photon ping pong

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Offline jeffreyH

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photon ping pong
« on: 05/08/2015 01:19:14 »
If two players were a multiple of 300000000 metres apart with mirrored bats how easy would it be for them to play photon ping pong?

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Offline chiralSPO

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Re: photon ping pong
« Reply #1 on: 05/08/2015 01:36:51 »
I think that would be exceptionally difficult (or easy). Whoever "serves" will almost certainly score, as there would be no way of knowing the trajectory of the incoming photon until it has arrived and hit the "table." It doesn't matter how far away the opponent is, 3 meters or 300000000000000000000000000000000000000 meters, there will never be any information about the serve that reaches the player before the photon does.

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Offline jeffreyH

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Re: photon ping pong
« Reply #2 on: 05/08/2015 02:15:37 »
I think that would be exceptionally difficult (or easy). Whoever "serves" will almost certainly score, as there would be no way of knowing the trajectory of the incoming photon until it has arrived and hit the "table." It doesn't matter how far away the opponent is, 3 meters or 300000000000000000000000000000000000000 meters, there will never be any information about the serve that reaches the player before the photon does.

Yes exactly. It may seem like a very frivolous question but there are some fundamental issues here.

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Offline alancalverd

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Re: photon ping pong
« Reply #3 on: 05/08/2015 08:05:00 »
But if the receiver has a sufficiently large corner cube reflector, he can always return the shot.

Unlike a table tennis ball, the incoming photon has a very limited range of exit angle - it won't spin, weave, skid, climb or drop.

The server has to hit a table about 2 m wide at 150,000,000 meters distance, with his arm reach of about 2 m diameter. So we can ignore the table width as effectively a point, and the incident cone angle is 2/(60 x 150,000,000) degrees, as is the exit cone (assuming a perfectly reflecting table) so the receiver only needs to intercept photons in the same cone ange, i.e. within his arm span. No problem making a cube reflector  2m wide, but it would be a very boring game.
helping to stem the tide of ignorance

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Offline Colin2B

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Re: photon ping pong
« Reply #4 on: 05/08/2015 09:17:15 »
It is unlikely to catch on as a spectator sport unless you can make the photon tracks visible. Even with pulsed lasers that would mean a lot of dry ice!
and the misguided shall lead the gullible,
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