Hello I am trying to get into physics and astronomy as a hobby so please excuse the crudity of my posts, I regrettably have no physics education past high school level but nevertheless I aim to slowly but surely learn either self-taught or through some further eduction whether at college or university level. I have a few questions I'd like to ask of those much more learned than I: Say an astronaut is in space without a space suit. The astronaut starts a song on his iPod and puts his earphones in; will he hear anything? I assume there would still need to be air (or another medium for the sound to travel) between the earphone and the astronaut's ear/eardrum? Secondly, is it reasonable to assume that, given the magnitude of the universe, it could have already come to an end just, the light hasn't yet travelled to the Earth? I know that currently it is thought that the universe will end in some sort of big regression so therefore it's probably unlikely to already have happened (in this manner), or is it? Thanks!