HNHacker News
TopNewBestAskShowJobs

kfitughf7

12 karma · joined June 7, 2021

submissionscomments
kfitughf7··on Laser pulse travels 300 times faster than light (2002)
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.