"The Hebrew Universe:
"The ancient Hebrews imagined the world as flat and round, covered by the great dome of the firmament which was held up by mountain pillars (Job 26.11; 37.18). Above the firmament and under the earth was water, divided by God at creation (Gen 1.6, 7; cf Pss 24.2; 148.4). The upper waters were joined with the waters of the primordial deep during the Flood; the rains were believed to fall through windows in the firmament (Gen 7.11; 8.2). The sun, moon, and stars moved across or were fixed in the firmament (Gen 1.14-19; Ps 19.4, 6). Within the earth lay Sheol, the realm of the dead (Num 16.30-33; Isa 14.9, 15).” (pg 339) [see picture below]
"Firmament:— Achtemeier, Paul J (Ed). The HarperCollins Bible Dictionary. (New York: HarperCollins, 1996)
“The Hebrew term raqia’ suggests a thin sheet of beaten metal (cf. Exod. 39.3; Num 17.3; Jer 10.9; also Job 37.18)… Job 26.13 depicts God’s breath as the force that calmed (or ‘spread’, ‘smoothed’) the heavens. Luminaries were set in the firmament on the fourth day of creation (Gen 1.14-19). Rains were believed to fall through sluices or windows in its surface (cf. Gen 7.11).” ( pg 338-339)
Other artistic variations on a theme: how the ancients spoke of the universe in poetry.
NOTE: I just found these drawings online and I cannot vouch for the truthfulness of ANYTHING on their original websites. Let the reader beware.