Authentic Science Fiction Monthly No. 71 — page 124: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

ate hy? ) = AUTHENTIC SCIENCE FICTION a Ra s i not because of anything in- herent in space itself. Any gas, when released from com- pression, will show a marked drop in temperature, and the greater the expansion the greater the drop. This is understandable when we stop to think about it. Take a room, or the cabin of a spaceship, with a capacity of a thousand cubic feet and a temperature of fifty degrees Fahrenheit. Compress it into one tenth of its previous volume. We now have a tank of gas of one hundred cubic feet—but we still have all the heat of the original quantity. In other words, we have one hundred cubic feet of gas at a temperature of 500 degrees Fahrenheit—this, incidentally, is the principle of the diesel engine. Now do the reverse. Let the air in the cabin expand to infinity. Naturally, the tem- perature drops with a con- sequent freezing of any mois- ture content. The same prin- ciple is used in all refrigera- tion devices. 123 Here on Earth heating and cooling are complicated be- cause we have to deal with three variables instead of one. In space the reverse is the case. On Earth there are three ways by which an object can lose heat: by conduction, by con- vection and by radiation. Heat a bar of metal until it glows; that is radiation. Wave it about and let the air cool it; that is convection. Dip. it into a bucket of water; that is conduction. And an object can gain heat in the same way. . : In space it is different. Unless material is actually thrown away so that the heat goes with it, as in the in- credibly hot exhaust gases, for example, the only way to lose heat is through the radiation of electromagnetic waves; infra-red in the case of cool bodies, and visible light as well in the case of extremely hot ones, such as the glowing bar of metal. | Heat can also reach a body by radiation from the sun or the stars. It can also COMME OOXSsCohin