you are correct mk5, explosion of starts give birth to asteroids, planets... and we all know that during that explosion gases are released, but eventually form chunks of matter, ultimately asteroids, and planets. but that does not explain the expansion of space, because expansion of space is entirely independent of exploding starts.
73% of everything that's there is space, planets and stars only make up about 3%, logically there is no way 3% can infulence 73%
This wont be the reason of universe expanding but if we imagine that that like layers of earth there are different layers in our universe as the explosions in our universe the matter gets spread through and that matters remains there and gets expanded...".Also universe is getting cooled and amount of matter getting increased as amount of matter getting increased the matter is added into our universe and it gets expanded"
oh! thanks... you need to understand that there is no center of the universe, that means there isn't layers of the universe otherwise there would be center layer, which is clearly not the case. second thing is you need to also understand that matter (galaxies) are not getting bigger and are also not moving, only space between the is getting bigger.