Solar Activity and the Solar Cycle

The Sunspot and Solar Activity Cycle

The Sun is not just a big bright ball. It has a complicated and changing magnetic field, which forms things like sunspots and active regions. The magnetic field sometimes changes explosively, spitting out clouds of plasma and energetic particles into space and sometimes even towards Earth. The solar magnetic field changes on an 11 year cycle. Every solar cycle, the number of sunspots, flares, and solar storms increases to a peak, which is known as the solar maximum. Then, after a few years of high activity, the Sun will ramp down to a few years of low activity, known as the solar minimum. This pattern is called the “sunspot cycle”, the “solar cycle”, or the “activity cycle”.

The Sunspot and Solar Activity Cycle

(credit: SOHO (ESA & NASA))


  1. […] Leave a Comment A few weeks ago 3 groups of solar scientists released a joint press release at the 2011 meeting of Solar Physics Division (SPD) of the American Astronomical Society. Each group presented a unique set of solar observations, which together they interpreted as showing the Sun is headed towards a period of extended low activity not solar maximum. There has been very little noticeable solar activity since the exiting event of June 7, 2011. Could this mean that those 3 groups of solar scientists are correct? Maybe not… (For more on solar activity and the solar cycle.) […]

  2. Chuck Rossier says:

    In the early 70’s I was informed by scientists at Harvard and MIT that the 11 year solar cycle was actually only a half cycle and the full cycle was approximately 22 years. Have observations and statistics since then eliminated the theory of the 22 year cycle?

  3. Ken says:

    Just came from a lecture about sun hibernation by John L Casey. he talked about the ” cold ” sun. Do you suscribe to his ideas? I thought his reasoning and charts were very sound .

  4. marj darling says:

    Do you still believe the sun is a nuclear fusion reactor, rather than receiving its energy via Birkeland currents?

Leave a Reply

Your email address will not be published. Required fields are marked *