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If Two Spaceships Close at 1.4c...?


LightHeavyW8

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Phyti - You must have missed Janus' Animation

 

 

LHW

 

I saw his animation.

It's demonstrating that light moves independently of its source. Light does not acquire the speed of the emitter.

A good analogy is a boat moving in water, and a stone dropped from the boat into the water. The speed of the waves from the stone is determined by the properties of the water, and is independent of the boat speed. The counterparts for the water, stone, and waves are space, ship, and light.

You have simultaneous motion of light and two ships, and a space-time drawing is very helpful in sorting it all out.

From E's perspective, what distance did the light travel, and how much time did it take?

 

The answer is understanding that the 'closing speed' is not strictly a speed, but a rate of contraction or expansion of a spatial interval, which itself is NOT moving.

 

Close a pair of scissors. The point where they cross moves much faster than the tips, BUT that point is not an object, but the positional relation of one blade to the other.

Edited by phyti
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I saw his animation.It's demonstrating that light moves independently of its source. Light does not acquire the speed of the emitter. A good analogy is a boat moving in water, and a stone dropped from the boat into the water. The speed of the waves from the stone is determined by the properties of the water, and is independent of the boat speed. The counterparts for the water, stone, and waves are space, ship, and light. You have simultaneous motion of light and two ships, and a space-time drawing is very helpful in sorting it all out. From E's perspective, what distance did the light travel, and how much time did it take? The answer is understanding that the 'closing speed' is not strictly a speed, but a rate of contraction or expansion of a spatial interval, which itself is NOT moving. Close a pair of scissors. The point where they cross moves much faster than the tips, BUT that point is not an object, but the positional relation of one blade to the other.

The point I take issue with is your interpretation of "closing speed", which is bottom-line real for both collider operators and the EO. They both know when the experiment ends as well as, if not better than, any traveling "observers". Even Janus grudgingly acknowledged that my claim that EO observes information exchange between A & B at 1.7c is valid, even though light is only travelling through space at c.

 

 

LHW

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