How long is a piece of string?
I don't think it's a set number of years but rather a period of time distinguished from other periods of times by, er... something distinguishing.
Ooh, I know that one, four and three quarter inches ...
Not really. Both are entirely dependent on a series of events; although, geological eras do have a tendency to be longer.Depends if it is a geological era or a calendar era.
Ah the classic comic classified ad. "FOR SALE - Piece of string: Length, as described"How long is a piece of string?
well era is a precise formula used to determine how many runs a pitcher gives up per game.
Actually, to be technical, an era is the number of runs given up every nine innings (or a projected number of runs for every nine innings). I don't think we'd want to see how many runs the fat toad would give up in a whole game.
How long is a piece of string?