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Solar Cycle

Last post Wed, Mar 11 2009 5:40 AM by Emilia Kilpua. 3 replies.
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  • Sun, Mar 8 2009 10:27 PM

    Solar Cycle

    What if the solar cycle stoped, what would happen?          Brittany F. (F.W.M.S.)

  • Mon, Mar 9 2009 9:20 AM In reply to

    Re: Solar Cycle

    Hi Brittany -- that is a very interesting question! The solar cycle has never stopped completely, but there have been extended periods of very low solar activity. One example of this is the Maunder minimum, between 1645 and 1715, when very few sunspots were seen. (For comparison, a "usual" solar cycle will have a period of lots of sunspots approximately every 11 years, which is "solar maximum". ) This time period coincided with the "Little Ice Age" where rivers froze in some parts of the world that didn't usually, and snow fields didn't melt as they usually did... So it is certainly possible that if the solar cycle stopped, climate on Earth would be affected. Diminished solar activity means a decrease in the sun's ultraviolet radiation which impacts ozone formation in the Earth's stratosphere. Jet stream winds may also be impacted by the the less active, and thus dimmer Sun. However, climate can be very complicated, and it is possible that volcanos also played a role in the cooling period that includes the Little Ice Age -- see There's still a lot of work to be done in figuring out what happened during the Maunder minimum, and more generally, what effect the solar cycle has on the Earth's climate. cheers, Sarah
  • Tue, Mar 10 2009 3:09 PM In reply to

    Re: Solar Cycle

    The newest solar cycle supposedly just started. However the sun seems to have been rather "boring" lately, since the announcement of the beginning of the cycle. Is this typical? My solar filters are getting dusty.


    Jim C

  • Wed, Mar 11 2009 5:40 AM In reply to

    • Emilia Kilpua
    • Top 10 Contributor
    • Joined on Tue, Mar 11 2008
    • University of Helsinki, Finland
    • Posts 88

    Re: Solar Cycle

    Hi Jim,

    Solar Cycle 24 has really struggled to get started. The present solar minimum has been very deep and long when compared to the few previous solar minimum.  Year 2008 was the ‘blankest’ year in terms of sunspots in more than 50 years. And the weak activity seems to be still continuing.. As a consequence, geomagnetic activity has also been very minimal. There haven't been any big magnetic storms in 2007 and 2008. However, solar cycles with deep solar minimum have occurred before, e.g. in mid and early 1900s so when considering longer time periods deep minima have occured before.  And also there are periods like Maunder minimum when sunspots are extremely rare for several tens of years.

    The first sunspot group of cycle 24 was observed on January 2008 and more and more new cycle groups have appeared since 2008.Few links about the cycle 24 predictions:


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