Without physical ‘space’, there can be no physical existence.

Space, universe, galaxies, stars, planets, earth.
Without ‘space’, there can be no physical existence.

Without ‘space’ there would no physical existence because a physical thing, whether matter or energy, requires a space to exist in.
Therefore this ‘space’ had to exist before or come into existence at the same time as the physical things.
Since this ‘space’ contains physical things, it must then also be a physical thing.
‘Space’ in itself is empty...void of any matter or energy.
Therefore, ‘space’ itself cannot create anything, since there is nothing in it.
Since there is physical matter and energy in ‘space’, these physical things came into existence either at the same time or after physical ‘space’ came into being.
Since this ‘space’ is physical it cannot be infinite in size or eternal in time because all physical entities have a beginning and an end.
Our Milky Way galaxy is estimated to be 100 thousand light years in diameter. The observable universe is estimated to be 90 billion light years in diameter.
But these distances are uncertain since no one has actually technically seen the edge of the Milky Way galaxy or the edge of the universe (which contains millions of galaxies).
How big is ‘space’ then?
Some say infinite. But this is not possible since ‘space’ is a physical entity and environment.
How big is ‘space’ then?
It is at least as big as the universe which is contained within it.
Is this ‘space’ bigger than the universe?
No one can tell, since no one has technically seen or been to the edge of the universe (90 BILLION light year trip / i.e travelling at speed of light for 45 BILLION years going there and then 45 BILLION years coming back...even the sci-fi Star Trek Enterprise hasn't been there).
Therefore, this physical ‘space’ may be only as big as the physical universe.
What is beyond this ‘space’ then?
The Creator,
….He Who give existence to all that exists.
….He Who is the beginning and the end.
….He Who has always been, is, and will be. He Who is eternal and infinite.
….He Who is Good.