^ rāqîaʿ
"...the firmament is the vast solid dome created by God on the second day to divide the primal sea (called tehom) into upper and lower portions so that the dry land could appear..." --
https://en.wikipedia.org/wiki/FirmamentPossibly the most solid thing in the universe is the dome. The dome is, essentially, empty space. It reaches throughout all material into the emptiness where material barely exists. It is many light-years "high," and contains all material things, flowing through them.
This is what is said in Genesis chapter 1, especially verses 6 thru 9. How do we know that Genesis says this, even though Genesis doesn't talk about light-years? Because we have found that it is light-years in fact. So, that is what Genesis is saying.

Says who because that is not what is written.?
KJV
Gen 7 And God made the firmament and divided the waters which were under the firmament from the waters which were above the firmament and it was so
Gen 8 And god called the firmament Heaven and the evening and the morning were the second day.
Gen 9 And God said, Let the waters under the heaven be gathered together unto one place, and let the dry land appear: and it was so.
So your saying Heaven is light years high?
In answer to your question, kinda no. What I mean is, if you are standing at the North Pole, the heavens are light-years high above you and the North Pole. But they aren't light-years high above the South Pole, because the South Pole is "under" you almost 8,000 miles, and the heavens that are light-years away in the direction of the South Pole, are light-years "low"... at least until you go to the South Pole. Then the heavens are light-years high above you.
Remember that St. Paul talked about being caught up to the third heaven. We have 3 heavens in simple general. The first is a layer that is the atmosphere above Earth, and it includes what we call inner space where the ISS orbits. The second is the thing that we call outer space.
The third is God's heavenly home: Heaven is God's throne; the earth is His footstool. His heavenly home is a "space" outside of the universe, that essentially "surrounds" the universe.
