this has bothered me forever. even college physics professors won’t bother to talk to me about this. what would be the propertys of a very very long, very very rigid rod? (this is where everyone starts typing sacastic dirty jokes and ignores my question)
honestly it could be a short rod like a pen, but its not really interesting to think about it like that.
say I made a rod roughly a billion miles long out of something really rigid so bending and such wouldn’t be a problem (this is a thought experiment, don’t lecture me on how hard to make that would be or how nothing is ridged enough… did you people yell at einstein when he made HIS thought experiments? this is hypothetical… don’t wonder where I got a billion miles of magic adamantium)
this is a question about the rule that no information can travel faster than the speed of light. imagin I was in a space ship on one side of the rod and my freind was at the other end.
I push on the end of the rod. in my pea brain when I move something… all of it moves at once. if I push on the end of my pencil on a desk… I do not have to wait for the other end to move too.
my next thought is “oh… movement must move quickly down the length of something, that makes sense”
but if thats true, get into even MORE problems… say I grabbed the rod on an end and moved it ten feet… pushed it for ten feet… since the other end can’t move instantly or speed of light speedlimit would be broken, it must take some time before the other side moves, being a billion miles away… it must be a long time. so that means I made the rod shorter by ten miles… for the day or so that it takes till the other end finally moves 10 feet.
that means… that if the movement wave doesn’t go as fast as light I could continue to compress it… and outrun the movement and end up compressing a ridged rod into very small space… by just acting like I was moving it 999 million miles.
so since scale doesn’t matter… if I pushed the pen on my desk really darn fast… I could outrun the other end moveing? and compress my pen into a little dot for a microsecond or so before it caught up? or what if the end I was pushing was pushed farther than the other end… so the erraser was in front of the tip!? so THAT Can’t make sense!!
so then it seems that its just not possible to push something that long… but thats not right either… because whats the size limit on things you can move!?
for that matter what if you turned the rod, the speed would multiply over the distance and the tip would go WAY over the speed of light even if you were moveing it very slowly.
alright… someone smarter than me explain the propertys of such a fictional object. don’t try to explain why its not possible to make something like that… or how gravity or whatever would ruin it. just pretend its a magicly rigid matterial… pretend its a bar of neutronium or a force feild or magical elven adimentium… I can figure out the flaws in that myself, I can’t figure out the propertys of such an object when pushed.