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The Little Ice Age
By DR. TONY PHILLIPS IIllustration by BRADY JACKSON “The surprising result of these longrange predictions is a rapid decline in solar activity, starting with cycle number 24. If this trend continues, we may see the Sun heading towards a “Maunder” type of solar activity minimum - an extensive period of reduced levels of solar activity. It can get worse than a repeat of the Dalton Minimum. Ken Schatten is the solar physicist with the best track record in predicting solar cycles. His work suggests a return to the advancing glaciers and delayed spring snow melt of the Little Ice Age, for an indeterminate period.”
Sun to Earth The effects that the Sun’s magnetic field has on Earth are of a kind that seldom affect the life of the average person. They include: the harmless Northern and Southern Lights (aurorae), disruption of long-distance short-wave radio communications, breaks (on rare occasions) in certain long electrical wires or in electrical systems, cyclical expansion of the very dilute outermost layers of the Earth’s atmosphere, and higher but certainly not life-threatening levels of radiation.
extended from around 1350 to 1850, and some of its coldest periods roughly coincide with the times of decreased solar activity during the Maunder Minimum. Scientist are uncertain precisely what link, if any, might exist between the altered behavior of the Sun and the disruption of Earth’s climate. There is also considerable debate as to the geographical extent of the Little Ice Age; some scientists think it was a worldwide phenomenon, while others think its effects were felt mainly in Europe and some parts of North America.
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6 A Solar Prominence A solar prominencce (also known as a filament) is an arc of gas that erupts from the surface of the Sun. Prominences can loop hundreds of thousands of miles into space. Prominences are held above the Sun’s surface by strong magnetic fields and can last for many months. At some time in their existence, most prominences will erupt, spewing enormous amounts of solar material out into space.
Sunspots are temporary phenomena on the surface of the Sun (the photosphere) that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection, forming areas of reduced surface temperature.
The Sun
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1 Sunspots
and its atmosphere consist of several zones or layers. From the inside out, the solar interior consists of the core, the radiative zone, and the convection zone. Because astronomers cannot see inside the sun, they have learned about the solar interior indirectly. Part of their knowledge is based on the observed properties of the sun as a whole. Some of it is based on calculations that produce phenomena in the observable zones.
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2 The Photosphere The photosphere is the surface of the Sun. This is the region where light from the interior finally reaches space. The temperature is 6000 K, which is the same as 5,700 degrees C.
The inner core is the heart of the Sun, where the temperatures and pressures are so high that nuclear fusion reactions can happen. All of the energy coming from the Sun originates from the core.
3 The Inner Core
5 The Convection Zone The convection zone is the region of the Sun where heat from the core is transferred through convection. Warm columns of plasma rise to the surface in columns, release their heat and then fall back down to heat up again.
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4 The Radiation Zone The radiation zone is the region of the Sun where energy can only be transferred through radiation. It can take a single photon 200,000 years to get from the core, through the radiative zone, out to the surface and into space.