Heaven and the Heavens

For the authors of the Hebrew scriptures, "the heavens" are a physical reality. "Hashamayim" is plural in Hebrew, just as "heavens" is plural in English.

The Christian concept of Heaven is an eternal state of complete, perfect, everlasting bliss caused by unblemished union with God. "Heaven" in this sense is not a part of the physical universe at all.

The Heavens

Ps 19:2

οἱ οὐρανοὶ διηγοῦνται δόξαν θεοῦ ποίησιν δὲ χειρῶν αὐτοῦ ἀναγγέλλει τὸ στερέωμα

The heavens declare the glory of God; the firmament proclaims the works of his hands.

Heaven

2 Cor 12:2

I know a man in Christ who fourteen years ago was caught up to the third heaven.

God Himself dwells in the "highest heaven" (sheme hashamayim, the "heaven of heavens").

Hebrew constructs superlatives by using the bound form. So, for example, "King of Kings," "Lord of Lords," and "God of Gods" may be translated as "the highest King," "the greatest Lord," and "the supreme God." The "highest heaven" is "sheme hashamayim," the "Heavens of the Heavens" or the "Sky of the Skies." There is always a sky of sorts involved in our imagination. We cannot picture any thing at all without supposing (or imposing) a background and horizon behind it. Logically, there must be a highest heaven, a sky that bounds all skies, a background that has no background. And, as Thomas says at the end of each of His Five Ways, "and this everyone understands to be God." God is not in the Heavens; the Heavens are in God.

What we mean by "heaven" in ordinary discourse is union with God in eternity.

"Heaven" in this sense is a state, not a place.