Thanks for pointing out that shamayim - the -im ending - makes the word plural as it does in elohim - the gods. From my biblical studies, my understanding of "god" (eloah) or "gods" (elohim) is they are any beings more capable or "advanced" than us humans. In today's parlance, these are ETs - intelligent beings from the heavens. Our common reference to "heavens" is "space", and we also have three "layers" of them just as the ancients did: 1) troposphere, where birds fly, tree leaves fall, and weather occurs; 2) outer space, where the planets, stars, comets, galaxies, dust clouds, etc. are; and 3) "the third heaven"; perhaps it might be called eternity - beyond the universe - or perhaps not. Scripture does not tell us the scope of the creation, though it is commonly assumed that it is the entire modern cosmological universe from cosmology. But that is an assumption.
Indeed, the entirety of what is contained in the modern cosmological model is the work of God, but we have enough trouble with the Greek philosophy imported into Trinitarian doctrine to know the totality of what is to be known about God. Could it be that the Genesis 1:1 text about the creation of "shamayim (sky) and erets (land)" might be lesser in scope than our modern conception?