Just as with cars, it's critical to know the fuel efficiency of black holes. Without this information, we cannot figure out what is going on under the hood, so to speak, or what the engine can do.  -   Steve Allen     Quotes
Just as with cars, it's critical to know the fuel efficiency of black holes. Without this information, we cannot figure out what is going on under the hood, so to speak, or what the engine can do. Steve Allen
 Efficiency