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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...
Back to Solar Activity
May 6, 2012: Climatic
effects of a solar minimum -- Eurekalert
April 20, 2012: Hinode
and SOHO paint an asymmetrical picture of the sun -- Eurekalert
April 19, 2012: Here comes solar
maxiumum -- NASA ScienceCasts
April 11, 2012: Interplanetary
turbulence during the recent protracted solar minimum -- ACE News
March 19, 2012: Solar
cycle abundance variations in corotating interaction regions --
ACE News
December 19, 2011: Dropping
coronal temperatures in the protracted Cycle 23-24 solar minimum
-- ACE News
October 27, 2011: Solar
cycle primer -- NASA
July 4, 2011: What's going on
with the sun? -- Physics World
June 15, 2011: Drop
in sun's activity expected -- Astrobiology
June 14, 2011: New
insights on how solar minimums affect Earth -- NASA
April 18, 2011: Slow
start to solar cycle -- Astrobiology
April 14, 2011: Solar
activity heats up -- Science@NASA
March 6, 2011: Solving
the mystery of the spotless sun -- Astrobiology
November 23, 2010: Anomalous
cosmic ray behavior at 1 AU during the unusual solar minimum --
ACE News
October 6, 2010: Sun's
impact on climate change overestimated? -- National Geographic
October 6, 2010: Declining
solar activity linked to recent warming -- Nature
August 26, 2010: Distant
star's sound waves reveal cycle simlar to sun -- NSF
August 12, 2010: Extended
period of lower solar activity linked to changes in sun's conveyor
belt -- NSF
June 9, 2010: Orange sun
simmering -- APOD
May 27, 2010: Solar
scientists agree that the sun's recent behavior is odd, but the
explanation remains elusive -- Scientific American
May 10, 2010: Large eruptive
prominence movie from SDO -- APOD
April 8, 2010: The Sun
erupts from its lengthy slumber -- ACE News
March 30, 2010: The Sun comes
back to life -- ESA
March 12, 2010: Solar
'current of fire' speeds up -- Science@NASA
February 26, 2010: A
quiet Sun won't save us from global warming -- New Scientist ( NASA's Global Climate Change website)
December 17, 2009: Quiet
Sun means cooling of Earth's upper atmosphere -- NASA
November 17, 2009: NASA's
Solar Dynamics Observatory investigates the Sun's cycle of highs and
lows -- NASA
November 12, 2009: Distant stars
shed light on the solar cycle -- Physics World
October 6, 2009: Sun
down: High-energy cosmic rays reach a Space Age peak -- Scientific
American
September 29, 2009: Space
radation hits record high -- New Scientist
September 28, 2009: Cosmic
rays hit space age high -- NASA
September 23, 2009: The Sun could be
heading into period of extended calm -- Physics World
September 17, 2009: More to
solar cycle than sunspots -- NSF
September 5, 2009: Stratosphere
cycles with the Sun -- Astrobiology
September 3, 2009: Are
sunspots disappearing? -- Science@NASA
September 2, 2009: Mount
Wilson Observatory: View from the mountaintop -- Astronomy.com
August 27, 2009: Connections
among solar cycle, stratosphere and ocean discovered -- NSF
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
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