I Made a Real-Life Unilluminable Room

hey everyone today i'm going to be showing you the unilluminable room this is a room that if you have a point source of light no matter where you put it it can't light the entire room a while ago i made a room made completely out of mirrors from top to bottom even the door and it became apparent that when i went in the room and turned on a single point source of light no matter where i put it in the room it lit up the entire room now this didn't happen just because it was a small room but it turns out that no matter how big your room is if the walls are made out of mirrors and you turn on a single point source of light anywhere in that room it'll light up the entire room you can see if i use this ray simulator online that i can put a box around this point source of light and as soon as i enclose it then the entire room gets lit up no matter where i put the point source of light now it doesn't really matter what i shape this room like i can keep adding mirrors here and just get a longer let's make a long corridor here but as soon as i close it off with mirrors every single part of that room is illuminated even if i add in some curved mirrors or whatever i try to do if i enclose off the room and it's made out of mirrors a single point source of light will illuminate it everywhere i should interject here that the larger the room the less intense the light is that reaches every part of the room but it still reaches every part nonetheless now this became a pretty interesting topic of discussion among mathematicians it turns out that no matter what shape of room you propose if it were a mirrored surface that could mirror indefinitely if you put a point source of light in there it will always light up the room so in 1950 the mathematician ernst strauss proposed is there a room that exists such that you can't light every part of the room with a single point source of light with mirrored walls and for many years nobody could find a shape that you could make a room out of that the point source of light wouldn't illuminate the entire thing but then in 1958 the amazing physicist roger penrose proposed a solution to this problem he had actually found a room with a shape such that you could make it out of mirrors and a point source of light wouldn't illuminate everywhere in the room and he was able to prove mathematically why this specific shape works so to test that out i went ahead and built my own penrose unilluminable room to see if i put a point source of light in here it truly won't light up specific points in this room so what i did is i 3d printed the shape here and then i covered the inside with mirrors and so i'm going to stick a point source of light in here and see where it lights up in the room so in order to see how we're illuminating the room i'm just going to put this on a white paper the white paper is reflective but it's diffused so it's going to send light back up at the camera so you can see where it was illuminating different parts of the room so the first thing i'm going to try is i'm going to tuck the light in this back corner that seems like the most likely position that we're not going to get the light to spread around the room so sure enough i tuck it back there and it only keeps one side of the room lit up about half the room is completely dark now if i move it to the center of the room it's pretty close but right behind here and here the room's dark now actually to light up the biggest portion of the room if i put the light right here the only parts of the room that are dark are here and here so you can see my string here but as soon as i tuck it behind here it's no longer visible but if i tuck it up here it's visible all along here but not in these little corners here so it's true no matter where i put this light i can't light up this entire room what's amazing is this even works with water so i have a wave simulator in the back corner here you can see when i shine my light on here and the reflection the reflection is wiggling that's the wave that you're seeing but if you remember when i put the light in that back corner only this portion of the room was illuminated so that means if i move this any lower you shouldn't be able to see the light wiggle so you can see up here the light is really wiggly but down here it completely stops so it's very still down here and you're looking at this reflection right here so see how wiggly it is up here that's the wave you're seeing so it looks like the unilluminable room is truly unilluminable so in order to be unilluminable it doesn't actually have to look exactly like this so you can actually change these dimensions slightly and it will still be unilluminable it's a specific group of set of ellipses that have this general shape that will make it unilluminable and then besides this solution there's actually two other solutions that have been discovered so for example in these sets here there's two specific points that work if you place your source here or here the other point will not be lit up but only that one single point and thanks for watching another episode of the action lab i hope you enjoyed it if you did don't forget to subscribe if you haven't subscribed yet and also check out the actionlab.com where i sell two experiment boxes a vacuum chamber kit and a self-pouring fluid kit and thanks for watching and i'll see you next time

Channel: The Action Lab

Views: 689,180

Keywords: unilluminable room, The action lab, mirror room, illumination problem

Id: inMihNPjevM

Length: 5min 44sec (344 seconds)

Published: Wed May 11 2022