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Last Post 3/13/2009 8:41 AM by  Paulett Liewer
Solar Activity
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3/12/2009 10:39 AM

    I like Astronomy as a hobby, and many of the web sites have been talking about solar activity lately (or lack there of). I was wondering what the professionals think. It sure seems to be a very weak cycle. When was the last time we had so few sunspots for such a long period? Ever? What will the result be for us on Earth?

    Some people have said this year they can only see an aurora even high in Canada and Alaska once in a while, and not almost every day like normal. If that also due to the lack of solar activity?

    Tags: aurora, Sun Spots Activity

    Kris Sigsbee

    Basic Member

    Basic Member

    3/12/2009 2:15 PM


    I haven't been following the solar cycle very closely, so I'm not sure how much longer than normal the period of low activity may or may not have been. From what I can find, it looks like we are currently at a 50-year low in solar activity (see I think we are supposed to be coming out of solar minimum now , so it is a little bit odd that there are no sunspots at the moment.

    Several years ago, I spent some time up in Alaska working on data from a satellite called Fast Auroral SnapshoT (or FAST). We worked at the Poker Flat Research Range, which is near Fairbanks, Alaska. I was there around 1998ish (my memory's not working so well today), so the Sun was probably starting to come out of solar minimum. Most of the time, we could see what scientists would call a diffuse auroral arc that remained fairly stationary in the sky. We did get some nice auroral displays, but I have to say I don't think we had these every day - maybe only every 2-3 days. Even at high latitudes, you won't expect to see bright aurora unless the magnetosphere is somewhat disturbed by changes in the solar wind or by solar activity. In any case, you can blame the low auroral activity on the Sun.


    Emilia Kilpua

    New Member

    New Member

    3/13/2009 4:08 AM
    I’m working at the moment with the STEREO mission that was launched in late 2006, just on the brink of the solar minimum. It has been quite disappointing sometimes that there have been so few good coronal mass ejection (CME) events due to the low solar activity… And the activity seems to continue low although several sunspot groups from solar cycle 24 have emerged since early 2008. So hopefully, the Sun will get more active soon, but since predicting the solar cycle is very difficult we can only wait and see.. You can also check the link from that discuss about the current solar minimum and how it is related to the previous low activity periods.

    At solar minimum the magnetic storms at the Earth, when auroras are seen, are mainly caused by high speed solar wind streams from the solar coronal holes. High speed streams cause mainly small and moderate magnetic storms and the associated auroral activity occurs at high latitudes. The large storms, when aurora are seen at the lower latitudes as well, are nearly all caused by CMEs that are very rare during solar minimum. During 2007 and 2008 there has not been a single large magnetic storm. It is interesting if the high latitude activity caused by solar wind streams has also been low during this solar minimum

    Paulett Liewer

    Basic Member

    Basic Member

    3/13/2009 8:41 AM

    Hi Anonymous,

    There have been times before when then Sun showed so little activity. The most famous is the Maunder Minimum. The effects at Earth of a period of low activity are very, very subtle and not well understood. During the Maunder minimum, norther Europe got colder, but we are not sure why..When the Sun is less activity, more Cosmic Rays (energetic particles from outside our solar system) get into Earth's atmosphere. We are seeing this now as well. But we are not sure how this affects Earth's weather patterns. It is a very active area of research.

    And activity causes some of the aurora, so the fact that there a few aurora is definitely due to less solar activity. THAT we understand...


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