Does light get fainter as it travels?

    We know that the farther off a bright thing is, the less bright it seems. The Moon, or a planet like Venus, is brighter than the stars to our eyes, though not a ten thousandth part so bright in reality,    because it is near. tight will travel on fOfever unless it is stopped. Still, somehow, light gets fainter as it travels.

The reason is that the light spreads in all directions as it travels, and so gets less intense at any particular place. If you have ever played with a magic lantern, you know what a bright spot of  light it throws when it is placed near the screen, but when it is moved farther away the light gets fainter as it gets wider. The law governing this is known precisely. If the distance is doubled, the light is one-fourth as bright; if the distance is triple, one-ninths bright; if quadrupled, one-sixteenth as bright. To get the intensity,  you must take the square of the distance- i.e., multiply it by itself, and then the intensity is so much less. We say that it varies inversely as the square of the distance. if it varied directly, then the light would be sixteen times as bright, when the distance was four times as great, instead of being one-sixteenth as bright. This 'law of inverse squares' is true for the intensity of light, sound, magnetism, heat, and gravitation.