Comment on wat
skisnow@lemmy.ca 2 days agoThe end of the stick would respond at the speed of sound travelling through the medium of a stick.
but how will it look like?
for a short scale it’ll be a straight line. but a few light years away? where the abstract dot is moving faster than the speed of light? what shape would you see? definitely not a straight line. and definitely some time issues. like it’ll hit you and then you’ll see it hit other planets you’re left and right?
Think of it like a hosepipe. You’re on the lawn with s long stream of water coming out of the hose. If you flick it quickly it doesn’t stay in a straight line. The beam of water curves as you move.
Because the beam of water isn’t an object. It’s a stream of particles which are constantly being emitted from the tip of the hose
Same thing with a laser beam. It’s a stream of photons being emitted from the laser. If you flick the laser, the photons which have already been emitted will continue in a straight line. Any which are emitted during the flick will head off in a straight line in the direction the laser was pointed. End result:a curved beam
that makes sense, but I’m trying to imagine how that beam would look like a few light years away before it hits you, when it hits you, and after.
Same as the beam of water, but on a much bigger scale and with the curve being much smaller because the things being emitted are so much faster
Korhaka@sopuli.xyz 2 days ago
Now I wish I had a nice big wall about a light second away and a massive laser to draw things on it.
Bonus: angle the wall so that the left side is a light second and the right side is a light minute away. Alternate the laser on/off.
starman2112@sh.itjust.works 2 days ago
Good news! We do have a nice big wall about a light second away! Hard to find a laser that’ll make a visible dot on the moon, though
NannerBanner@literature.cafe 1 day ago
what-if.xkcd.com/13/
Lovely how xkcd seems to have the answers to life and its mysteries.