Rensselaer Journal, Volume 11, Number 2, Rensselaer, Jasper County, 20 June 1901 — THE SUN’S HEAT. [ARTICLE]

THE SUN’S HEAT.

Why It Seems Greater on the Barth Ths* ' Out in Space. A correspondent asks: “Docs the heat of the sun come to the earth the same as it would from a Are from which we stood only a short distance away? And, if so, why is it so cold between us and the sun?” These questions have doubtless puzzled a good many people. It Is suspected that the temperature of interstellar space, outside the earth's atmospheric envelope. Is several hundred degrees colder by the Fahrenheit scale than the lowermost stratum of air in the sunshine of a summer day. Yet When one stands-before a stove he notices that the heat diminishes'' steadily with distance. The two phenomena do not appear to be alike at Arst sight Nevertheless, a comparatively simple explanation for the difference is given. The wisest students of the sun have yet a great deal to learn concerning it, and it is possible that existing theories on the subject may be upset in the futiire. But at the present time It is believed that light, heat and electricity are all vibrations of the other. Light has the shortest waves, and these in turn are of unequal length, the violet and blue waves of the spectrum being shorter than the orange and red. The waves that produce the sensation of heat when they reach us are still longer, while these in turn are exceeded by those which give rise to electrical phenomena. Heat and electricity, though, differ somewhat from light rays in their behavior. The energy which comes to us from the sun or a lamp in the form of light cannot be stored up on arrival; that is, not as light. It is thought that when light waves hit us they aro converted into heat, but the quantity is so small we are not sensible of it. Now, it seems probable that under certain circumstances, nnd up to a certain limit, electricity can accumulate in the air. But however that may be, bent certainly does, and the moisture in the earth’s atmosphere is largely responsible for catching it and retaining It There are other materials (of which glass is one) that will let heat go through in one direction and not In the other. Thus it is possible to develop greater warmth In a greenhouse than outdoors,, even when no artificial means of developing heat Is employed. The heat comes through the glass and is there imprisoned. The molsturo of the atmosphere behaves in the same manner. Theoretically at least it should be possible to Imitate this phenomenon with a stove in a large room. All Interchange of air with adjacent regions should be absolutely checked for a sufficient time to prevent changes of temperature from this cause, and some way should be found to keep the heat radiation from the stove uniform during the experiment. Then a glass fronted and perfectly tight case, placed a suitable distance away, ought to store up heat in such a manner that after a time a delicate thermometer Inside would read a little higher than one outside and close to the glass. But it Is doubtful whether the experiment could be conducted in any ordinary household in such a manner as to yield results of any sclcntlAc value. It would be better to undertake it in a specially arranged laboratory.