With the arrival of Aurelion Sol, it is now confirmed that outer space is indeed a physical reality, and that Runeterra exists as a planet much the way Earth does. So I suppose one of the big fat questions I have now is, are the Void and Outer Space the same thing? Or are they separate?
The Void is a realm on its own and its not the space, dont pay attention too much at Cho'gath's lore its outdated because it was during the start of league where the void was just ''not runeterra''
Space is not the Void, it has star stuff in it.
I think the "Void" is just an area in outer space, not outer space itself. There actually is an area in space called "Boötes Void". It could hold up to 10 thousand galaxies but only about 60 have been found to this day (don't take the numbers for facts, I am writing this off of my memory about this topic).
This may explain why many Voidborns are alien-like
I doubt that,space isn't purple enough.
On a serious note,it would be weird for the void to be outer space,i mean why would creatures like 
have the abilities to burrow if they are from a place without ground?
The void seems more like the place that is between dimensions.
