Is it possible that Bitcoin will be regulated? And if it will be, then how would we know

I have heard stories, speculating that if someone holds 51% of the total amount of BTC they will have kind of a monopoly position and can make or break the coin alltogether. Is this true?
No it is not possible that bitcoin will be regulated and if it was, there would be no way to know about it. It is like in China right now.