Maybe you failed science, but if youre unaware, there is nothing to carry sound in space. In some of the commercials, they actually did leave sound in to create a sense of interest with modern audiences through destruction. Its essentially a marketing ploy that was reversed for the final cut, and wisely so. There is a sequence during Gravity where a station is blowing up and falling apart, and as this carnage begins flying in every direction, you realise that theres no sound from the explosions or surrounding carnage. Its a visual that cant be put into words, but these sound design decisions add to the atmosphere in chaotically beautiful fashion.