Solar Activity Cycle - Discovery Of The Activity Cycle, Cause Of The Activity Cycle
field magnetic sunspots sun
The solar activity cycle is the periodic, typically 11-year-long variation in the number of active features (for example, sunspots) visible on the Sun's apparent surface or in its atmosphere. Over a period of 11 years, the number of sunspots gradually rises from a low level, reaches a maximum near the midpoint of the cycle, and then declines to a minimum. Solar activity is governed by the sun's magnetic field, and one of the unsolved problems in astronomy is the origin of the regular changes in the magnetic field that drive the activity cycle.
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The most easily observed solar active features are sunspots, which are relatively cool regions on the sun's surface that appear as dark areas to viewers on Earth. Galileo Galilei (1564-1642) made some of the first telescopic observations of sunspots in 1610, but it was not until 1843 that the amateur astronomer Heinrich Schwabe noticed that the number of sunspots rose and fell in a cyclic f…
No one has yet fully explained the origin of the solar activity cycle. Astronomers have developed several possible scenarios, or models, that reproduce the general characteristics of the cycle, but the details remain elusive. One of the most well-known of these models was developed in the early 1960s by Horace Babcock. Unlike Earth, the Sun is made of gas, and this makes a big difference in how th…
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