look how the verse separately mentions the earth, what does this indicate?

that the earth has been separated from the a sewed up entity, so we can live on it? where are you gonna live, in space? every scientist will tell you that some sort of mega star exploded leading to the creation of the solar system literally one entity ripped apart into more things

the earth is separated from the universe

made clear barriers that separated us from the dangers of the universe, we live on earth, atmosphere, magnetic fields to protect from UVs are means that sperate us from the universe cold, death causing mechanisms.

the lowest heaven is adorned with stars

lowest heaven can also means the closest, the word used is dunya. dunya is the lowest and closest but a delusional "heaven" to us,

Meanwhile the earth and heaven separating myth prevailed befire mohamed...

according to some scholars there were over 284,000 messengers sent to humanity. we only know of 21, then since there is no way to keep the record straight, truths got mixed with falsehoods then you end up having polytheism. how many messengers were sent to bani israel?