this glass dome a world apart with its visionary expanse of the Hudson in midwinter

[Coffee Break]

Hello everyone. I encountered this expression, "this glass dome a world apart with its visionary expanse of the Hudson in midwinter", but am struggling to understand it. Could you please let me know what it means in the following sentences:

So that it all came down to this, didn’t it—this moment, these tears, this dinner in a greenhouse, this party, this woman, this fire in my gut, this roof garden, and this glass dome a world apart with its visionary expanse of the Hudson in midwinter and that tireless celestial beam, which kept resurfacing each time you thought someone had finally pulled the plug on it and which now traveled the sky like a lazy presage of the many wastelands in store for me and of the wasted landfills straight behind—all of it added up to one thing: that if to some, being human comes naturally, to others, it is learned, like an acquired habit or a forgotten tongue that they speak with an accent, the way people live with prosthetic pieces, because between them and life is a trench that no footbridge, no corvus can connect, because love itself is in question, because otherpeoples are in question, because some of us—and I felt myself one in the greenhouse—are green card–bearing humanoids thrust among earth-lings.

- André Aciman, Eight White Nights, First Night

This is a novel published in the United States of America in 2010. This novel is narrated by the nameless male protagonist. The protagonist meets Clara at a Christmas party in Manhattan. Here, while being in the party, the protagonist is thinking about this party and the woman in front of him named Clara and the Hudson river.

Here, as for "this glass dome a world apart with", would that mean that the glass dome was detached from the protagonist by the distance of one world, because of the expanding Hudson river...? (Though this is just my guess. )

Also, I wonder whether "visionary expanse of the Hudson" means that the Hudson river was vast (=expanse), and that vastness was like a phantom/fantastical/unreal (=visionary) image.

I would very much appreciate your help.

 

[Skrej]

Here, as for "this glass dome a world apart with", would that mean that the glass dome was detached from the protagonist by the distance of one world, because of the expanding Hudson river...? (Though this is just my guess. )

They're eating in a greenhouse on the roof. Greenhouses of course are mostly glass or clear plastic, and this one is apparently a geodesic dome, or else the author is using 'dome' metaphorically for a rectangular greenhouse. It's like being on another planet compared to what's outside. It's winter outside and likely covered in snow, but inside the greenhouse it's lush, green, and warm.

Also, I wonder whether "visionary expanse of the Hudson" means that the Hudson river was vast (=expanse), and that vastness was like a phantom/fantastical/unreal (=visionary) image.

No, the view of the Hudson is expansive, not the river itself.

 

[Coffee Break]

@Skrej,

Thank you very much for the explanation and the link.
So it does not mean that the glass dome was spaced from the outside by the distance of a world; it would mean that the glass dome was an entire world by itself, which is separated from the outside world (=a world apart)!

And "visionary" would mean that only the view of the Hudson was expansive, rather than that the actual Hudson river was expansive.

Definition of VISIONARY

having or marked by foresight and imagination; of the nature of a vision : illusory; incapable of being realized or achieved : utopian… See the full definition

www.merriam-webster.com

: of, relating to, or characterized by visions or the power of vision

So the underlined part is describing that, a glass dome was a whole world, which is separated from the outside world, and the glass dome provided the expansive/broad/open view over the Hudson river, especially over the river's winterscape. (There was nothing blocked the view over the river, seen from the glass dome of the greenhouse.)

I sincerely appreciate your help, for letting me understand.