Why are so sure it doesn't end? Astronomers have sent satellites that have confirmed there is in fact a point at which space ends. But It expands so rapidly, and space is already huge enough as it is, that it would be impossible for humans to reach to reach it. Stars give off light. Satellites are able to pick up on said light. Eventually, there is a point where no light is produced. Therefore, there are no stars to produce light. As far as we can tell, the black nothingness beyond the universe goes on forever.