Solar wind

“ It is now an admitted fact of science that the earth is dependent upon the sun for the chief portion of the energy by which terrestrial effects are produced. With the exception of the ebb and flow of the tides, all the forms of earthly power are recognized as having, directly or indirectly, a solar origin. Wind-power, water-power, steam-power, the activities of organic growth, all animal energy, and the great phenomena of changes in the crust of the globe, due to the circulation of waters through atmospheric agency, are caused by the forces of solar radiation. ”

“ If we, and those we have cited, are not mistaken in most of the views expressed, the natural effect of a partial interception or failure of the sun’s rays, by or from the existence of the spots, would be to decrease the exciting power of the solar rays upon terrestrial magnetism, and, as a consequence, the volume of the trades and their amount of moisture. This would increase the mean heat of the summer in the temperate zone—for the less the volume of trade, the less precipitation and variable wind, and succeeding polar waves of cooler air, and the greater mean heat. ”

“ Speaking loosely, it may be estimated that at the sea-level, in fair weather, neither excessively moist nor dry, about thirty per cent, of the solar radiation is absorbed when the sun is at the zenith, and at least seventy-five per cent, at the horizon. ”

“ By the unequal action of the solar heat are produced all winds and storms, and those disturbances in the electric equilibrium of the atmosphere which give rise to the phenomena of terrestrial magnetism. By the solar rays the waters of the sea are drawn up into the air in vapour, to descend again in rain, irrigating and fertilizing the land, and producing springs and rivers. ”

“ Nothing around us seems to stir; we are far from the roar of cities; above us the silence of the stars, beneath us a soft carpet of snow; not a sound to be heard, not a breath of wind stirring the branches.
And yet we know that all this is an illusion! Those bright points of light on the dark firmament are solar systems, whirling through space two hundred times faster than a cannon-ball, and under our feet the delicate snow-crystals are groups of atoms, which tremble with billions of vibrations every second. ”

“ Our atmosphere, charged with aqueous vapour, serves to shield us from the intense action of the solar powers. By it we are protected from the destructive influences of the sun’s light and heat; enjoy those modified conditions which are most conducive to the healthful being of organic forms; to it we owe “the blue sky bending over all,” and those beauties of morning and evening twilight of which
—— Sound and motion own the potent sway. ”

“ Winds and ocean currents, hailstorms and rain, sliding glaciers, flowing rivers, and falling cascades are the direct offspring of solar heat. All our machinery, therefore, whether driven by the windmill or the water-wheel, by horse-power or by steam—all the results of electrical and electro-magnetic changes—our telegraphs, our clocks, and our watches, all are wound up primarily by the sun. ”

“ The solar clouds are not little beads of water; they are little beads of white-hot material so dazzlingly bright as to radiate forth the characteristic brilliance and splendour of the sun. The solar clouds drift to and fro; they are occasionally the sport of terrific hurricanes; they are sometimes driven away from limited areas, and in their absence we see merely the black interior of the solar globe, which we call a sun-spot. Now comes the important question as to the material present in these clouds which confers on the sun its ability to radiate forth such abundant light and heat. ”

“ What principle of conservation of energy is it possible to apply to the vast quantities of light and heat which constantly disappear in the interstellar realms of space? How to account for this enormous emission of solar energy during the long period of time requisite for the development of the earth during its past geological ages. How to explain why the moon always presents the same face to the earth. Why, if the law of gravity prevails there, there are no visible traces of atmosphere or moisture in the moon. ”

“ It is of course the solar energy that has performed this task of lifting, and as the rain descends it becomes collected into the streams and rivers which on their way to the sea are made to turn the waterwheels. ”

“ By fixing our attention on the sun himself, the source of all energy here below, we run less risk of being led astray. For example: do we find, in known solar phenomena, any reason to believe that the Sun has other means of action besides his attraction, his heat, and his light? The answer, "Yes," is ready. The Sun possesses and exercises a plainly-marked repulsive power, of which meteorology has hitherto taken no account, although our atmosphere must experience its effects. ”

“ The solar influences, which regulate, and possibly determine, every physical force with which we are acquainted, are active in effecting an actual change of state in matter. The sunbeam of the morning falls on the solid earth, and its influence is felt to the very centre. The mountain-top catches the first ray of light, and its base, still wrapt in mists and darkness, is disturbed by the irradiating power. ”

“ From sunset to sunrise there is nothing to compensate the steady outflow of heat, and air and ground grow steadily colder, but with the sunrise there comes an influx of solar heat, feeble at first because it strikes the earth's surface very obliquely, but becoming more and more efficient as the sun rises higher in the sky. But as the air and the ground grow warm during the morning hours they part more and more readily and rapidly with their store of heat, just as a steam pipe or a cup of coffee radiates heat more rapidly when very hot. ”

“ The condensation of volume of the planets will give rise to great elevation of temperature, while their currents of electricity, poured into the sun, will, by their passage through its enormously compressed hydrogen atmosphere, produce intense heat, and this, rapidly communicated to the solar core within, will raise its temperature to that of the sun as we now see it, and permanently maintain it in that state of incandescence. ”

“ Many attempts have been made in tropical and sub-tropical climates to utilize the sun's heat directly for power, and Ericsson in Sweden, Mouchot in France, and Shuman in Egypt have built successful and efficient solar engines. ”

“ If we had no rain the earth would dry up, and the globe would appear as the side of the moon appears—a waterless desert. The invisible vapour in the atmosphere will produce cloud, but the moon can have no atmosphere in that sense. Vapour will also absorb heat, and intercept the sun’s heat rays, acting much as clouds do in preventing radiation and great changes of temperature.33
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All animals and plants depend upon moisture in the atmosphere as much as upon the varying degrees of warmth. A dry east wind effects us all prejudicially; warm, soft airs influence us again in other ways. ”

“ The next theme of study was the solar system, under the laws governing which our world exists, part of which it is, and upon the members of which, the sun and the moon, we are so dependent that without them life on our globe would be impossible. That magic power whereby the plant world grows and ripens its fruits abides in the sunlight. It is the sun’s heat which raises water from the earth in vapor, which returns to us in showers and dew. It is that same forceful heat, poured out on vast continents, that gives rise to the winds that cool our summers and speed the sails of our commerce. ”

“ I have said, you will remember, that we would confine our attention to that portion of the solar heat that falls upon the oceans, and to that fraction of it which is expended in the work of evaporating the water; in doing which alone, the sun raises during every minute an average of not less than 2,000,000,000 tons of water to a height of 31/2 miles—the mean altitude of the clouds. ”

“ Sun-spots of considerable magnitude have been observed to grow rapidly and then disappear in a very short period of time; occasionally a spot is seen to divide into two or more portions, the fragments flying asunder with a velocity of not less than 1,000 miles an hour. It is by these upheavals and convulsions of the solar atmosphere that the light and heat are maintained which illumine and vivify the worlds that gravitate round the Sun. ”

“ SOLAR ENERGY. The source of the energy which accomplishes all this necessary work is the sun. It is the radiant energy of the sun which causes the disintegration of rocks, which lifts vapor into the atmosphere to fall as rain, which gives life to plants and animals. Considering the earth in a broad way, we may view it as a globe of solid rock,—the lithosphere,—surrounded by two mobile envelopes: the envelope of air,—THE ATMOSPHERE, and the envelope of water,—THE HYDROSPHERE. Under the action of solar energy these envelopes are in constant motion. ”

“ As the moon now proceeds towards her first quarter, the terrestrial repulsion drives her atmosphere radially outward, while solar gravity and electrical attraction tend to hold it in the direction of the sun. ”

“ The sky here is so pure and clear in our summer that it would be a shame to neglect such an opportunity of making experiments on heat, and accordingly I have been occupied in the December solstice in determining the constant of solar radiation, that is to say, the absolute quantity of heat sent down to the earth’s surface from the sun at noon, or at a vertical incidence. ”

“ The consideration of the weather enables him to understand the state of the atmosphere about him, its effect on climate, the cause of storms, and the different action of solar energy on air, land, and water, which renders possible life upon the earth. ”

“ The intensity of solar radiation increases rapidly with increasing elevation,54 so that when the sky is clear surfaces exposed to the sun are heated much above the normal temperature. Owing to its slight absorptive power the free atmosphere is little affected; but the strata nearest the surface are heated by convection, while a contrary effect follows when the surface is no longer exposed to the sun, and radiates freely to the sky.
The air in mountain countries is rarely at rest. ”

“ The motion of the atmosphere is brought about by the action of heat here and there, and in a trifling way, by the heat from the interior of the earth escaping through hot springs or volcanoes, but almost altogether by the heat of the sun. If we can imagine the earth cut off from the solar radiation, the air would cease to move. We often note how the variable winds fall away in the nighttime. ”

“ Of the potency of the Sun’s rays we can form but a feeble conception, 21 for the amount received by the Earth is, it has been calculated, but one 2300-millionth of the whole. Our annual share would, it is supposed, be sufficient to melt a layer of ice spread uniformly over the Earth to a depth of 100 feet, or to heat an ocean of fresh water 60 feet deep from freezing point to boiling point. The illuminating power of the Sun has to be expressed in language of similar profundity. ”

“ We may ask what makes the air move, for it will not rush about in this way unless there be considerable force to drive it. Here again we perceive the influence of the sun. Tracts of land are warmed by the genial sunbeams. The air receives the heat from the land, and the warm air is buoyant and ascends, while cooler air continually flows in to supply its place. To do this it has, of course, to rush across the country, and thus wind is caused. All the air currents on our earth are consequently due to the sun. ”

“ It is obvious that in any one of the places mentioned and which lies outside the tropics, a living body might encounter days in which it would be heated by solar radiation to a much greater extent than in the tropics, and the only question would be whether the possibility of cooling, such as low air temperature, low humidity, winds or other means would compensate to avoid the effects of such insolation. ”

“ Still other conditions enable these suns to transform and send forth much of the energy of space which comes their way in the established space circuits, Many phases of physical energy and all forms of matter are attracted to, and subsequently distributed by, the solar dynamos. In this way the suns serve as local accelerators of energy circulation, acting as automatic power-control stations. ”

“ The heat of the sun is known to be variable, and the eleven years' period of sun-spots has recently attracted much attention as producing appreciable effects on the seasons. There may possibly be longer cycles of solar energy, or the sun may be liable, like some variable stars, to paroxysms of increased energy. ”

“ When we consider that the thickening of this solar atmosphere would bring back the age of ice, or its thinning carry our polar regions to tropical temperature, and when we remember that rhythmical action, not uniformity, seems to be the law of nature here, we can feel no certainty of the future constancy of the solar heat, nor of our protection against such changes as seem to have befallen other suns in space, and against which we are powerless to guard. ”

“ The solar heat, which grows for us the food by which we live, is no doubt in one sense the final cause of every meteorological change, bringing those years of want and years of plenty which are due to local variations of climate, that depend, through a chain of causes very remote and obscure, no doubt, yet finally, upon the sun. ”

“ If the constitution of the Sun be that which is above inferred, it does not seem difficult to conceive still more specifically the production of these appearances. Everywhere throughout the atmosphere of metallic vapours which clothes the solar surface, there must be ascending and descending currents. ”