Solar radiation

“ We have to ask ourselves: Will not the store of energy in the sun, which goes out, not only to the planets, but to a far greater extent into unknown domains of cold space, come to an end, and will not that be the end of all the joys and sorrows of earthly existence? The position appears desperate when we consider that only one part in 2300 millions of the solar radiation benefits the earth, and perhaps ten times as much the whole system, with all its moons. The solar radiation is so powerful that every gramme of the mass of the sun loses two calories in the course of a year. ”

“ There is absolutely no philosophical basis for distinction between the visible and invisible radiations of the sun, except in the one point of vibration-frequency—their pitch, to use the analogy of sound. The expressions thermal, luminous, and chemical rays are apt to be misleading. All the waves of solar radiation are carriers of energy, and when intercepted do work, producing heat, or vision, or chemical action, according to circumstances. ”

“ It will thus be seen that the indications are preserved from errors arising from atmospheric currents, and from the absorption of heat by aqueous or other vapours, the whole of the solar heat passing through the vacuum direct to the blackened bulb. The contained mercury expanding, carries the recording index to the highest point, and thus is obtained a registration of the maximum amount of solar radiation during the twenty-four hours. ”

“ It is certain that the sun must under such circumstances fall some degrees in temperature each year. In a couple of thousand years the change in temperature would be sufficiently great to affect in the profoundest manner the supply of sunbeams. As, however, we know that for a couple of thousand years, or, indeed, for periods much longer still, there has been no perceptible decrease in the volume of solar radiations, we conclude that the great luminary cannot be regarded merely as a glowing solid globe dispensing its heat by radiation. ”

“ The mean value which has been arrived at is fourteen, and the fundamental fact with regard to the solar radiation which we are thus enabled to state is that an area of a square foot exposed at right angles to the solar rays, at a distance of 93 millions of miles, will in each minute receive from the sun as much heat as would raise one pound of water fourteen degrees Fahrenheit. ”

“ Solar Radiation Thermometer.—“As the interchange of heat between two bodies by radiation depends upon the relative temperature which they respectively possess, the earth, by the rays transmitted from the sun during the day, must be continually gaining an accession of heat, which would be far from being counterbalanced by the opposite effect of its own radiation into space. ”

“ Any directed quality in radiant energy increases its effective temperature. Splitting a beam into two at s reflecting and refracting surface diminishes the temperature of each part; it is true that if the reflecting surface were non molecular the operation could be reversed, but actually the reversed rays would encounter the reflecting molecules in different collocations, and could not (§ 11) recombine into the same detailed phase-relations as before. The direct solar radiation falling on the Earth is almost completely convertible into mechanical effect on account of its very high temperature ”

“ It seems, therefore, most probable that we can not for the future reckon on more of solar radiation than, if so much as, twenty million times the amount at present radiated out in a year. It is also to be remarked that the greatly diminished radiating surface, at a much lower temperature, would give out annually much less heat than the sun in his present condition gives. ”

“ For example, if a land surface and a water surface have the same temperature and an equal amount of heat is added, the land surface becomes hotter than the water surface. Conversely, with equal heat loss, the land becomes colder than the water.
The Earth receives energy from the sun in the form of solar radiation. The Earth and its atmosphere reflect about 55 percent of the radiation and absorb the remaining 45 percent converting it to heat. The Earth, in turn, radiates energy, and this outgoing radiation is "terrestrial radiation". ”

“ The actuating force of every wind that blows; of every mighty current that streams through ocean depths; the motive cause of every particle of vapour in the air of every mist and cloud and raindrop, is Solar Radiation.
“The delicate tremor of the sun’s surface particles, shot hither through thirty million leagues of fine intangible æther, has power to raise whole oceans from their beds, and pour them down again upon the earth. We are apt to measure solar heat merely by the sensation it produces on our skin, and think it small and weak accordingly; a good coal fire will heat us more. ”

“ 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. ”

“ About 36 percent of the solar radiation received on the earth, taken as a whole, is reflected, but this percentage varies greatly with the kind of surface. Clean, fresh snow reflects about 80 percent of the sun's radiation, dry sand about 30 percent, and dark coniferous forests about 5 percent. ”

“ Although these particles are sustained by the gases of the sun, and are associated in aggregations which form the dazzling clouds of the photosphere, yet each one of them, in so far as its individual radiation is concerned, ought to be regarded as a solid body. The radiation from the sun is, therefore, essentially not the radiation from an incandescent gas; it is the radiation from a glowing solid. This is the reason why the solar spectrum is of the continuous type. ”

“ It is evident that the average heat gained from incoming solar radiation must equal heat lost through terrestrial radiation in order to keep the earth from getting progressively hotter or colder. However, this balance is world-wide; we must consider regional and local imbalances which create temperature variations.
Temperature Variations The amount of solar energy received by any region varies with time of day, with seasons, and with latitude. These differences in solar energy create temperature variations. ”

“ But as energy could not be lost, that disappearing potential energy must be manifested in some other form. This was accomplished by its transformation into heat, which kept the sun so far supplied as to maintain its radiation unabated for uncounted thousands of years. It was easily demonstrated that a shrinkage in the solar diameter too small to be appreciable by any measurements we could make, would, nevertheless, set free a quantity of heat sufficient to maintain the radiation for a period of two thousand years. ”

“ This allows us to take the latitudinal variation of incoming solar energy into account, for example: in general, areas near the equator receive more energy, and the incoming energy drops off as we move north or south toward the poles. Alternatively, if we are interested in differences in radiation received by different levels of the atmosphere, we might implement a one-dimensional model that’s organized vertically, rather than horizontally. ”

“ It may be some other form of solar radiation to which we are not accustomed on the earth, but which is specially effective here when the sun is uncovered because of the greater nearness of Venus. This atmosphere, notwithstanding its density, may well be diaphanous to the ultraviolet rays, owing to some peculiarity in its composition which I have not had time to study. At any rate, it is evident, from what we have seen, that the rays of the unclouded sun almost instantly affect the brain. ”

“ If, then, we depend upon solar radiation for our very existence from day to day, it can not be said that we are only remotely interested in solar physics, and the question whether and how solar energy, comprising the rays of heat, of light, and the actinic rays, is likely to be maintained, is one in which we have at least as great a reversionary interest as we have in landed estate or other property. ”

“ The material we used should not be darkened or discolored by prolonged exposure to ultraviolet radiation, and it should have good thermal conductance, so that some of the heat absorbed by the solar cells could be conducted out to the cover plates and re-radiated. ”

“ Unless there exists in nature some process, of which we know nothing at present, whereby energy is renewed, our solar system must one day sink to this absolute zero of temperature. The sun, the earth, and every other body in the universe is steadily radiating heat, and this radiation cannot go on for ever, because heat continually tends to diffuse and to equalise temperatures. ”

“ Atmospheric transmittance, solar constant, solar flare activity, solar particle detection, Earth radiation budget wave receiver technology is rapidly advancing to submillimeter wavelengths which will enable the measurement of many additional minor atmospheric constituents that play a part in radiative transfer processes. ”

“ Finding out how radiation would affect various kinds of solar cells; Making experimental cells and, when the best had been picked, determining the best ways to make them in the large quantities we would need; and Developing ways to mount the cells on the Telstar satellite so that they would withstand the stresses of being launched, the effects of radiation particles, and extreme changes in temperature. ”

“ Formulas have been derived for the energy of radiation from the upper limits of the atmosphere, for the changes in the radiating power, and for the frequency of eruptions and spots. The results thus obtained appear to be in close agreement with observation. The object of the article is to give an abstract of the main principles upon which is built a new solar theory. In a paper which is to appear in the Annals of the Edinburgh Royal Observatory the author will enter more in detail into the various applications of the theory to periodic phenomena at the sun's surface. ”

“ Devices on another facet measure the radiation damage to solar cells protected by various thicknesses of sapphire. For the second radiation experiment—particle counting—four different types of silicon diodes are used as particle detectors. These measure the energy deposited both by protons of three energy levels and by electrons as the satellite passes through belts of natural and man-produced radiation in space. ”

“ He not only produced combustion, fusion, and incandescence by invisible radiation, but he proved that in the case of the electric light the invisible rays are no less than eight times as powerful as the visible radiations. He obtained all the colours of the solar spectrum from a platinum foil raised to incandescence at the invisible focus; and this rendering of a refractory body incandescent by invisible rays he called calorescence. ”

“ Wright also took moving pictures of Sri Yukteswar during his last Winter Solstice Festival in Serampore.
46-7: “What we eat is radiation; our food is so much quanta of energy,” Dr. George W. Crile of Cleveland told a gathering of medical men on May 17, 1933 in Memphis. “This all-important radiation, which releases electrical currents for the body’s electrical circuit, the nervous system, is given to food by the sun’s rays. Atoms, Dr. Crile says, are solar systems. Atoms are the vehicles that are filled with solar radiance as so many coiled springs. ”

“ In the very act of parting with heat, the sun develops a fresh stock. His radiations, in short, are the direct result of shrinkage through cooling. A diminution of the solar diameter by 380 feet yearly would just suffice to cover the present rate of emission, and would for ages remain imperceptible with our means of observation, since, after the lapse of 6,000 years, the lessening of angular size would scarcely amount to one second. ”