Where do light particles “go?”


Where do light particles go? If a person is in a dark room, and they open a curtain, light illuminates the room from outside. But then, when the curtain is closed, the room is dark again, and the light is no longer there. Where did it go?

I probably have a flawed understanding of how light particles work.

In: 10

When a photon runs into an object, it interacts with the atoms on its outside and is absorbed or reflected. You can see the reflected photons, if they go into your eye. The absorbed ones are gone, heating the object.

Since no material is perfectly reflective, some of the light bouncing around a room is absorbed every time it hits an object. Bright white paint only reflects ~90% of the light that falls on it, absorbing the other ~10%. After just 100 bounces off of white paint, only 0.003% of the original light will remain—and light moves so fast that it can travel across an ordinary room millions of times per second.

The issue is that “particles” is an incomplete description of light. Light photons are waves (ripples of electric and magnetic field) just as much as they are particles.

So your question is kind of like asking “where do waves go when they hit the shore?” Their energy just dissipates.

In the case of light, within a few bounces the photons get absorbed and are turned into heat.

It stopped existing. When light hits an object, some of it is reflected, and some of it is absorbed. That absorbed light stops existing and turns into heat.

Light acts like a particle (and a wave) but light doesn’t actually exist. Photons are what is known as a virtual particle, and is used to model the behavior of the transmission of the “information” in electromagnetic interactions. light particles don’t go anywhere when the light is turned off because they were never there in the first place