Solar cycle 24Solar cycle 24 is the most recently completed solar cycle, the 24th since 1755, when extensive recording of solar sunspot activity began. It began in December 2008 with a minimum smoothed sunspot number of 2.2, and ended in December 2019. Activity was minimal until early 2010. It reached its maximum in April 2014 with a 23 months smoothed sunspot number of 81.8.
Solar cyclePeriodic change in the Sun's activity400 years of sunspot history, including the Maunder Minimum"The prediction for solar cycle 24 gave a smoothed sunspot number maximum of about 101 in the late 2013. The smoothed sunspot number reached 116.4 in April 2014. This will probably become the official maximum. This second peak surpassed the level of the first peak (98.3 in March 2012).
Solar flareA solar flare is a relatively intense, localized emission of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and other eruptive solar phenomena. The occurrence of solar flares varies with the 11-year solar cycle.
Modern MaximumThe Modern Maximum was found by Sami Solanki, Ilya G. Usoskin and colleagues as the period of unusually high solar activity which began with solar cycle 15 in 1914. It reached a maximum in solar cycle 19 during the late 1950s and may have ended with the peak of solar cycle 23 in 2000, as solar cycle 24 is recording, at best, very muted solar activity. Another proposed end date for the maximum is 2007, with the decline phase of Cycle 23.Maunder MinimumThe Maunder Minimum, also known as the "prolonged sunspot minimum", was a period around 1645 to 1715 during which sunspots became exceedingly rare. During the 28-year period 1672–1699 within the minimum, observations revealed fewer than 50 sunspots. This contrasts with the typical 40,000–50,000 sunspots seen in modern times over a similar timespan.
SunspotSunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. Sunspots appear within active regions, usually in pairs of opposite magnetic polarity. Their number varies according to the approximately 11-year solar cycle.
Solar OrbiterEuropean space-based solar observatoryESA isnignia (2020s) Cosmic Vision (Science Programme)← CheopsJuice →Living With a Star program← ParkerThe Solar Orbiter (SolO) is a Sun-observing probe developed by the European Space Agency (ESA) with a NASA contribution. Solar Orbiter, designed to obtain detailed measurements of the inner heliosphere and the nascent solar wind, also performs close observations of the polar regions of the Sun which is difficult to do from Earth.
Global Oscillations Network GroupThe Global Oscillation Network Group (GONG) is a worldwide network of six identical telescopes, designed to have 24/7 observations of the Sun. The network serves multiple purposes, including the provision of operation data for use in space weather prediction, and the study of solar internal structure and dynamics using helioseismology.
SunStar at the centre of the Solar SystemThe Sun is the star located at the centre of the Solar System. It is a massive sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies. It is the main source of energy for life on Earth.
Convection zoneA convection zone of a star is a layer which is unstable due to convection. Energy is primarily or partially transported by convection in such a region. In a radiation zone, energy is transported by radiation and conduction. Stellar convection consists of mass movement of plasma within the star which usually forms a circular convection current with the heated plasma ascending and the cooled plasma descending.
Scientific literatureLiterary genre The frontispiece for some early scientific literature published in the Philosophical Transactions of the Royal Society Part of a series onScience General History Literature Method Philosophy Branches Formal Natural Physical Life Social Behavioral Cognitive Applied Science studies & Society Communication Community Education Funding Policy Pseudoscience Scientist Science portal Outline Category Article indexes Glossariesvte Scientific literature encompasses a vast body of academic papers that spans various disciplines within the natural and social sciences.Sunspot numberThe Wolf number (also known as the relative sunspot number or Zürich number) is a quantity that measures the number of sunspots and groups of sunspots present on the surface of the Sun. Historically, it was only possible to detect sunspots on the far side of the Sun indirectly using helioseismology. Since 2006, NASA's STEREO spacecraft allow their direct observation.*As an Amazon Associate I earn from qualifying purchases.