Authentic Science Fiction Monthly No. 52 — page 94: what you’re looking at

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

AUTHENTIC SCIENCE FICTION further light, too, on any of the questions already dis- cussed. It will be team work that gets us into space—the total results of all our thoughts about what will be possible and what may not be possible, especially what may not. BLACK SKIES New knowledge comes from experience. Remember the cover of Authentic No. 49, out last September? A black sky on a planetary surface where no air or other atmos- phere was found? Will it really be like that when we get there? In each of my articles I have tried to describe some little experiment that you can do with quite or- dinary terrestrial objects. From the experience thus obtained we have made cer- tain deductions and applied them to space. This little experiment that I am going to describe now will show those not already familiar with the invisibility of light how it is we can be pretty certain that black will be the colour of the sky on an airless planet—or rather why such a place will have no sky. First obtain a flat-sided glass vessel. A good medicine bottle will do, although a 93 square vessel with its sides more truly flat will do better. Put a small quantity of glycerine or other oily colour- less substance into the bottle, cork up and shake vigorously for several minutes. Allow to stand. You now have a space enclosed in the bottle con- taining air which is virtually dust-free. Next, it is necessary to establish a beam of light all of which is travelling in one direction. This can be done conveniently by enclosing an ordinary electric hand torch— or a flex-fed light bulb—in a box with a small hole or slit in one side of it. If, now, a small cardboard screen, also perforated or slit, be placed six inches or so in front of the hole in the box, any light get- ting through both apertures must be travelling along the straight line joining them. Thus a beam of unidirectional light will be obtained. Now, in a darkened room, direct this light so that it falls perpendicularly on one of the flat faces of the prepared vessel. The path of the light in the air before it reaches the glass will be clearly visible, and the light after it has left the vessel and is passing beyond it will be visible, but comiclbooks.corn