(1) That the Sun is made up largely of gases, and that
(2) These gases are formed of various substances, and that
(3) The gases produce terrific heat, which means that
(4) The atoms or particles which form the gases are in violent motion or vibration.
(5) These vibrations start out waves in the ether which travel out into space at a speed of about 186,500 miles per second.
(6) On reaching the eye the waves pass through the lens and form a picture or image
(7) On the retina, or screen of the eye, which is made up of the ends of nerves, and these vibrate just as the atoms of the gases in the Sun which sent out the waves vibrated, and finally
(8) These nerve vibrations are sent over the optic nerve to the brain, where they take on the shape, size and colors of the Sun.
Reflection of Light.—The flame of a match, or a candle, an oil or a gas lamp, or Sun, comet or meteor, produces its own light, and for this reason these bodies are called self-luminous—that is, they are themselves the source of light.
All other objects which do not produce light, such as an apple, a stone, the Earth and other planets and moons are called non-luminous bodies.