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Is the “How to break the speed of light” minute physics video wrong?

Radius of the moon - 1737 km. Thus circumference of the side that can been seen from earth - pi * 1737 = 5457 km.

Speed of light - 300 kmps

So if I point a lazer at one edge of the moon from earth and then move it to the other side in one second I will ultimately make the lazer spot travel 5457km in 1 sec. Thus the speed of the light spot is 5457 kmps!

What is it that I am missing interms of concepts here? When we say nothing can go beyond the speed of light then what does "nothing" mean?

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marked as duplicate by David Z Jan 24 '13 at 6:57

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1 Answer 1

You're imagining light as a solid, rigid body that can instantly get from point to point. You're still thinking in terms of small distances.

In fact, what will happen is that when you move the laser, the light will "wave" as if it was on a string, and then end up at the other side of the moon. There is no contradiction there. The photon doesn't care about its source - once it has left the source, even if you move the source it will not react.

So a photon halfway through the moon will not move with the laser pointer when you wave the laser pointer around.

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