Can Light Accelerate When Changing Direction?

[Lunct]

I know that light is always at constant speed but does it ever accelerate when changing direction, if you put light through lots of different densities it curves into the Brachistochrone curve, would that be an instance of light acceleration.

 

[mfb]

I know that light is always at constant speed

In vacuum.

but does it ever accelerate when changing direction, if you put light through lots of different densities it curves into the Brachistochrone curve, would that be an instance of light acceleration.

I guess you can call that acceleration, yes.

You can get a speed that changes continuously if you send it through a variable medium, e.g. through the atmosphere vertically (as the speed of light at sea level pressure is lower than the speed of light higher up).

 

[Dale]

I know that light is always at constant speed but does it ever accelerate when changing direction, if you put light through lots of different densities it curves into the Brachistochrone curve, would that be an instance of light acceleration.

In a rotating reference frame light does accelerate in a vacuum

 

[Orodruin]

In a rotating reference frame light does accelerate in a vacuum

Coordinate acceleration ... You might as well say it does not have constant speed.

 

[Dale]

Coordinate acceleration ... You might as well say it does not have constant speed.

Yes

 

[CWatters]

I know that light is always at constant speed but does it ever accelerate when changing direction, if you put light through lots of different densities it curves into the Brachistochrone curve, would that be an instance of light acceleration.

I recall someone posted a homework question that went something like...

A beam of light is bent by a prism mounted on sensitive weighing scales. Calculate the apparent change in weight when the light is turned on/off.

 

[sophiecentaur]

That's certainly a valid thought experiment. Momentum will be conserved.

 

[mfb]

With angular momentum, it is a real experiment (with a different focus, however).

The force from deflection in a prism should be measurable as well, but I'm not aware of specific experiments.