The firmament in Genesis 1 is solid, and it’s supposed to be, because it’s the ceiling of the cosmic temple.
Would be more helpful to acknowledge this is just ONE version? Or perhaps that
is why you specify the “firmament in Genesis 1” as opposed to the other descriptions
Even rabbinical “schools” seem to vary as to whether there is more than one “firmament” or “floors” of the upper heavens.
And we should acknowledge that the ancients were less concerned about having One Single Answer, and more concerned about having All the Various Answers.
Gods could be many things all at once. The firmaments could be different things all at once. Don’t the books of Enoch present territory above the firmament? My apologies… I don’t recall the specifics.
There is a transcript of this very interesting YouTube video! Just click on the 3 dots to the right of the word SAVE:
There’s also a closed captions button which will display the words onscreen as they are spoken. It’s automatic text to speech, so it’s occasionally a little wrong but it’s pretty accurate.
Once more I am reminded of the story “Tower of Babylon” by Ted Chiang. You should read it, so I won’t provide spoilers. It’s in this book Stories of your Life and Others.
That is why I specified “the firmament in Genesis 1”.
Nevertheless, in the Old Testament there is only one. It is hardly referred to at all (only 17 times), and every instance is in an exilic or post-exilic text (nine in Genesis 1, five in Ezekiel, one in Daniel, and two in the Psalms).