As the Bible states clearly, there are windows between the edge of the firmament and the waters above (this is why the sky looks blue).
Genesis 1
6And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.
7And 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. 8And God called the firmament Heaven. And the evening and the morning were the second day.
Genesis 7
11In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened.
Genesis 1
6And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.
7And 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. 8And God called the firmament Heaven. And the evening and the morning were the second day.
Genesis 7
11In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened.
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