"In biblical cosmology, the firmament is the vast solid dome created by God on the second day of his creation of the world to divide the ...
[Read more]
primal sea into upper and lower portions so that the dry land could appear. The concept was adopted into the subsequent Classical/Medieval model of heavenly spheres, but was dropped with advances in astronomy in the 16th and 17th centuries. Today it survives as a synonym for "sky" or "heaven"." - (en.wikipedia.org 17.07.2022)