8 ms·
The simplest example of something that "can travel faster than light" without transmitting information faster than light is rapidly moving the little dot a lase
by kfitughf7 5y ago
The simplest example of something that "can travel faster than light" without transmitting information faster than light is rapidly moving the little dot a laser pointer makes. The dot itself can apparently travel across a surface faster than lightspeed (300,000 km/s), but the dot can't cause faster than light information transfer between the targets it flicks between. You could have the dot rapidly blinking a Morse code message, for example, then shine the dot at Alice and then flick the dot over to Bob, and this would let you send a message to both Alice and Bob, but not send a message from Alice to Bob faster than light.
- jafarlihi 5y agoThe dot is not moving though. By the time you have it in another surface FTL it is a totally different dot.
- test6554 5y agoThe hypotenuse of a triangle is shorter than the sum of the sides, so Bob could always send a message directly to Alice faster than Bob could send a message to you and have you propagate that message to Alice.
- dr_dshiv 5y agoThanks! That was the simple example I was looking for. I was thinking about Moire patterns and other wave patterns where the pattern can move faster than the constituent.