The enormous magnetic field of the sun dictates the solar cycle
, which includes sunspots, solar wind and ejection of fast-moving particles that sometimes hit Earth.
However it ends, the current solar cycle
will go down in the annals of astronomy as one of the most illuminating yet.
The necessary data to create these models are Total Solar Irradiance (TSI), UT1 and MSL time series containing oscillations near to the solar cycles
. The observed UT1 data cover almost 4 centuries and MSL data--240a.
Scientists will also keep their eye on the current cycle -- numbered Solar Cycle
24 -- because a polar switch at the north that is sooner than was expected also implies this may be a fairly small cycle in terms of the number of sunspots and amount of solar activity.
The streams begin each solar cycle
at high latitudes and move equatorward until the cycle ends, as shown above.
According to NASA, the second flare was the largest recorded in this solar cycle
Elsewhere, Mayans marked the end of the solar cycle
at Guatemala's Gran Jaguar Temple, while there was a bumper crowd at Stonehenge, where end of the world onlookers joined Druids in celebrating the winter solstice.
The evidence "all indicates that the next solar cycle
will be delayed by two to five years," but that a longer break is possible, says Dean Pesnell of NASA's Goddard Space Flight Center in Greenbelt, Md., who didn't participate in the studies.
The lengthening days of summer and the increase in activity as Solar Cycle
24 gets under way have produced some welcome results for observers of Sudden Ionospheric Disturbances (SIDs).
Predicting the intensity of the next solar cycle
has never been easy.