Im not an expert by any means. My understanding is that the universe is racing apart, outwards, like a balloon expanding, until eventually, everything has become so far apart, if we were to look up into the night sky, we would be alone, and nothing would be there.
Genesis doesnt explain it any better, in fact, it reads like any other creation myth from anywhere on earth:
'In the beginning, God created the Earth and the Sky.......', ' He created light before the Sun and stars'....., 'vegetation before the Sun'.