Several months ago I've stumbled an interesting question about the Ripple system: How does Ripple solve the double-spend problem?
Specifically about how double-spending is solved in Ripple. As you can see only @David Schwartz replied to my comments and only he was able to give an answer, given that I think he works for Ripple.
But if he's right, this would be revolutionary in a way, since Bitcoin electricity wasting mining could be replaced by this system.
In any case, my question is: can Bitcoin mining be replaced by a Ripple sort of system? How would that work?