I’m not sure why, but a lot of people seem to have a really hard time looking up information about stuff from the Bible. I remember probably about a year ago not too long after I first joined Lemmy commenting on a thread from some guy whose sister fell into some fundamentalist Christian flat earther bullshit and he was trying to figure out where she got her info from and said that he couldn’t find anything about “the firmament”
It’s on like the first page of the Bible. And just googling “firmament” will get you plenty of good sources about the firmament and what it’s supposed to be.