Who the fuck thought up the idea of a 47" shelf?! Thanks Ikea!

Wall studs (joists to you brits) are spaced at 16" in the US.  As the yanks like to say "sixteen on center", though that mnemonic makes no sense to me, if it's 16" the 'on center' part seems superfluous, it's also 16 on edges ... but I digress.

Anyway, I'm in the middle of putting up shelves in Ben's bedroom and I pull out the shelves (from Ikea) and they're 47" long.  Now, that means I have to put the brackets 47" apart, in fact closer to 46" due to the design.

How does that make sense to anyone?  It means one bracket may be in a stud, but the other's bound to be dangling from sheetrock.  It's fucked-up.  Now I need to figure out if I can get some butterfly mounting things, and figure out how much weight we can put safely on these shelves.  No doubt books are out of the question.

Stupid, stupid Ikea.