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On a planet whose rotation was so fast the surface moved at close to the speed of light, what would the result of building a tall tower be?
Yes, this is a nutty, impossible planet, but it's my hypothetical and we're doing it anyway.
Seems to me that you could technically break the light barrier just by building a tall enough structure on a spinning object (or two, one on each side, to keep the centre of gravity in the same place), especially if it was really belting around to begin with. However, I'm also pretty sure that it'd be impossible, so what mechanism would come into play to stop you from doing this? I guess the rotation would slow down, but I'm too derpy with my physics to understand why.
So, uh, why? Or would it? I dunno. that's... why I'm asking ;)
Ah, I think I figured it out. The rotation wouldn't slow because you could never add more height. Climbing the tower counts as accelerating, and takes an increasing amount of energy the closer to the speed of light you get. So you could never push the material required up to build any higher. :(
Iridflare's expansion of the idea, in which we increase the rotational speed instead of make the bar longer, still puzzles me though.
Oh wait no I totally get it! The mass of the ends of the bar increases as the speed increases, which means you need to pump more energy onto revolving them faster, and then we're back at the whole "you need infinite energy" thing. And presumably the whole mass approaching infinity thing would tear them off your contraption no matter what you were using.
Dammit, Einstein, stop spoiling everything!
2 Answers
- IridflareLv 77 years agoFavorite Answer
This is an old thought experiment attempting to achieve ftl travel. If you google "long rotating bar ftl" you'll find lots of discussion about it.
- Ray;mondLv 77 years ago
The direction of down would be reversed everywhere except within about one millimeter of the North and South poles, so this would be the only places towers could be built with materials that exist at present.
