Why does the bicycle taillight glow?

Because the bicycle's taillight uses the principle of light reflection to emit red light. At night, when street lights, searchlights, neon lights...and the lights of various vehicles shine on the bicycle taillights, reflection occurs, so we see the light and think that the light is emitted from the taillight. And because the color of the taillight itself is red, the colored opaque body reflects the same light as it, so no matter how many colors of light from outside hit the taillight, it only reflects red light, and the light we see is red. NS.