I'm not...."And God called the firmament Heaven"
Fair point, I need to explain myself better. I use modern science to understand what the world actually is. I am well enough versed in science to know to take things skeptically and not just believe whatever scientists say (e.g. evolution), but have also looked into this carefully enough to conclude that the earth is not flat, it's round, floats in space, stars are a long way away and all that - basically, the universe is roughly as astronomers describe it. Their accuracy will diminish the further away you get, some things that are believed today as fact will be shown tomorrow to be incorrect, but the basic idea that the earth is a ball moving through a space that contains other balls in it is correct. So, knowing that, I look to Genesis to see where it all came from.Which is the problem with most of what you said about heaven, you're reading modern astronomy into the creation narrative.
"Heaven" = "shamayim", meaning sky, abode of the stars, abode of God.
From God's perspective, He knows the full extent of the Heaven, and He created it all.
However, when we look up, at the Heaven, we see the atmosphere. For a man without a spaceship, everything up is "heaven".
So God created the firmament, this layer surrounding the earth with water above and below it. But man at the time could never actually see it as something distinct from the rest of heaven. Whenever you look up, you see "heaven" - and God named what you see when you look up "heaven".
In the same way, God called the light "day" and the darkness "night". In astronomical terms, a "day" is meaningless - it doesn't actually affect anything other than the earth, because it is caused by the earth's rotation. Day and night exist simultaneously, and light exists even when it is nighttime (we are just in shadow). Nevertheless, God spoke to man from man's perspective, and "called the light day", because when man looks up and sees the light from the sun it is daytime. Now, in reality, the light from the moon is that same light, and we don't call that light "day". We don't call the light from the sun hitting a spaceship "day". We only use the word "day" when we are on a planet and talking about the light as opposed to the darkness of night.
So when God created something, He made what truly exists.
But when He names something, He does so for the benefit of man, because the name is being given to man to use, and therefore the name he uses is related to man's perspective, a useful day-to-day term for humans to use, but not necessarily an accurate scientific description of the whole.