Page:The Friendly Stars by Martha Evans Martin.djvu/145

 The difference of opinion among astronomers as to the limitation of the stars is based in part upon their ideas of the destructibility of light. It is certain that we do not get an infinite amount of starlight. If we did, all space, they say, would be filled with a diffused glow and there would be no such thing as darkness. For it is not necessary that we should actually see the stars in order to have light from them. Those that we can see with the naked eye give only about ninety per cent, of the total starlight received by us. The naked-eye and the telescopic stars combined give only about one one-hundred-and-eightieth as much light as the full moon. But on a bright star-light night the light we receive is equal to about one-sixtieth of full moonlight, which shows that we get three times as much light from the stars whose rays are too faint to be seen as from all the other stars together.

It has been shown by photography that we get light from stars that even the largest telescope has not discovered. The photographic plate is so sensitive that, if it is exposed to their rays long enough, it will record the existence of the faint and far-off