When light travels from the earth to space, how does it transform from waves to photons? In fact, why does it ever bother being generated in waves at all? Or is it only a photon in a vacuum?Thank you for your illumination.
ANSWER PERSON RESPONDS: AP knows what needs to be known about light. You need good light to read a book, and also to keep from tripping down the stairs. I don’t quite have the room here to write the volumes of information that exist on the physics of light.
The way to figure it out is to ask yourself, if you were light, would you rather be a wave or a particle? Wouldn’t you really rather have characteristics of both? Any self-respecting light beam would.
When it comes to the physics, despite being much maligned by many academics these days, you might want to start with some of the Wikipedia articles, such as the article on Wave-particle duality, which has some nice links to discussions of this topic. Keep in mind that there is a difference between electromagnetic waves, like light, and mechanical waves, like a tsunami — light waves can exist in a vacuum.