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Weed_O_Whirler t1_je5m1in wrote

Reply to comment by Omepas in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator

> can the crossing point exceed the speed of light?

Sure.

> does this mean you can essentially send information faster then the speed of light?

No. While there's no limit to how fast that "point" can move (since that "point" isn't a physical thing, just a concept), there's still a lag between you moving your levers, and the point of crossing moving.

A similar example, that is perhaps easier to understand- if you shine a really bright laser pointer at the moon, and then flick your wrist, you can make the "dot" of the laser pointer move across the surface of the moon as quickly as you want. That dot could move way faster than 'c'. But it doesn't break anything- because there's still the lag you'd expect from the time you pushed the button on the laser pointer, until the dot hit the moon to begin with.

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Omepas t1_je5t7bf wrote

Awesome, still hard to grasp but its been on my mind for like 30 years. the lag thing is still confusing, esp since it doenst mean you will have to send info back, but only forward to someone else. I'll ponder it and try to grasp it.

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Weed_O_Whirler t1_je66wq9 wrote

It helps to think of how you'd actually send information via crossing two long sticks. Any method you actually come up with, will end up taking longer than just shining a light at someone.

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