The question depicts whether one bit of light can bounce off another bit off light like the way when two objects get collided and bounce off each other. Well, the answer is a big no. Light is made up of small quantum packets known as photons. Photons are part of a quantum particle group called Bosons.
Upper image is from shutterstock
One speciality about the bosons is that they can occupy the exact same quantum state at the same time. This causes the creation of laser beams as laser beam is a collection of many photons all in the same quantum state. This phenomenon occurs in case of Bosons. But non-bosons or fermions can’t be in the same state. This is called Pauli’s Exclusion Principle.
The interaction of light occurs with objects that possess some electric charge. But a photon doesn’t have any electric charge because photons are bosons, and bosons were named for having no electric charge, hence they don’t interact with each other. Hence, they don’t bounce off each other.
From another point of view, if we actually observe the process, we can also understand why they don’t bounce off each other. When two photons collide, first photon degenerates into one positron and an electron. This process is called pair production.
Can Light particles can Really pass through each other
The same happens in the case of the other photon too. So, when they collide, positron of first photon interacts with electron of the second photon and again converting to a photon. This process is called annihilation in which two opposite charged particles interact with each other to give rise to another particle. Here that particle is photon. So, in the end, it all appears as if nothing has happened; as if two photons haven’t interacted with each other. Hence, the two light rays just pass off each other without bouncing off.
Author: Som Abhisek.
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