What happens to a spark of light trapped inside of a sphere with a mirror surface on the inside?

Answer 1

Theoretically, it'd be trapped inside the sphere forever. In practice, mirrors are not perfect. The material the light bounce off would absorb energy, allow light to "leak" through, etc etc.


something related.. maybe...
This remind me of one thought experiment to determine the position and energy of an electron simultaneously by putting the electron in a box and making the box smaller and smaller. Heisenberg's uncertainty principle said u cannot determine both the momentum and position of the electron infinitely accurately at the same time. The idea is to make the box so small eventually the electron would be confined to a fixed position with 0 velocity and known position. But however, by making the box smaller and smaller, the wall of the box push against the electron, giving it more and more energy and when u thought u have zoom in on its position, the electron would have so much energy it'd simply burst out of the box.

Answer 2

In practice, the mirror would not be 100% reflective, meaning that with every bounce, it would absorb some light/energy and, as ILOVESCIENCE pointed out, the light would "wear out". Even the air inside would do that eventually.


If, however, you had a perfect mirror and perfect vacuum AND could observe without interfering (you can't, if you or an instrument would be inside to see or measure, you/it would absorb the light) then, I GUESS there would be almost perfect "darkness". the waves bouncing erratically in all directions would partially cancel each other out. If the sphere were punctured or broken, the light would flash.

Answer 3

Making a light trap out of mirrors is very, very difficult, and nobody has yet succeeded. The reason is that the most reflective mirrors ever made are only about 99.999% reflective, and every time the light is reflected its intensity is multiplied by a factor of 0.99999. Say your two mirrors are 1 metre apart in a vacuum chamber, so no light is absorbed by the transmission medium. The speed of light is 300 million metres a second, so after 1 second the light has been reflected 300 million times as it bounces between the two mirrors. 0.99999^300 million is very close to zero; my calculator says it's zero. In other words, with the best equipment we can make, the light will be absorbed and converted to heat very quickly.

Answer 4

How is that possible. There would have to be a source to the light in order for the light to be able to do anything at all. And since you can't see it, it would have to be a faith thing. Like the tree falling in the forest. Personally, I think it would bounce around for all the duration of the sphere's life, bouncing around at precise and random angles.When the sphere deteriorated enough, the light would burst free and race to the heavens to be with his brothers and sisters again. But then again, I do have an over active, optimistic imagination.

Answer 5

Having a light source in the perfectly reflective sphere would ruin the perfect sphere. Having a way to measure the light would ruin the perfect reflectivity

Answer 6

As no surface is a perfect reflector and the air inside the sphere also has slight absorption/scattering properties, it would eventually be absorbed by the molecules of the sphere and/or air - thereby exciting the molecules which eventually becomes thermal (heat) energy.

Answer 7

The light would basically bounce around inside until the energy runs out.

Answer 8

the light would not keep reflecting forever, because the energy would eventually kind of "wear out". energy cannot last forever. unless the light was a continuous light, but then that would just be generating more light, not helping to keep it enegetic.