tsturm1967

I am sorry. I did not mean to upset anyone. I did get the answers I deserved though because it is a rather silly notion - an uncrossable moat, unbreakable barrier: Whatever. The point is, that there wasn't a "construction order": this does not mean the problem was poorly specified. If you read my first post, you already have the solution, though. Having a barrier in any shape or form that is "uncrossable" by principle simply amounts to asking "could there be a place in the universe that is completely unreachable?" - even black holes "evaporate" in time and thus exchange radiation with their surroundings. It is not uncommon for them to collide - enabling us to directly measure gravitational waves. Any effect on one side of the "barrier" must have a cause on the other side - and vice versa. Whatever your assumptions on an "inside" of a black hole: it is clearly affected by its surroundings: thus, the event horizon does not qualify as an impenetrable border. For my part, I came to the conclusion that such a barrier is theoretically impossible as it would lead to consequences which would simply violate the conservation of energy.This was just not the first notion I had. First think, then write. Sorry folks. Case closed.

A) I am not betting - I would not "loose" a million either way: either there is a way to build an impenetrable wall: in which case there would be something like a perfect fortress. Interesting. Or someone comes up with some proof that there will never be such a thing. Also interesting. Either fact could make you more than 1 million. B) Yes, but anything in a black hole would not be in need of protection. I suppose you could arrange black holes so their event horizons touch - and hide behind that wall. Just whether such a "wall" would be stable in itself... @Daecon: you see, if something got though it, it wouldn't be a good wall. If nothing gets through it, you can build a container where "inside" wouldn't actually interact with outside in any way shape or form. Or rather - my requirement is only that "outside" can not interact with "inside". "Why do you think it wouldn't be possible?" I don't. I'd be surprised, though, nonetheless. Just thought It'd be a nice thought experiment. I do not think it is poorly specified either. Can there be a barrier that can not be crossed nor destroyed ? If you think B gets close....well the close-packing of black holes isn't going to be very stable - hurl any kind of heavy object at it, an some of the black holes would move - creating a gap in the wall. If it was that easy, I wouldn't have bothered..

I propose the following challenge: let's build a fortress. Would it be possible to create a wall using the laws of nature so as to make "breaking it" not even an option? I'd guess it'd be a safe bet on kickstarter for a nice price: one million for anyone who proves is is not possible - or for an idea to make it possible. Would be interesting to find out what's on the other side of that wall, once its cut off from the universe ;-) Kind regards, Thomas