If submarine going at the speed of light and turned on the headlights?

Question

Submarine goes at speed c/2 in liquid
with refraction index n=2.

What heppens if headligths are turned on?

Answer 1

In an optically dense medium, you can outrun (or in this case run along with) the "light" from your headlights. The effect would be like a luminous sonic boom. As the sub passed, it would be like a shock wave of light.

Edit--yeah, Cherenkov radiation--I momentarily forgot the phenomenon had a name already

Answer 2

sure, there's a hazard of a prepare to commute on the fee of sunshine yet, that prepare has no longer yet been engineered. Hypothetically conversing, if a prepare grow to be traveling quicker than the fee of sunshine on a depressing night and the headlights have been became on, the railroad song might nonetheless be dark, in basic terms as though the lights furnishings have been off because of the fact by the time mild reaches a definite element in front of the prepare, the prepare could have already surpassed that element because of the fact it particularly is traveling quicker than mild.

Answer 3

Interesting question. For a second there it had me stumped.
Einstein would say that the light would leave the headlights at the speed of light. I suppose that there would be some relativistic effects because c/2 + c/2 would be c. But.....we all know near the speed of light relativistic effects become noticeable. If you were watching this from a boat on the surface of this liquid, I suspect that it would appear that the light from the headlight is moving at c. From the submarine it would appear that the light from the headlight was moving at c/2. All relativistic effects would still be in effect, but not very noticeable because everything's still at or below c.

Answer 4

Headlights on a submarine?

Answer 5

The effect is called Cherenkov radiation and is used to detect neutrinos, which hit electrons, and cause them to fly at more than the speed of light in water.