Any "canopy" of water sufficient to contribute to a 40-foot deep layer of water over the whole surface of the earth would have blocked out virtually all the sunlight, leaving the surface of the planet in constant darkness, or else it would have required an atmosphere which extended over 40,000 miles into space. Not to mention the havoc it would have played with atmospheric pressure. It's a scientifically untenable idea on every level, and is dealt with adequately at http://www.fsteiger.com/canopy.html and at TalkOrigins, http://www.talkorigins.org/faqs/canopy.html and http://www.talkorigins.org/indexcc/CH/CH401.html.

there is a excellent video on you tube offering a very sound scientific exaplanation to prove that the "water canopy theory" is not only plausible most did nost likely occur. It would have completely blocked out the UV rays. You also have other biblical evidence proving this. Before the flood,the people normally lived for hundrds of years, and after the flood the life spans dropped dramatically to the maximum of 120. When you think about it, it makes a lot of sense: the absence of uv ways before the water canopy collapsed did not limited the human life span. The intergration of uv rays after the water canopy collapsed started to affect the human life span. now, as to the question of carbon dating. Carbon dating is done only on surrounding soil, and never on structures or animal/human remains. Every single carbon dating that has ever been attempted on dinosour bones and "cavemen" remains have yielded a maximum age of approximately 13-14000 bc. when you do a bible based timeline and couple it with known migration, earliest writing, earliest settlements you get a time period for the beginning of life on earth and that age is 13-14000 bc. remember the cavement that was found in france, i can't recall right now it's scientific name. the scientists claim that they have carbon dated him to millions of years ago. the fact is that the carbon dating shows a age of approximately 100+ years, most likely from the late 1800's. Secondly, they claim that his flat forehead and facial characteristics were indicative of human evolution. The fact is that near where he was found there are other people who have similar facial and head characteristics, and that what this individual probably had was some kind of severely arthritic condition. it boggles the mind that scientists continue to delude society with the evolution theory even after knowing that there has been to date no carbon dating to prove it.