Century Dictionary and Cyclopedia
- n. One of the dark patches, from 1,000 to 100,000 miles in diameter, which are often visible upon the photosphere. The central part, or umbra, appears nearly black, though the darkness is really only relative to the intense surrounding brightness. With proper appliances the umbra itself is seen to contain still darker circular holes, and to be overlaid by films of transparent cloud. It is ordinarily surrounded by a nearly concentric penumbra composed of converging filaments. Often, however, the penumbra is unsymmetrical with respect to the umbra, and sometimes it is entirely wanting. The spots often appear in groups, and frequently a large one breaks up into smaller ones. They are continually changing in form and dimensions, and sometimes have a distinct drift upon the sun's surface. They last from a few hours to many months. They are known to be shallow cavities in the photosphere, depressed several hundred miles below the general level, and owe their darkness mainly to the absorption of light due to the cooler vapors which fill them. Their cause and the precise theory of their formation are still uncertain, though it is more than probable that they are in some way connected with descending currents from the upper regions of the solar atmosphere. The spots are limited to the region within 45° of the sun's equator, and are most numerous in latitudes from 15° to 20°, being rather scarce on the equator itself. They exhibit a marked periodicity in number: at intervals of about eleven years they are abundant, while at intermediate times they almost vanish. The explanation of this periodicity is still unknown. Numerous attempts have been made to correlate it with various periodic phenomena upon the earth—with doubtful success, however, except that there is an unmistakable (though unexplained) connection between the spottedness of the sun's surface and the number and violence of our so-called magnetic storms and auroras.
- n. A freckle.
- n. A spot on leaves produced by excessive heat of the sun. Compare heliosis, 1.
“The dangers to the planet Earth are more from the coming sun-spot activity that is about to hit us in five to ten years, if not sooner.”
“It is singularly ironic that whereas warm-mongers try to ridicule sun-spot cycles as an influence on temperature increase, now that the upwards trend in temperature has ceased, they are turning to the unusual absence of such sun-spot activity as an excuse for the fact that global warming has indeed ceased.”
“For Wolfs information, which you might refer to NASA or Greenwich Observatory to confirm, it has been known for over a century that the Earths climate fluctuates in direct response to sun-spot activity, the so called "Maunder Cycle".”
“At the moment, there is a pronounced absence of the usual increase in sun-spot activity expected at this point in the cycle, which is expected to correlate with a cessation of warming driven by the increase in sun-spot activity prior to this.”
“I wonder if the theory voiced by some -- that we just reached the end of an 11 year sun-spot cycle -- has some virtue to it.”
“This is one of those over-the-top, fantastical stories that the Sheeple in Fly Over country would perhaps hear when a sun-spot changes their radio channel to a Blue State radio channel, they hear the real story and go….”
“Some good pictures of the solar corona taken during solar eclipses, a series or two of sun-spot photographs, and a very limited number of successful attempts made upon the moon, and planets, and star clusters, were all the fruits of their labors.”
“Like magic that sun-spot always quickened their pace, and they often hailed it with a shout.”
“When a sun-spot has completed its period of existence, the photospheric matter overwhelms the penumbra, and rushes into the umbra, which it obliterates, causing the spot to disappear.”
“The exact moment of the origin of a sun-spot cannot be ascertained, because it arises from an imperceptible point; it grows very rapidly, and often attains its full size in a day.”
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