It's pretty impossible to guess what ancient people believed and didn't believe. I know that the Bible and other ancient texts suggest that hell is a holding place for dead spirits, not a place of torment, and that it's not underground or anything like that. I know that there is a lot of symbolism used as well (do angels have wings or are they symbolic of the ability to move from place to place without having to walk?) Where is heaven? Not on Earth. So what's not on Earth? The sky? Stars? Is it symbolism or is it "they live in the clouds"? I don't remember the bible saying that they live in the clouds, only that they live in the heavens... and the heavens meaning the sky, stars, planets, and all that encompasses. Was their understanding of the heavens that it was finite? That it had limits? I don't know.
The other thing to question is did it matter? If I needed you to fix cars, would I bother explaining to you how to make an airplane? Could God have given the information necessary for their time, for their purposes, for their progression and to lift the people who they interacted with at the necessary interval? I mean, I don't have a problem with a God who looked at humans and said "okay, they're ready to accept this elementary information. They're not ready to understand the cosmos. They don't need to understand how gravity, orbits, or even how large the universe is. We'll leave it at that until they're ready for more."
It would be a pretty stupid God who went to a bunch of people unable to understand these things and explain everything, and then watch His prophet basically be ignored about the more important spiritual things because they considered him a madman to be talking about the universe. Look what happened to Galileo so many centuries later. We're given what we're ready for when we're ready for it.