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Solar Cycle 24 is the 24th solar cycle since 1755, when extensive recording of solar sunspot activity began.〔Kane, R.P. (2002). "(Some Implications Using the Group Sunspot Number Reconstruction )". ''Solar Physics'' 205(2), 383-401.〕〔(【引用サイトリンク】 url=http://www.spacetoday.org/SolSys/Sun/Sunspots.html )〕 It is the current solar cycle, and began on January 4, 2008, but there was minimal activity until early 2010. It is on track to be the Solar Cycle with the lowest recorded sunspot activity since accurate records began in 1750. ==Predictions== Prior to the minima between the end of Solar Cycle 23 and the beginning of Solar Cycle 24, there were essentially two competing theories about how strong Solar Cycle 24 would be. The two camps could be distinguished by those postulating the Sun retained a long memory (Solar Cycle 24 would be active) or whether it had a short memory (Solar Cycle 24 would be quiet). Prior to 2006, the difference was very drastic with a minority set of researchers predicting "the smallest solar cycle in 100 years." Another group of researchers, including one at NASA, were predicting that it "looks like its going to be one of the most intense cycles since record-keeping began almost 400 years ago." The delayed onset of high latitude spots indicating the start of Solar Cycle 24 led the "active cycle" researchers to revise their predictions downward and the consensus by 2007 was split 5-4 in favor of a smaller cycle.〔(【引用サイトリンク】url=http://www.swpc.noaa.gov/SolarCycle/SC24/Statement_01.html ) 〕 By 2012, consensus was a small cycle, as solar cycles are much more predictable 3 years after minima. In May 2009 the NOAA/Space Weather Prediction Center's Solar Cycle 24 Prediction Panel predicted the cycle to peak at 90 sunspots in May 2013.〔(【引用サイトリンク】title=Solar Cycle Progression )〕 In May 2012 NASA's expert David Hathaway predicted that current solar cycle would peak by the Spring of 2013 with about 60 sunspots.〔(【引用サイトリンク】 date = 9 January 2013 )〕 NASA also directly funded and used Ken Schatten's physics-based models,〔(【引用サイトリンク】publisher = GEOPHYSICAL RESEARCH LETTERS, VOL. 32, L21106, doi:10.1029/2005GL024363 )〕 which utilized a solar Dynamo model to accurately predicted the low sunspot count in cycle 24. This method has used the correlation between solar magnetic field strength at solar minimum to sun spot number at solar maximum to accurately predict the peak solar flux of each of the last three solar cycles. Careful comparison of Schatten's predictions with those of Hathaway will demonstrate the superiority of Schatten's predictions: they are accurate as soon as solar minima 5–6 years before solar max. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Solar cycle 24」の詳細全文を読む スポンサード リンク
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