Re: 50%

This "authority" can just connect to some different points of network and log the blocks.

When the majority of the network is reporting one set of blocks as being accurate, and the minority is reporting a different set as accurate...

Wouldn't the authority automatically assume the majority?...

Looks like you don't get the idea.
That's the whole point of the service - to detect presence of the other set.

Detection is not a solution.

Prevention is.

Think of it like AIDS
By the time you 'detect' it
It's DEFINITELY too late.

Just because an attack is implemented doesn't mean it will succeed. Just because someone introduces a modified block chain doesn't mean that will get accepted. Knowing nuclear missiles are coming at you gives you time to get to an underground bunker.

Yep, it gives you ~10min to sell your BTC off en masse before the collapse occurs

The price of bitcoin can collapse without any security issues on the network. There should be something to prevent this too.

We need regulation on this free market thing.