Here's how it works:

1. Light Emission: Luminous objects, like the sun, light bulbs, and fireflies, produce their own light through various physical processes. For example, the sun generates light through nuclear fusion, while a light bulb produces light by heating a filament until it glows.

2. Light Propagation: This emitted light travels in straight lines, called rays, until it reaches your eyes.

3. Eye Structure: Your eyes have a lens that focuses the light rays onto the retina, a layer of light-sensitive cells at the back of your eye.

4. Signal Transmission: The retina converts the light energy into electrical signals, which are then transmitted to your brain via the optic nerve.

5. Brain Interpretation: Your brain interprets these electrical signals and creates the image you perceive.

In essence, you see luminous objects because their light travels to your eyes, triggers a reaction in your retina, and ultimately creates a visual image in your brain.