There is a physics book on pinkie pie, its titled screw physics I'm pinkie pie. The book has 1037 pages and just says "screw physics I'm pinkie pie" over and over with a random picture of pinkie pie doing something random on various random pages
Y'know, this doesn't seem impossible given everything else she's done in the show. Very nice cartoony, and comical piece. Making her hair the "balloon" was kinda clever to, and a nice subtle reference to how her hair "deflates" when she got sad in "Party of One."