What Is a Luminous Object?
A luminous object is any object that produces and emits its own light. Unlike non-luminous objects, which are only visible because they reflect light from another source, luminous objects are their own independent sources of light.
Section 2: Natural vs. Artificial Luminous Objects
Luminous objects are categorized as either natural or artificial. Natural luminous objects include the Sun, stars, and fireflies, which generate light through processes like nuclear fusion or bioluminescence. Artificial luminous objects are human-made and include items like light bulbs, candles, and television screens, which produce light via electricity or chemical reactions.
Section 3: A Practical Example: The Sun and the Moon
A classic example to illustrate this concept is the Sun and the Moon. The Sun is a luminous object because it generates its own light through nuclear fusion. In contrast, the Moon is a non-luminous object. It does not produce any light; we can only see it because its surface reflects the light from the Sun.
Section 4: Importance in Optics
Understanding the difference between luminous and non-luminous objects is a fundamental concept in optics and astronomy. It explains the basis of vision—that we see either by observing light sources directly or by observing the light they reflect off other objects. This principle is key to understanding shadows, color, and how light interacts with matter.