In the trailers we see clips of people dangling from the corridors (no doubt including Kirk, him dangling from things is the new shirt-ripping), a woman falling, and one shot of Scotty holding on by one hand in engineering, as the Enterprise's gravity is tipped 90-degrees. It looks incredibly cool. But what could do that? Artificial gravity failure close to a planet? Or while moving at sublight? Or some sabotage or malfunction of the ship's artificial gravity generator (if there is such a thing) cranking "down" 90-degrees from where it should be? Speculation commence!