The Solar Cycle
Solar maximum is the term for the maximum in solar
activity that takes place approximately every eleven years;
solar minimum is the lowest point of solar activity.
The last solar maximum was in 2001.
Solar events can interact and interfere with each other, creating a very complex system. Their frequency varies with time. The smaller flares tend to follow the eleven year cycle and peak at several tens of flares per day. The largest flares usually occur only a few times during solar maximum. Sunspots increase with solar maximum, and are relatively rare during solar quiet times. Coronal holes do not last as long during solar maximum. Monthly averages of the sunspot numbers show that the number of sunspots visible on the Sun waxes, during solar maximum and wanes, solar minimum with an approximate 11-year cycle. Image courtesy of David Hathaway, NASA MSFC.
More about sunspots and the solar cycle... Solar Cycles in the News:
July 20, 2009: Is
the Sun missing its spots? -- NY Times July 20, 2009: Solar cycle linked to global climate, drives events simlar to El Nino and La Nina -- Astronomy.com July 6, 2009: Sunspot activity ramping up out of deep slumber -- Scientific American June 17, 2009: Mystery of the missing sunspots, solved? -- Science@NASA June 12, 2009: Solar activity to have lowest high in 90 years? -- National Geographic June 4, 2009: Sunspots on a cloudy day -- APOD May 29, 2009: New solar cycle prediction -- Science@NASA May 22, 2009: Giant balloon flying high over Atlantic to catch cosmic rays -- Science Daily May 15, 2009: STEREO spies first major activity of Solar Cycle 24 -- NASA May 8, 2009: Sun entering weakest cycle since 1928 -- Science News May 7, 2009: Solar activity starting to perk up? -- Scientific American May 4, 2009: Sun oddly quiet -- hints at next "Little Ice Age"? -- National Geographic April 6, 2009: Serene Sun -- HEAPOW April 1, 2009: How low can it go? Sun plunges into the quietist solar minimum in a century -- NASA April 1, 2009: Deep solar minimum -- Science@NASA December 15, 2008: Space has never been closer -- NASA December 10, 2008: Sun's cycles can forecast floods, drought? -- National Geographic November 14, 2008: Solar cycle variations in observed galactic cosmic ray composition -- ACE News November 7, 2008: The Sun shows signs of life -- Science@NASA October 13, 2008: Spotless -- HEAPOW September 24, 2008: Active Region 1002 on an unusually quiet Sun -- APOD July 11, 2008: What's wrong with the sun? (Nothing) -- Science@NASA June 9, 2008: Sun goes longer than normal without producing sunspots -- Science Daily March 31, 2008: Old solar cycle returns -- ESA March 31, 2008: Cycle 23 redux -- HEAPOW February 6, 2008: A sunspot in the new solar cycle -- APOD January 14, 2008: Ulysses spacecraft flies over Sun's north pole -- NASA JPL January 14, 2008: SOHO: The new solar cycle starts with a 'bang' -- ESA January 7, 2008: 'Maverick' sunspot heralds new solar cycle -- New Scientist December 14, 2007: Is a new solar cycle beginning? -- Science@NASA December 3, 2007: A complete solar cycle from SOHO -- APOD November 14, 2007: Regional variation in warming from Sun during solar cycle shown by satellite -- Science Daily August 31, 2007: Celebrating 10 years of ACE in space -- ACE News July 11, 2007: Study clears Sun of global warming -- Australian Broadcasting Company May 25, 2007: Astrophysicists find fractal image of Sun's 'storm season' imprinted on solar wind -- EurekAlert! April 27, 2007: NOAA announces next solar storm cycle will likely start next March -- EurekAlert! April 25, 2007: The quest to predict the next space "hurricane" season -- NASA GSFC February 23, 2007: Sol sister -- SpaceDaily Solar Cycle Activities
Grades 7 - 9: The Sunspot Cycle -- NASA IMAGE
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