Australian Politics Forum - What's Wrong with the Sun? (Nothing)

muso

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What's Wrong with the Sun? (Nothing)
Jan 13^th, 2009 at 9:29am

http://science.nasa.gov/headlines/y2008/11jul_solarcycleupdate.htm

"It does seem like it's taking a long time," allows Hathaway, "but I think we're just forgetting how long a solar minimum can last." In the early 20th century there were periods of quiet lasting almost twice as long as the current spell. (See the end notes for an example.) Most researchers weren't even born then."

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freediver Gold Member Offline www.ozpolitic.com Posts: 53282 At my desk.	Re: What's Wrong with the Sun? (Nothing) Reply #1 - Jan 13^th, 2009 at 9:56am Do they have a plot showing more than one cycle? The text creates the impression that it is highly variable, but the graphic creates the impression it is very predictable. What impact do the spots have?
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tallowood Gold Member Offline Израиль Навсегда Posts: 8648 Gender:	Re: What's Wrong with the Sun? (Nothing) Reply #2 - Jan 13^th, 2009 at 10:17am Wow, so next predicted Solar Max falls on 2012 coinciding with The End of Time according to Mayan calendar. Should we iInvest in to swimming pool and more air conditioners?
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Sprintcyclist Gold Member Offline OzPolitic Posts: 41922 Gender:	Re: What's Wrong with the Sun? (Nothing) Reply #3 - Jan 13^th, 2009 at 10:27am well spotted tallow.
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muso

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Re: What's Wrong with the Sun? (Nothing)
Reply #4 - Jan 13^th, 2009 at 1:25pm

freediver wrote on Jan 13^th, 2009 at 9:56am:

Do they have a plot showing more than one cycle? The text creates the impression that it is highly variable, but the graphic creates the impression it is very predictable.

What impact do the spots have?

The more sunspots, the more we get solar wind. We also get slightly increased irradiance during sunspot maxima. The variation is of the order of 0.1% of the solar constant (a peak-to-trough range of 1.3 W m-2) compared to 1366 W m-2 for the average solar irradiance.

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freediver Gold Member Offline www.ozpolitic.com Posts: 53282 At my desk.	Re: What's Wrong with the Sun? (Nothing) Reply #5 - Jan 13^th, 2009 at 2:11pm So what impact does that have on temperature, or whether? How consistent is the period? It's a bit hard to tell from that plot.
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tallowood

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Re: What's Wrong with the Sun? (Nothing)
Reply #6 - Jan 13^th, 2009 at 2:52pm

freediver wrote on Jan 13^th, 2009 at 2:11pm:

So what impact does that have on temperature, or whether?

How consistent is the period? It's a bit hard to tell from that plot.

It is in the article, sort of:
"The longest minimum on record, the Maunder Minimum of 1645-1715, lasted an incredible 70 years. Sunspots were rarely observed and the solar cycle seemed to have broken down completely. The period of quiet coincided with the Little Ice Age, a series of extraordinarily bitter winters in Earth's northern hemisphere. Many researchers are convinced that low solar activity, acting in concert with increased volcanism and possible changes in ocean current patterns, played a role in that 17th century cooling."

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muso

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Re: What's Wrong with the Sun? (Nothing)
Reply #7 - Jan 13^th, 2009 at 2:56pm

freediver wrote on Jan 13^th, 2009 at 2:11pm:

So what impact does that have on temperature, or whether?

How consistent is the period? It's a bit hard to tell from that plot.

The cycle repeats approximately every 11 years. It's reasonably consistent in terms of period, but not in terms of intensity.

You can predict that there will be more solar storms during a given maximum, but not how intense any given storm will be.

The other effect is on radio wave propagation. During periods of high flux, it can totally change the way the waves propagate.

It has very little direct effect on global temperature. As I said before, the variation in output is only of the order of 0.1%- 0.2%. (See the graph below)

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tallowood

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Re: What's Wrong with the Sun? (Nothing)
Reply #8 - Jan 13^th, 2009 at 3:30pm

Quote:

A number of techniques are used to predict the amplitude of a cycle during the time near and before sunspot minimum. Relationships have been found between the size of the next cycle maximum and the length of the previous cycle, the level of activity at sunspot minimum, and the size of the previous cycle.

Quote:

Radio bursts from solar flares can directly interfere with cell phone reception while coronal mass ejections (CMEs) hitting Earth can cause electrical power outages. "The most famous example is the Quebec outage of 1989, which left some Canadians without power for as much as six days."

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muso

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Re: What's Wrong with the Sun? (Nothing)
Reply #9 - Jan 13^th, 2009 at 3:38pm

tallowood wrote on Jan 13^th, 2009 at 3:30pm:

Quote:

A number of techniques are used to predict the amplitude of a cycle during the time near and before sunspot minimum. Relationships have been found between the size of the next cycle maximum and the length of the previous cycle, the level of activity at sunspot minimum, and the size of the previous cycle.

Yeah, but they are not very good at it yet. Current estimates for cycle 24 vary by as much as 50%.

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Re: What's Wrong with the Sun? (Nothing)
Reply #10 - Jan 13^th, 2009 at 4:16pm

muso wrote on Jan 13^th, 2009 at 3:38pm:

tallowood wrote on Jan 13^th, 2009 at 3:30pm:

Quote:

A number of techniques are used to predict the amplitude of a cycle during the time near and before sunspot minimum. Relationships have been found between the size of the next cycle maximum and the length of the previous cycle, the level of activity at sunspot minimum, and the size of the previous cycle.

Yeah, but they are not very good at it yet. Current estimates for cycle 24 vary by as much as 50%.

They claim that combination of different methods gives prediction of maximum sunspot number of 154 ± 21, which is about 14%
http://solarscience.msfc.nasa.gov/papers/hathadh/HathawayWilsonReichmann1999.pdf

Here are the predicted numbers
http://solarscience.msfc.nasa.gov/images/ssn_predict.txt

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muso Gold Member Offline Posts: 13151 Gladstone, Queensland Gender:	Re: What's Wrong with the Sun? (Nothing) Reply #11 - Jan 14^th, 2009 at 8:13am Yeah - That's one set of researchers The method is empirical anyway. They don't really know enough about the solar magnetic field reversals to be able to predict anything from first principles.
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