "orbiting the sun"! See YouTube video below.

What's the simplest explanation to give them so they don't start screaming about "the invasion fleet from Tau ceti"?

http://www.youtube.com/watch?v=fqXUmnVx ... r_embedded

Oh boy, give me a "U"

The simplist explanation is that the movie maker is enlarging, changing the contrast, and brightening small imperfections in the photographs, making nothing look like something.

The most far fetched explinations is that there are earth sized alien space ships in the corona of the sun.
 
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MeteorWayne

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Re: Sun Activity Picking Up

Yeah, I will move to The Unexplained, but leave a copy here for a day or two.

As for what they are, just normal holes and small knots of material contentraed in the magnetic field of the sun. Same stuff that's always there. There might even be some energetic particle hits on the detectors from the sun, but I only lasted a minute on the video since it was such garbage. Maybe I'll try again later.
 
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Askholt

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Alarmingly low sun activity

I have been following the suns activity for a while and I am a little concerned about the number of sunspots.
For over a year there has been an extraordinary low count of sunspots. It is normal for the sun to be less active now but not this quiet for this long! Last time the sun was this inactive was in 1823(inactive 1 year) and 1810(2 years). This period is also called “Dalton Minimum”.
Before Dalton Minimum there was a long period (about 1650-1725) with almost no sunspots observed. This period is called “Maunder Minimum” and the lack of sun activity caused a little ice age!
Are we heading for another long cold period or is it simply a matter of months before the sun starts turning the heat on?
It is possible to track the suns activity at: http://solarcycle24.com/
 
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MeteorWayne

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Re: Alarmingly low sun activity

This will be merged with one of the other 2 or 3 active threads discussing this subject
 
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Askholt

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Re: Alarmingly low sun activity

Could you please give me a link to the thread you have merged my post with?
 
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MeteorWayne

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Re: Alarmingly low sun activity

I will when I decide what to do with all the others. I'll probably merge them all into one.
 
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trumptor

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Re: Alarmingly low sun activity

I was under the impression that the sun spots were coming back. No?
 
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MeteorWayne

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Re: Alarmingly low sun activity

Yes, Cycle 24 has begun. That's the subject of one of the threads. I found the oldest discussion, it's in Space Science and Astronomy which is where all these will wind up in an hour or so.
 
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