Trick Question.

[RWNJ]

OK. You have two photons traveling towards each other. They are both, of course, traveling at the speed of light. What is their combined velocity at the point of impact?

 

[Jimmy_Chitwood]

OK. You have two photons traveling towards each other. They are both, of course, traveling at the speed of light. What is their combined velocity at the point of impact?

zero

 

[mamooth]

It's complicated.

From the POV of an outside observer, they'd see the distance between photons closing at 2C.

From the POV of a photon, they'd see the other photon approaching at 1C.

However, a photon can't really have a POV, as being it's moving at the speed of light, a photon doesn't experience time as we know it.

Also, photons can't "impact" each other. They will pass through each other. Photons can only interact with things that have mass.

 

[SixFoot]

e+/e-

 

[RWNJ]

It's complicated.

From the POV of an outside observer, they'd see the distance between photons closing at 2C.

From the POV of a photon, they'd see the other photon approaching at 1C.

However, a photon can't really have a POV, as being it's moving at the speed of light, a photon doesn't experience time as we know it.

Also, photons can't "impact" each other. They will pass through each other. Photons can only interact with things that have mass.

The speed of light is always measured from the point of the observer. For instance, if you are driving a car at the speed of light, then turn on your headlights, what happens? The light will travel away from you at the speed of light. That doesn't mean it's traveling twice the speed of light. An outside observer would still measure it as the speed of light. It doesn't make sense, but that's what the egg heads tell me.

 

[Vikrant]

OK. You have two photons traveling towards each other. They are both, of course, traveling at the speed of light. What is their combined velocity at the point of impact?

Speed of light is constant in vacuum regardless of the speed of the observer. How is that possible? It is possible because light alters the space it travels through. This neutralizes the relative speed of the observer. However, when light enters a medium, its speed starts to retard and it may undergo one of the followings depending on the medium: absorption, transmission and reflection. It will certainly undergo refraction at the point where density of the medium changes.

Coming back to the original question, when two photons approach each other traveling at the speed of light, what will be their combined speed? This is a misleading question in my humble opinion. Of course, mathematically speaking when you combine 1C + 1C, you get 2C. However, it has nothing to do with the state of the respective photons as one photon cannot collide with another photon. Why is that? It is because photons are bosons. And two bosons, unlike fermions, can occupy the same space - therefore, we have no collision. In other words, bosons do not obey Pauli's Exclusion Principle. Now, why is that? That is because the particles that are classified as bosons have integer spins as opposed to fermions that have half integer spins. This slight distinction is responsible for mysterious behavior of bosons. It was first discovered by an Indian physicist by the name of Satyendra Nath Bose. He was so confounded by these mysterious particles that could be present in two places at once that he called them God particles. Later on French physicist Paul Dirac gave them a name boson to honor Satyendra Nath Bose.

That in a nutshell should answer your question.

 

[BlackFlag]

OK. You have two photons traveling towards each other. They are both, of course, traveling at the speed of light. What is their combined velocity at the point of impact?

^ reported to the CIA

 

[Vikrant]

OK. You have two photons traveling towards each other. They are both, of course, traveling at the speed of light. What is their combined velocity at the point of impact?

^ reported to the CIA

It is a fair question. The important thing to know is that photons are bosons and that is why they do not collide.