# Solar minimum

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Solar_minimum
> Markdown URL: https://mediated.wiki/source/Solar_minimum.md
> Source: https://en.wikipedia.org/wiki/Solar_minimum
> Source revision: 1323959941
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Regular period of least solar activity

For broader coverage of this topic, see [Solar cycle](/source/Solar_cycle).

Three recent solar cycles

**Solar minimum** is the regular period of least solar activity in the [Sun](/source/Sun)'s 11-year [solar cycle](/source/Solar_cycle). During solar minimum, [sunspot](/source/Sunspot) and [solar flare](/source/Solar_flare) activity diminishes, and often does not occur for days at a time. On average, the solar cycle takes about 11 years to go from one solar minimum to the next, with duration observed varying from 9 to 14 years. The date of the minimum is described by a smoothed average over 12 months of sunspot activity, so identifying the date of the solar minimum usually can only happen 6 months after the minimum takes place.

Solar minimum is contrasted with the [solar maximum](/source/Solar_maximum), when hundreds of sunspots may occur.

## Solar minimum and solar maximum

Solar minima and maxima are the two extremes of the Sun's 11-year and 400-year activity cycle.[1] At a maximum, the Sun is peppered with [sunspots](/source/Sunspots), [solar flares](/source/Solar_flares) erupt, and the Sun hurls billion-ton clouds of electrified gas into space. Sky watchers may see more auroras, and space agencies must monitor radiation storms for astronaut protection. Power outages, satellite malfunctions, communication disruptions, and GPS receiver malfunctions are just a few of the things that can happen during a solar maximum.[2]

At a solar minimum, there are fewer [sunspots](/source/Sunspots) and [solar flares](/source/Solar_flares) subside. Sometimes, days or weeks go by without a spot.

## Predicting solar minimum cycles

Their non-linear character makes predictions of solar activity very difficult.[3] The solar minimum is characterized by a period of decreased solar activity with few, if any, [sunspots](/source/Sunspots). Scientists from the National Center for Atmospheric Research (NCAR) also developed a computer model of solar dynamics ([Solar dynamo](/source/Solar_dynamo)) for more accurate predictions and have confidence in the forecast based upon a series of test runs with the newly developed model simulating the strength of the past eight solar cycles with more than 98% accuracy.[4] In hindsight the prediction proved to be wildly inaccurate and not representative of the observed sunspot numbers.[5]

During 2008–09 NASA scientists noted that the Sun is undergoing a "deep solar minimum," stating: "There were no sunspots observed on 266 of [2008's] 366 days (73%). Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008. Sunspot counts for 2009 dropped even lower. As of September 14, 2009 there were no sunspots on 206 of the year's 257 days (80%). Solar physicist Dean Pesnell of the Goddard Space Flight Center came to the following conclusion: "We're experiencing a very deep solar minimum." His statement was confirmed by other specialists in the field. "This is the quietest sun we've seen in almost a century," agreed sunspot expert David Hathaway of the National Space Science and Technology Center NASA/Marshall Space Flight Center.[6] However, the activity is still at a higher level than at a grand solar minimum.

## Grand solar minima and maxima

Main article: [Solar cycle](/source/Solar_cycle)

Grand solar minima occur when several solar cycles exhibit lesser than average activity for decades or centuries. Solar cycles still occur during these grand solar minimum periods but are at a lower intensity than usual. The grand minima form a special mode of the solar dynamo operation.[7]

400 year history of [sunspot numbers](/source/Wolf_number).

Solar minimum and maximum events with approximate dates Event Start End Homeric Minimum[8] 950 BC 800 BC Roman Warm Period 250 BC AD 400 Medieval maximum 1 (see Medieval Warm Period) 950 1040 Oort minimum (see Medieval Warm Period) 1040 1080 Medieval maximum 2 (see Medieval Warm Period) 1100 1250 Wolf minimum 1280 1350 Spörer Minimum 1450 1550 Maunder Minimum 1645 1715 Dalton Minimum 1790 1820 Modern Maximum 1914 2008

A list of historical Grand minima of solar activity[9] 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.

## See also

- [Active region](/source/Active_region)

- [List of solar cycles](/source/List_of_solar_cycles)

- [Maunder Minimum](/source/Maunder_Minimum)

- [Solar cycle](/source/Solar_cycle)

- [Solar cycle 24](/source/Solar_cycle_24)

- [Solar maximum](/source/Solar_maximum)

## References

1. **[^](#cite_ref-1)** Moussas, X.; Polygiannakis, J. M.; Preka-Papadema, P.; Exarhos, G. (2005). "Solar cycles: A tutorial". *Advances in Space Research*. **35** (5): 725–738. [Bibcode](/source/Bibcode_(identifier)):[2005AdSpR..35..725M](https://ui.adsabs.harvard.edu/abs/2005AdSpR..35..725M). [doi](/source/Doi_(identifier)):[10.1016/j.asr.2005.03.148](https://doi.org/10.1016%2Fj.asr.2005.03.148).

1. **[^](#cite_ref-2)** ["NOAA Space Weather Scales Page Has Changed"](http://www.swpc.noaa.gov/NOAAscales/). *noaa.gov*.

1. **[^](#cite_ref-3)** Petrovay, Kristof (2010). ["Solar Cycle Prediction"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4841181). *Living Reviews in Solar Physics*. **7** (1): 6. [arXiv](/source/ArXiv_(identifier)):[1012.5513](https://arxiv.org/abs/1012.5513). [Bibcode](/source/Bibcode_(identifier)):[2010LRSP....7....6P](https://ui.adsabs.harvard.edu/abs/2010LRSP....7....6P). [doi](/source/Doi_(identifier)):[10.12942/lrsp-2010-6](https://doi.org/10.12942%2Flrsp-2010-6). [PMC](/source/PMC_(identifier)) [4841181](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4841181). [PMID](/source/PMID_(identifier)) [27194963](https://pubmed.ncbi.nlm.nih.gov/27194963).

1. **[^](#cite_ref-4)** ["Scientists Issue Unprecedented Forecast of Next Sunspot Cycle – News Release"](https://web.archive.org/web/20060410174610/http://www.ucar.edu/news/releases/2006/sunspot.shtml). *ucar.edu*. Archived from [the original](http://www.ucar.edu/news/releases/2006/sunspot.shtml) on 2006-04-10.

1. **[^](#cite_ref-5)** ["Sunspot Number graphics"](http://sidc.oma.be/sunspot-index-graphics/wolfjmms.php). *oma.be*.

1. **[^](#cite_ref-science.nasa.gov_6-0)** ["Deep Solar Minimum – NASA Science"](https://web.archive.org/web/20090401172603/http://science.nasa.gov/headlines/y2009/01apr_deepsolarminimum.htm). *nasa.gov*. Archived from [the original](https://science.nasa.gov/headlines/y2009/01apr_deepsolarminimum.htm) on 2009-04-01.

1. **[^](#cite_ref-7)** C.-J. Wu; I. G. Usoskin; N. Krivova; G.A. Kovaltsov; M. Baroni; E. Bard; S.K. Solanki (2018). "Solar activity over nine millennia: A consistent multi-proxy reconstruction". *Astronomy and Astrophysics*. **615**: A93. [arXiv](/source/ArXiv_(identifier)):[1804.01302](https://arxiv.org/abs/1804.01302). [Bibcode](/source/Bibcode_(identifier)):[2018A&A...615A..93W](https://ui.adsabs.harvard.edu/abs/2018A&A...615A..93W). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201731892](https://doi.org/10.1051%2F0004-6361%2F201731892). [S2CID](/source/S2CID_(identifier)) [119376474](https://api.semanticscholar.org/CorpusID:119376474).

1. **[^](#cite_ref-SedimentStudy_8-0)** Celia Martin-Puertas; Katja Matthes; Achim Brauer; Raimund Muscheler; Felicitas Hansen; et al. (April 2, 2012). "Regional atmospheric circulation shifts induced by a grand solar minimum". *[Nature Geoscience](/source/Nature_Geoscience)*. **5** (6): 397–401. [Bibcode](/source/Bibcode_(identifier)):[2012NatGe...5..397M](https://ui.adsabs.harvard.edu/abs/2012NatGe...5..397M). [doi](/source/Doi_(identifier)):[10.1038/ngeo1460](https://doi.org/10.1038%2Fngeo1460).

1. **[^](#cite_ref-Usoskin07_9-0)** Usoskin, Ilya G.; Solanki, Sami K.; Kovaltsov, Gennady A. (2007). ["Grand minima and maxima of solar activity: new observational constraints"](http://cc.oulu.fi/~usoskin/personal/aa7704-07.pdf) (PDF). *Astron. Astrophys*. **471** (1): 301–9. [arXiv](/source/ArXiv_(identifier)):[0706.0385](https://arxiv.org/abs/0706.0385). [Bibcode](/source/Bibcode_(identifier)):[2007A&A...471..301U](https://ui.adsabs.harvard.edu/abs/2007A&A...471..301U). [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20077704](https://doi.org/10.1051%2F0004-6361%3A20077704). [S2CID](/source/S2CID_(identifier)) [7742132](https://api.semanticscholar.org/CorpusID:7742132).

## External links

- [Solar Cycle 25 peaking around 2022 could be one of the weakest in centuries](https://web.archive.org/web/20100324065925/http://science.nasa.gov/headlines/y2006/10may_longrange.htm)

- [New Insights on How Solar Minimums Affect Earth](https://www.jpl.nasa.gov/news/new-insights-on-how-solar-minimums-affect-earth) (NASA June 14, 2011)

v t e The Sun Internal structure Core Radiative zone Tachocline Convection zone Atmosphere Photosphere Supergranulation Granule Faculae Sunspot Ellerman bomb Chromosphere Plage Spicule Moreton wave Corona Transition region Coronal hole Coronal loop Coronal mass ejection Nanoflare Prominence Helmet streamer Supra-arcade downflows Alfvén surface Moss Variation Solar cycle List of solar cycles Active region Solar maximum Solar minimum Sunspot number Solar wind Solar wind turbulence Magnetic switchback Flare Helioseismology Heliosphere Corotating interaction region Current sheet Termination shock Heliosheath Heliopause Bow shock Related Eclipse In mythology and culture Lunar eclipse Heliophysics In culture Solar deity List Sun in fiction Solar activity Solar astronomy Solar dynamo Solar energy Solar neutrino Solar observation Solar phenomena Solar physics Solar radio emission Solar System Solar telescope Solar time Space climate Space weather Standard solar model Star Sunlight radiation Spectral class G-type main-sequence star Exploration Solar observatory List of heliophysics missions Category:Missions to the Sun Category

[Portals](https://en.wikipedia.org/wiki/Wikipedia:Contents/Portals):
- [Astronomy](https://en.wikipedia.org/wiki/Portal:Astronomy)
- [Stars](https://en.wikipedia.org/wiki/Portal:Stars)
- [Spaceflight](https://en.wikipedia.org/wiki/Portal:Spaceflight)
- [Outer space](https://en.wikipedia.org/wiki/Portal:Outer_space)
- [Solar System](https://en.wikipedia.org/wiki/Portal:Solar_System)

---
Adapted from the Wikipedia article [Solar minimum](https://en.wikipedia.org/wiki/Solar_minimum) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Solar_minimum?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.