Hypothetically, could something travel faster than the speed of light if it's traveling in a different medium?
My Optics lecturer said something about how since light travels in a vacuum, you could, potentially, have something travel faster in a different medium, one other than a vacuum.
True or false?
It has been done. Get something traveling in a vacuum just below the speed of light, and then whack it into a medium where it is now traveling at faster thant he speed of light in that medium. The particles that have had this done to them, slow down dramatically, and radiate their previous energy – its called Cerenkov radiation. So , yes – particles can exceed the speed of light, if they are in some medium other than a vacuum, but not for very long.