Outer Space is not a perfect vacuum
Think of it like a gas or plasma with a lower density than air near the surface of the earth but a higher density than zero
When light is red shifted it is assumed that an object is traveling away
Because all light coming to earth is red shifted relative to the expected emmission pattern it is incorrectly assumed the Universe is expanding
But as light travels through a medium it can be red shifted
The Universe is not expanding
Big bang is wrong