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Space Science

The Sunspot Cycle Explained 133

Posted by michael from the blister-on-the-sun dept.
An anonymous reader writes "After the recent spate of auroras visible as far south as Florida and Greece, and radio amateurs having lots of fun bouncing their signals off the auroral curtain, maybe some explanation was needed. It has been known for a while that the peak of solar activity trail trails the sunspot cycle peak by a couple of years, but this BBC article appears to explain why. As you may expect most of the data came from the SOHO satellite and the theory has been put together by some scientists using what appears to be data mining."
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The Sunspot Cycle Explained More

The Sunspot Cycle Explained

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  • Re-run (Score:2, Funny)

    by allanweber ( 467416 )
    radio amateurs having lots of fun bouncing their signals off the auroral curtain

    Could this mean, that when I'm watching a re-run of my favorit tv-shop, it is actually a re-re-run??

  • Links to the abstracts (Score:5, Informative)

    by mattjb0010 ( 724744 ) on Saturday November 22, 2003 @06:29AM (#7535582) Homepage
    As easy as one [uchicago.edu], two [uchicago.edu], three [uchicago.edu].

  • Argh! (Score:1, Funny)

    by Anonymous Coward
    First e-bombing, now data-mining. They're really putting the Slash back into Slashdot!
  • Now if only someone could explain the relationship [carolmoore.net] between the sunspot cycle and wars and revolutions in the history of mankind, that would be cool...
    • Easy, just write down all the wars and revolutions that don't coincide with the sunspots. :)
      • I don't think it's that simple. If you read history, you notice striking years of world-wide turmoil like 1848, 1863, 1905, 1968 or 1989. Take the 1968, the most obvious one. Why did the students of Beijing, Berlin, Warsaw, Prague, Paris, Mexico City and Berkeley take it to the streets the same year? They didn't even fight for similar cases! Don't tell me that every year was like 1968, because it just wasn't.
        • Or the Boer war which many parts of the British empire were involved with during a low part of a cycle. Anything can look significant if you pick and choose.

        • Re:Wars and revolutions (Score:3, Insightful)

          by bj8rn ( 583532 )
          But revolutions and wars and things never happen just like that. You can't start a revolution from nothing, despite of what some have said.

          Every revolution is preceeded by years of tensions quietly building up. But I don't think it is the sunspots that trigger the real action. You can't usually even really tell when some war or revolution actually begun. I mean, yes, you can say that WWII started on September 1st, 1939, but this is really only just the date when Germany attacked Poland. What about the even
          • I mean, yes, you can say that WWII started on September 1st, 1939, but this is really only just the date when Germany attacked Poland. What about the events before? Or after? Yes, there was a war, but when did it begin?

            You've made a good point about the start of hostilities not necessarily being the start of war.

            As for WWII, my contention is that it started in 1931 when Japan attacked China. The September 1, 1939 date is when Poland was invaded by Germany and the Soviet Union. Then again, Jerry Pournell

    • People tend to reproduce in 20 year cycles. Maybe that has something to do with it?

    • Re:Wars and revolutions (Score:2, Insightful)

      by 56ker ( 566853 )
      There is none - people look for patterns where there aren't any. :)
    • So remember students and politicians, next time you want to give a rousing 'go to war' speach or paint a placard and protest war, it's just the spots talking.
    • Always remember, correlation =! causality.
    • If you're searching for the motive force behind wars, I think you're looking at too long a period of fluctuation in the 11-year sunspot cycle, because the relevant periodicity is a 24-hour one.

      The sun goes down, people engage in a spot of fun hanky panky, a politician is born, and you have wars. Pretty simple, very accurate, and as predictable as night follows day, which indeed it does.

      QED :-)
    • Here's a theory... Some evidence suggests that there's a link between global climate (ocean temperatures) and solar sunspot activity [nasa.gov]. This is known to affect floods [glaciermedicaled.com] and thus crop production. If you've got a population busy harvesting crops, then they're less likely to be motivated to start wars. Unemployment and poverty have been the major factors involved in starting wars.

      • Re:Wars and revolutions (Score:1, Funny)

        by Anonymous Coward
        "unemployment and poverty have been the major factors involved in starting wars."

        you forgot oil

  • As far South as WHERE? (Score:3, Insightful)

    by PingXao ( 153057 ) on Saturday November 22, 2003 @06:38AM (#7535599)
    With all those recent CMEs I've been scanning the skies at night for a couple of weeks now. At least the clear nights. I'm in the Northeast U.S. and I sure as hell didn't see any auroras. That was one of the things I was specifically looking for. I think the mention of visible auroras as far south as Florida is hogwash. Is that just something the OP made up for effect or did it actually somehow get that far south unnoticed by just about everyone in the Northeast?
    • Yes, it did actually make it that far. I have a friend who saw them easily in IN, and FL is hardly much further south.

      You can monitor current auroral activity here [noaa.gov].

      You probably failed to see the lights due to the intense light pollution on the eastern seaboard, which is also the reason why there are no major observatories in the eastern states.
      • That's the same site I was monitoring while the CMEs were hurtling our way last week. None of the blue shaded area in the graphic ever went any further south than where it is right now, which as best as I can make out is ~Roanoke VA. Whenever I checked it wasn't even as far south as it is now (maybe I should check tonight!) That graphic never showed anything remotely close to the 0.1 level over the NY area. I suppose you could be right about the light pollution thing. We did have 1 night of good viewin
        • If you have the chance, go to the north in the winter sometime. Perhaps on an Alaskan cruise near the end of the cruise season. You will see them in the continental states, but only when massive flares happen.

          If anything, their beauty is worth standing outside in sub-zero weather!
  • if only to the power and comms companies. Always useful to know more about what affects you.

    I'm not sure there's much they can *do* about solar flares though, I mean, talk about force of nature! Volumes of incandescent plasma the size of the planet being ejected are always going to be tough to deal with!

    Simon

  • Let me see... (Score:5, Insightful)

    by EvilTwinSkippy ( 112490 ) <yoda@nOSpAM.etoyoc.com> on Saturday November 22, 2003 @07:10AM (#7535656) Homepage Journal
    We have been monitoring the sun from satellites for 40 years. We have been observing the sun with telescopes for a little over 400 years. Our collective experience with the Sun might be about 40,000 years.

    And we think we really understand this object that has been generating energy for 4 billion years through a process we are only now developing theories about. Lets have some humility humanity!

    • I agree. Imprecise language, especially when used in science, is horrible.

      Key parts of the text would be better written
      It has been observed over several cycles that the peak of solar activity trail trails the sunspot cycle peak...
      and
      ... but this BBC article appears to provides a hypothesis of how.

      This would more clearly indicate that we have made observation that provide a possible cause and have developed a theoretical link between he cause and effect. Furthermore, the hypothesis can be used to pr

    • but that hasn't stopped some people from claiming that we have managed to cause "global warming". We aren't accurate 30 days out, nor a quarter, yet we are expect to believe we can be accurate 50 to 100 years? We cannot seem to predict the ozone hole! (which isn't there right now...)

      One volcanoe, a bunch of wildfires, or a hurricane does things to the environment we can lay little claim in judging to their fullest extent yet we claim to know our effect?

      As you put it, we don't know jack about that giant
      • We can't predict the WEATHER, as in the day to day flow of air, all that well, but we are pretty good at predicting the CLIMATE, as in the general pattern of temperature and moisture.

        Global warming is definitely more related to climate than weather.

        • Correction: we can't predict the weather, and we simply don't know whether or not we can predict the climate. Your statement is completely ridiculous; we've been seriously trying to predict the climate for, what ten years? These are predictions that are supposed to be for decades or centuries into the future. None of these things have come remotely close to being tested yet. The closest any of them have come to being tested is running several different simulations on the same data and seeing how well they m
          • None of these things have come remotely close to being tested yet. The closest any of them have come to being tested is running several different simulations on the same data and seeing how well they match.

            We can and have compared models to historical records, with good matches (i.e. start the model with historical data up to AD1000, then run for the next 500 years and compare the model output with the actual historical record) . That's prehaps not a pure "prediction", but a model that accurately descri

            • Historical data is nice, but not terribly fine-grained. I don't think a climate model based on once-a-year temperature and precipitation records like you find in glaciers is going to be all that great. Even disregarding that, it's like successfully predicting the weather for ten weeks, and then saying everything works and you can certainly predict the weather for one more week with good accuracy. Lots of things could change in that last week. We have lots of indications that climate can change rapidly as we
              • we still don't know why it's happening, second, we have no idea if it's normal, and third, we have no idea if it's a good thing or a bad thing.If you can point me to some good, reliable data that shows conclusively that it's overwhelmingly caused by human activity, and it's going to be a bad thing when it arrives, I'd love to see it.

                Go read the National Academy of Sciences Report [nas.edu] from their working group on climate change. Keep in mind that any politically sensitive report written by a committee of scien

        • We can't predict the WEATHER, as in the day to day flow of air, all that well, but we are pretty good at predicting the CLIMATE, as in the general pattern of temperature and moisture.

          Actually, we are no better at predicting climate than weather. What looks like "greater accuracy" in predictions is simply the effect of scale. Weather and climate are, essentially, the same things on different scales. "Weather" happens in smaller areas over shorter periods of time. Predicting that the climate on a scale of m

          • Actually, we are no better at predicting climate than weather. What looks like "greater accuracy" in predictions is simply the effect of scale. Weather and climate are, essentially, the same things on different scales.

            No, that is not true. Weather is a dynamical phenomenon that is "chaotic" in the sense that the variables are exponentially dependent on initial conditions. Climate is the set of variables that describe the statistical behaviour of the weather. There is a big difference: we may not be able

            • No, that is not true. Weather is a dynamical phenomenon that is "chaotic" in the sense that the variables are exponentially dependent on initial conditions. Climate is the set of variables that describe the statistical behaviour of the weather.

              Your understanding of the difference between climate and weather are in error. Climate is no less chaotic than weather because it is nothing more than aggregate (usually seasonal) weather data collected over a period of years. Climate is made out of weather.

              There

              • Climate is no less chaotic than weather because it is nothing more than aggregate (usually seasonal) weather data collected over a period of years.

                Again, climate is the set of variables that describe the statistical properties of the weather. Things like the mean and variance of temperature, rainfall, wind etc etc. It could also include the probability distribution of those variables. Even if you can't say exactly what the temperature in LA will be next month, you can give a probability distribution for

        • Okay, we can't explain the pattern of ice ages, we don't know what caused the Medieval Warm Period or the Little Ice Age, and we have yet to find a generally accepted explanation as to why upper troposphere temperature reading badly conflict with surface temperature readings, in defiance of all theoretical models.

          Yet, despite the fact that we can't explain climate, you think we can predict it?
    • speaking of monitoring, I just came across a site for any amateur astronomers who want to read what others are observing...

      http://www.observingthesky.org [observingthesky.org]

      Great site, seems to have a fair amount of information regarding the recent solar flares also.

    • Yeah, but big and shiny as it might be, the sun isn't nearly as complex as for example a fruit fly or a nematode.

      Of course, we are a long way from really understanding them.

  • Aurora is so beatiful and here is the HOWTO (Score:5, Informative)

    by Pingo ( 41908 ) on Saturday November 22, 2003 @07:19AM (#7535673)
    This very radiant natural lightshow is mostly enjoyed by people living far north where there is no streetlights obscuring the show.

    However in recent weeks there has been very strong aurora far south and if you would like to know when it's time for a great show, check this NASA webpage http://sec.noaa.gov/rt_plots/satenv.html

    The last plot with the 'Estimated Kp' is what to look for. When the number is around 9, then there is great Aurora to be seen if the sky is clear and no streetlights around.

    If you live far north, then you might see Aurora with lesser values of this Kp index. Red bars in the plot is needed however. //Pingo

    • check this NASA webpage http://sec.noaa.gov/rt_plots/satenv.html. The last plot with the 'Estimated Kp' is what to look for. When the number is around 9, then there is great Aurora to be seen if the sky is clear and no streetlights around.

      Even when the Kp is 9 or 10, aurora are not guaranteed. A previous poster [slashdot.org] had a link to a much better page [noaa.gov], which is an actual map of the aurora over the Northern hemisphere. That page is linked from this page [noaa.gov], which has links to both hemispheres, 'movies', higher-res

  • Small Office Home Office? (Score:2, Funny)

    by Anonymous Coward
    They're stll using a SOHO satellite? They could have learned a lot more if they had upgraded to a larger enterprise class solution. Hmm, enterprise .. catchy!

  • A Basic Knowledge of Sunspots (Score:5, Informative)

    by Anonymous Coward on Saturday November 22, 2003 @08:12AM (#7535774)
    Those who live and work in the high latitudes - such as in those few sources the US has where there is oil pay a lot of attention to sunspots. Communication disruptions are the biggest problem. Much more rare are power failures - but they have been known to bring down entire power grids. In 1986, British Columbia had a huge power failure. Not all the evidence is in about the recent East coast power outage [slashdot.org] - They still haven't determined what caused the lines to overheat in the first place - The Ohio company appears to have made mistakes - but they may also just have been trying to keep up with too much demand on the grid all day. Solar flares affect the grid in unexpected ways. That's one of the many reasons they're being watched so closely.

    I've probably seen the aurora 300-400 times. It is one of the beautiful things to my eye in nature. If it's out, in my experience - it can change in 5 minutes time from close to nothing to wild. Photos don't do it justice - but this site [nasa.gov] has some movies too, that give just a slight feel of it.

    The BBC article is very simplified - A fairly new technique - called "helioseismic holography" allows astronomers to actually 'look through' the sun to image the magnetic fields of very large sunspots like the present pair (they occur in pairs - corresponding to a north and south magetic pole).
    This present sunspot pair is the largest we've ever measured.

    The particles themselves don't really emit the light - "the electrons that cause auroras do not come directly from the Sun" [nasa.gov]

    Sunspots can be seen under certain lighting conditions when the sun is rising or setting even with the naked eye.
    Chinese astonomers recorded them long before they were one of the first things that we're recorded by the inventors and early users of the telescope.

    Sunspots - a reduced number of them - have been correlated with cooler weather trends. [ucsd.edu]

    There was about a 70 year period of fairly recent time - 1645 -1715 that apparently saw no auroras - even at high latitudes - kids thought they were mythical stories by the time they appeared.

    The solar flare a few weeks ago was the strongest we've ever measured, and we can expect to see more [spaceweather.com] as that same pair of sunspots rotates around to face Earth.

    The solar eclipse will be tomorrow - there will be some great photos that will come out in the next few days.
    • Umm, all the evidence *IS* in on the recent East coast power outage. You could have gone to the NOAA website [noaa.gov] and pulled up the data on August 14th [noaa.gov], and seen that there were no events, and only an early morning warning that day (yes, I know the page is in GMT, blackout was at 16:10 EPT = 21:10 GMT)... it takes about a K-6 on the scale before the utilities even start considering conservative ops, and we check real-time DC amp ratings at various stations for actual indications of SMD events.
    • I come from a dark part of Canada and I remember a winter, about '96 or '97, that had awesome northern lights almost every night.

      On a few nights, you could hear them making a crackling sound, keeping time with the visuals. It was one of the most eerie things I've experienced.

      Anyone else heard the aurora?

      • This is a suprisingly common phenomenon, which many people have tried to explain to some avail.

        The key lies in noticing that the sounds are, as you mention, timed perfectly with the visuals. As the aurora occurs about 60 miles up, if this were really the sound of the aurora itself it would come at least 5 minutes later. (5 secs per mile, at least at STP, which it isn't that high up).

        So...current theory has it that the aurora is producing radio waves which travel the speed of light, which produce electric
        • One thing that might confirm this - the sounds that you have heard - did they occur on very dry nights, e.g. when it's extremely cold out?

          That's exactly right; -30 degrees C in a stubble field on the prairies. Absolute humidity of approximately zero.

          • I worked in the Arctic - I listened for this since I read of this.
            I wasn't sure... One night - very cold - like described, but there was little around to interfere with - it was pretty much hard packed snow - and I could only get a little away from camp where it was noisy.
            Inconclusive.
            I just heard from someone who said they *heard* the recent aurora on a PA system.
  • It does not orbit Earth.
  • but this BBC article appears to explain why.
    Which roughly translates as:

    I didn't actually read the article, just looked at the pretty pictures and guessed it had something to do with suns and stuff. Or maybe with 20th century impressionism.

  • An anonymous reader writes

    Is he allowed to do that?

  • I'm not solar physicist, but it seems like the article is attributing intention to the sun, as if it "wants" to "shed its magnetic skin", like it was a purposeful way of "dealing" with the increasing tension.
    • What's wrong with a little anthropomorphizing if you don't take it too seriously? Haven't you ever said, when working on a slow computer, "well, it's got to think about that for a while" or "god, it's being stupid today"?
      • What's wrong with a little anthropomorphizing if you don't take it too seriously? Haven't you ever said, when working on a slow computer, "well, it's got to think about that for a while" or "god, it's being stupid today"?

        Now, I'm all for anthromorphizing in those two examples...it's just another way of summarizing the observed behavior. But if you said "this computer HATES me, that's why it's messing up", then I would think you were being silly. With this article, it's the latter case...implying it's ex
  • Another cool sun photo, of the suns corona [nasa.gov]. The short paragraph also discusses the total solar eclipse tomorrow, sorry for most of us it is southern hemisphere only.

  • Sun:Earth correlation? (Score:2, Interesting)

    by Anonymous Coward

    Now that we have this theory relating the sun's surface/coronal activity to the reversing of its magnetic field with a given periodicity, what say we look for a possible analog with the earth. Might there be a relation between surface/atmospheric events on the earth and the reversing of it's magnetic poles (eg. volcanic activity increase, polar ozone hole size increase timing relative to a pole reversal event?) Any armchair scientist care to correlate the solar pole reversal with the longer period of the

  • these sunspots (Score:3, Informative)

    by ShadowRage ( 678728 ) on Saturday November 22, 2003 @12:26PM (#7536800) Homepage Journal
    were visible with the naked eye a few weeks back when we had the fires here in southern california, the smoke was so thick, you could still see the sun, but not in its right glory, you could see the big sunspots as shown here: http://sohowww.nascom.nasa.gov/sunspots/

    it was interesting to say the least..

  • Accelerated Solar Aging? (Score:2, Interesting)

    by Anonymous Coward
    So with this new understanding of regular ejections of billions of tons of matter from the sun, does anyone know if scientists are changing their minds about how long the sun will still last?

    The reason I ask is because apparently gravity created by the mass of the sun is roughly equivalent to the outward expansive force caused by the fusion reaction going on inside. If the mass is decreasing more rapidly because of these regular shedding events, I'd expect the ETA of our sun going red-giant and consuming t
    • Umm, No. Let's do a couple back-of-the-envelope calculations, shall we?

      OK, assuming the Sun has a density of 1 (which is actually fairly close overall) and a radius of 350,000,000 m:

      Mass = Density * Volume
      = (1000kg/meter-cubed) * (4/3*Pi*(r-cubed))
      = 1000kg * 3.14159 * 1.333 * (350,000,000m)^3
      = 1.8 x 10^29 kg

      Now, I'm not sure which ton they're using, but since this is a BBC article, I'm assuming they mean a megagram.

      So, losing a billion tons (a trillion kg) would be about:
      10^12kg/3.8 x 10^20 kg = 5.6 x
  • I've heard that they say "skips rolling" when this type of weather is happening. Can anybody confirm this?

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