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Question:
What creates visible light? In other words, what in the sun, or a light-bulb causes light to come into existence? What initiates it? And is the initiation (creation) of it the same thing that propels it? Is the answer for visible light the same for all electromagnetic radiation? Your feedback would be much appreciated.



Replies:
Jesse,

Many things can create visible light, but they are most often forms of electric charge losing energy. Light can often be described as a blend of electric and magnetic fields. The vibrational motion of electric charges can produce such a thing. In an incandescent light bulb, very hot electrons vibrate very fast. This is what "white-hot" refers to. Florescent bulbs have fast electrons crashing into the neon atoms in the bulb. This boosts electrons within the atoms to higher energy levels, faster vibrations. When they lose this extra energy, it comes out as light.

Star light comes from interacting protons rather than electrons. The fast protons join together to form hydrogen and then helium. They can later join to form heavier atoms. When they join, energy is lost as light. To pull these helium atoms apart, this energy must be put back. This is why small atoms seldom break apart into smaller atoms.

Dr. Ken Mellendorf
Physics Instructor
Illinois Central College



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