Editing Solar maximum (section)

==Grand solar minima and maxima==
{{Main|Solar cycle}}
In addition to the ~11 year solar cycle, the intensity of the solar maxima can vary from cycle to cycle. When several solar cycles exhibit greater than average activity for decades or centuries, this period is labelled "Grand solar maximum".  Solar cycles still occur during these grand solar maximum periods, but the intensity of those cycles is greater. Likewise, extended periods in which the solar maximum is lower than average are labeled "grand solar minima". Some researchers suggest that grand solar maxima have shown some correlation with global and regional climate changes, although others dispute this hypothesis (''e.g.'', see [[Medieval Warm Period]]).

Following the advent of telescopic solar observation with Galileo's 1611 observations, the intensity of solar maxima is typically measured by counting numbers and size of sunspots; for periods previous to this, isotope ratios in [[ice core]]s can be used to estimate solar activity. The table below shows the approximate dates of some of the proposed solar minima in historical times.

[[Image:Sunspot Numbers.png|thumb|400 year history of [[Wolf number|sunspot numbers]].]]

{| class="wikitable"
|+ '''Solar minimum and maximum events and approximate dates'''
|-
! Event !! Start !! End
|-
| [[Homeric Minimum|Homeric minimum]]<ref name="SedimentStudy">{{cite journal | title=Regional atmospheric circulation shifts induced by a grand solar minimum | journal=[[Nature Geoscience]] |date=April 2, 2012 |display-authors=4 |author=Celia Martin-Puertas |author2=[[Katja Matthes]] |author3=Achim Brauer|author4=Raimund Muscheler |author5=Felicitas Hansen|author6=Christof Petrick |author7=Ala Aldahan|author8=Göran Possnert |author9=Bas van Geel |name-list-style=amp |volume=5 |pages=397–401 |bibcode = 2012NatGe...5..397M |doi = 10.1038/ngeo1460 | issue=6 }}</ref>  || 950BC || 800BC
|-
| Oort minimum  || 1040 || 1080
|-
| Medieval maximum || 1100 || 1250
|-
| Wolf minimum || 1280 || 1350
|-
| [[Spörer Minimum]] || 1450 || 1550
|-
| [[Maunder Minimum]] || 1645 || 1715
|-
| [[Dalton Minimum]] || 1790 || 1820
|-
| [[Modern Maximum]] || 1914 || 2008
|-
| Unspecified || 2009 || present
|}

A proposed list of historical Grand minima of solar activity<ref name="Usoskin07">{{Cite journal | first1=Ilya G.| last1=Usoskin | author-link=Ilya G. Usoskin| first2=Sami K.| last2=Solanki | first3=Gennady A.  | last3=Kovaltsov | title=Grand minima and maxima of solar activity: new observational constraints | journal= Astron. Astrophys. | volume=471 | issue=1 | pages=301–9 | url=http://cc.oulu.fi/~usoskin/personal/aa7704-07.pdf | doi=10.1051/0004-6361:20077704 | date=2007 | bibcode=2007A&A...471..301U|arxiv = 0706.0385 | s2cid=7742132 }}</ref> includes also Grand minima ca. 690 AD, 360 BC, 770 BC, 1390 BC, 2860 BC, 3340 BC, 3500 BC, 3630 BC, 3940 BC, 4230 BC, 4330 BC, 5260 BC, 5460 BC, 5620 BC, 5710 BC, 5990 BC, 6220 BC, 6400 BC, 7040 BC, 7310 BC, 7520 BC, 8220 BC, 9170 BC.