One the quick quips that is out there today against traditional Christians beliefs in heaven as a place distinct from earth usually is: "oh that's dualistic/platonic/gnostic." I've handled this critique before in a 6 part series (starting here). Certain there is a gnostic and plantonic views of heaven. But first-century Christianity (and beyond) and Second Temple Judaism did belief that heaven was a place distinct from the earth (at least for the time being until the final New Heavens and New Earth).
I recently finished Jonathan Pennington's Heaven and Earth in the Gospel of Matthew. He states it this way:
The addition of τῶν οὐρανῶν to βασιλεία in Matthew makes it inevitable that some sense of a spatial understanding of the kingdom is communicated: understanding ἡ βασιλεία τῶν οὐρανῶν as meaning only the reign or rule of God in a non-spatial sense fails to account for the importance of Matthew's ascription of the kingdom as τῶν οὐρανῶν.
To flesh out this statement, we may observe that heaven does indeed regularly have a spatial sense in Matthew and therefore it is logical to see the same in his phrase ἡ βασιλεία τῶν οὐρανῶν. The ancient notion of heaven as a place is to modern, "enlightened" scholars either a source of embarrassment or derision. In response, many prefer to construe the notion of heaven theologically as a symbol. Regardless, it is undeniable that for most ancient people there was some real sense in which heaven was a place distinct from earth. Hints of this can be seen in the strong semantic overlap between the invisible heavens (God's dwelling) and he visible heavens above. Additionally, the OT and Second Temple literature testify that heaven was understood as the place of God's throne (a symbol of his kingdom), the place of God's angels, and the place from which God spoke and issued help and judgment. The NT evidently shares this worldview. Matthew is no exception. It is clear when Matthew refers to the Father as ἐν τοῖς οὐρανοῖς, this must have some sense of a dwelling place distinct from earth. [Pennington, Heaven and Earth in the Gospel of Matthew, p.296-97]
Pennington is quite clear that "the Christian hope is not for an ethereal heaven-situated existence, but the consummation of the heavenly realities coming into effect on the earth; not for the destruction of the earth and a kingdom that only exists in heaven, but for the παλιγγενεσία, a new genesis (19:28). [p.326-27]
Pennington is quite clear that heaven and earth are distinct--or as it is often slandered 'dualistic'.
Pennington's overall point is to come to a better understanding of what the phrase 'kingdom of heaven' means Matthew's gospel. He shows it part of an overall theological construct Matthew articulates. So it becomes clear Matthew does not use 'kingdom of heaven' where heaven is just a circumlocution for 'God' out of divine reverence--an older thesis now debunked by Pennington. Most notably, I think, is Pennington's argument that Daniel 2-7 with its contrast of the kingdoms of the earth vs. the kingdom of God that comes from heaven--the location of God's throne--serves as a background for Matthew's construct. He then argues that this notion of the kingdom of heaven would undermine common Jewish notions of the kingdom that looked largely for an earthly defeat of the Romans, but also serve latter Christians by assuring that their main focus was not rebellion against Rome by the earthly sword.
Pennington's carefully treatment and whole book is worth reading.
But we sight it here as one more debunking of the fanciful post-enlightenment neo-Christian reworking/rejections of a traditional view of heaven.