What is the Biblical Basis of a "water canopy", and is there scientific evidence to support it?

Let's see how a master exegete, St. Augustine, approaches this problem.

In his day, a prevailing scientific theory was that heavy elements (water and earth) seek their "natural place" toward the center of the earth, and lighter elements (air and fire) seek their "natural place" toward the heavens. So, how can there be “waters above the firmament” (Genesis 1:6-9)? The waters being "above" is not their natural place; how can they stay there?

St. Augustine in The Literal Meaning of Genesis, lib. 2 cap. 4 n. 7 writes:

Taking these theories into account, a certain commentator [St. Basil] has made a praiseworthy attempt to demonstrate that the waters are above the heavens, so as to support the word of Scripture with the visible and tangible phenomena of nature… Hence, from the existence of the air between the vapors that form the clouds above and the seas that stretch out below, our commentator proposed to show that there is a heaven between water and water. This painstaking enquiry is, in my opinion, quite praiseworthy.

ibid. n. 9:

Certain writers, even among those of our faith, attempt to refute those who say that the relative weights of the elements make it impossible for water to exist above the starry heaven. They base their arguments on the properties and motions of the stars. They say that the star called Saturn is the coldest star, and that it takes thirty years to complete its orbit in the heavens because it is higher up and therefore travels over a wider course.

It is true, indeed, that by its own motion, moving over a vast space, it takes thirty years to complete its orbit; yet by the motion of the heavens it is rotated rapidly in the opposite direction…and therefore, it ought to generate greater heat by reason of its greater velocity. The conclusion is, then, that it is cooled by the waters that are near it above the heavens, although the existence of these waters is denied by those who propose the explanation of the motion of the heavens and the stars that I have briefly outlined.

With this reasoning some of our scholars attack the position of those who refuse to believe that there are waters above the heavens while maintaining that the star whose path is in the height of the heavens is cold. Thus they would compel the disbeliever to admit that water is there not in a vaporous state but in the form of ice. But whatever the nature of that water and whatever the manner of its being there, we must not doubt that it does exist in that place. The authority of Scripture in this matter is greater than all human ingenuity.

So, St. Augustine denies a leading scientific theory of his day in favor of the "authority of Scripture," which "in this matter is greater than all human ingenuity." (source).

We have it even better today because modern astronomy has been able to detect, with radio telescope spectroscopy, the chemical signature of water in interstellar gas clouds.

_{cf. also Galileo Was Wrong: The Church Was Right (vol. 3) by Robert Sungenis, which is devoted to history and Scriptural exegesis; e.g., pp. 560 ff., where he quotes St. Augustine's [Literal Interpretation of Genesis] to prove that Scripture has more authority than science}

Water suspended in zero gravity would be frozen as ice crystals and would not be boiling, the freezing cold temperatures of space would help keep the water from doing such. Also, one thing we all know about water is that it is translucent! This canopy could have diffused the light somewhat making the natural light at ground level less intense, which would actually be beneficial. It would also stop heat from escaping through the atmosphere thereby keeping the earth's temperature a consistent moderate-warm.

Clearly in Genesis 2:5, it did not rain at all at one stage of the Earth's creation - but rather it was watered from underground reservoirs of water which 'came up out of the ground'. Genesis 2:5 - "And every plant of the field before it was in the earth and every herb of the field before it grew - for the LORD God had not caused it to rain upon the earth, and there was not a man to till the ground. (6) Instead, springs came up from the ground and watered all the land."

Many claim that this is not evidence of it still not raining in Noah's time and that is very true, but the verse in Genesis 9:13 attests that it still did not rain right up until the time of the flood. Genesis 9:13 - "I have set my rainbow in the clouds and it will be the sign of the covenant between me and the earth. (14) Whenever I bring clouds over the earth and the rainbow appears in the clouds, (15) I will remember my covenant that is between me and you." Obviously for a rainbow to appear, there needs to be clouds of water in the sky which means that during Noah's time - there were no clouds in the sky! No rainbows occurred because all the water above the earth was suspended well above the sky/atmosphere itself.

Also we are told in Hebrews 11:7 - "But by faith, when Noah was warned about things that had never been seen, he built an Ark to save his family." Clearly things like rain and storms and such had not been seen whatsoever in Noah's time. The Bible clearly tells us about 'floodwaters in the heavens' (Genesis 7:11) that were there in Noah's time and that they 'opened' and the water came down causing the flood to happen. NO amount of clouds could drop enough water to flood the whole earth nor come anywhere close. Peter also mentions: (2 Peter3:5) "God made the heavens by the word of his command and he brought the earth out from the water and surrounded it with water.

The idea of a canopy of water comes from Genesis 1:6-7 (KJV), which says,

"And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. 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."

Read literally, it means that there is liquid water on the other side of the firmament (solid surface of some sort), which would--according to models that incorporate this theory--be emptied back onto the earth in the flood.

As mentioned, there are pretty significant scientific problems with this model, and I think most modern creationist models would tend to favor a "soft" firmament, which would mean that they consider the "firmament," which God calls heaven, the entire sky and outer space beyond. In this model, water and the celestial bodies aren't placed on a surface of the firmament, but are spread throughout the firmament.

In Genesis 7:11, we read:

11 In the six hundredth year of Noah’s life, on the seventeenth day of the second month—on that day all the springs of the great deep burst forth, and the floodgates of the heavens were opened.

The implication here is that water came from two directions - springs from the deep (i.e. underground water) and from above (the floodgates of heaven). Extending the metaphor ever so slightly, a floodgate is holding something back - according to the Institute for Creation Research, that is the canopy.

The Institute for Creation Research has published this paper to explain the physics behind it:

This study, however explains some of the problems. Amongst these problems:

• A water canopy of more than about 40 feet would, by the pressure, boil itself away
• A water canopy of more than a few inches would also block all the sunlight.

In the link, however, the paper argues that these problems are not insurmountable depending on the assumptions made about the canopy, but I'll admit, it gets a little stretched for my tastes.