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If we had the ability to make an actuator that could turn around at or past the speed of light and I attached a high miliwatt laser to it, then spun the laser around on the actuator at the speed of light, would the light beam bend act like a the stream of water from a spinning hose as the laser went around it?

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    $\begingroup$ The stream of water doesn't bend either: each bit goes straight, but each bit is going straight in a different direction. $\endgroup$ – dmckee --- ex-moderator kitten May 30 '13 at 0:19
  • $\begingroup$ This is probably not what you had in mind, but it is possible to bend light by gravitational lensing. Now, I'm obviously being facetious in using the active voice since we can't control anything that has enough mass to bend light at any useful scale. $\endgroup$ – Zen May 30 '13 at 1:08
  • $\begingroup$ This thought experiment presupposes you can move something faster than the speed of light, which means no logically consistent conclusions can be drawn here. $\endgroup$ – user10851 May 30 '13 at 1:38
  • $\begingroup$ If we where to approach this from a theoretical point (we could get something to move at or faster then the speed of light) of view then what would be the answer, would you get a curved beam of light as the light beam went through the air? $\endgroup$ – Sheathey May 30 '13 at 2:06
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    $\begingroup$ dmckee's comment says it all. Your spinning hose is shooting pieces of water, each of which travels in a straight line. Your spinning laser is doing the same thing with pieces of light. The curvature of the stream is only a perception. The particles are each moving in a straight line, not in a curve. $\endgroup$ – Mike Dunlavey May 30 '13 at 2:15
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Yes the light beam behaves exactly like the water. In both cases particles are emitted in a specific direction and travel in a straight line

You would have to spin the source quite quickly to have an noticable 'curvature' of the light, or be viewing it over a very large scale.

You also need somethign to scatter the light, you can't see a light beam heading away from you. What slightly complicates the picture for the light is that you also have to take into account the time taken for the light to reflect off the medium and reach your eye - so you would only see the correct pattern if you were directly overhead.

There is a similar effect to this seen in reality where jets of light from a spinning star illuminate the surrounding gas

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