Major Drop in Solar Activity Predicted

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The Sun viewed in visible light, at minimum phase (2006) and maximum phase (2001)
"Butterfly diagram" shows the position of sunspots over 12 solar cycles. Sunspots emerge over a range of latitudes centered on migratory jet streams that follow a clear pattern, trending from higher latitudes to lower latitudes on the Sun. The active latitudes are associated with mobile zonal flows or "jet streams" that vary through the cycle.
Mobile "jet streams" in the Sun migrate from the poles toward the equator as the solar cycle progresses. At left (solar minimum) the red jet streams are located near the poles. At right (solar maximum) they have migrated close to the equator. The jet streams are associated with the locations where sunspots emerge during the solar cycle, and are thought to play an important role in generating the Sun's magnetic field.
Latitude-time plots of jet streams under the Sun's surface show the surprising shutdown of the solar cycle mechanism. New jet streams typically form at about 50 degrees latitude (as in 1999 on this plot) and are associated with the following solar cycle 11 years later. New jet streams associated with a future 2018-2020 solar maximum were expected to form by 2008 but are not present even now, indicating a delayed or missing Cycle 25.
The coronagraph at Sunspot, NM records brightness of the visible corona in a green emission line from highly ionized iron, as a function of solar latitude.
Plots of coronal brightness against solar latitude show a "rush to the poles" that reflects the formation of subsurface shear in the solar polar regions. The current "rush to the poles" is delayed and weak, reflecting the lack of new shear under the photosphere. Note the graph depicts both north and south hemispheres overlaid into one map of solar magnetic activity, and that the patterns correspond with the butterfly diagram above.
Detailed image of a complex sunspot group shows dark, highly magnetized "umbras" and structured "penumbras".
Inset shows the effect used to measure the magnetic field strength: a splitting of a spectral line in the sunspot. Magnetic fields cause single spectral lines to split into a multiple components, and the amount of the split is determined by the field strength.
Average magnetic field strength in sunspot umbras has been steadily declining for over a decade. The trend includes sunspots from Cycles 22, 23, and (the current cycle) 24.