What is the correct name for the space between heaven and earth?
I thought of ether but it seems to have a prevailing chemistry meaning, whereas its second connotation is described by OxfordL as literary:
LITERARY: the clear sky; the upper regions of air beyond the clouds.
Plus, this doesn't seem to include the space below the clouds.
Then I thought of atmosphere, but its main meaning seems to be
the mixture of gases around the earth (Cambridge).
When I googled it, I found the definition of horizon as
the apparent boundary between the Earth and sky.
However, I am looking for the word that denotes the space in between, not the boundary.
I am making up this sentence:
She lost sight of the swans that vanished into the _______ .
The boy measured the ________ and wished that one day he could traverse it with a spaceship.
The examples I have given are rather orientative, not restrictive. If the word or phrase found doesn't go well in the senteces but means exactly this space between sky and earth, I'd be happy.
The word or phrase can be figurative, but I could also use a "technical term" for it.
Edit: My question is vague. Maybe it helps if I say just ignore the examples. Sky is too general a word, I would need something more specific, more synonymous of troposphere, without being necessarily a scientific word. If there are other scientific words, I do not reject them either.