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OK, so most people of neutral, skeptical or commonsensical persuasion understand that the global flood claims of Genesis are nonsense. Yet the meme still persists amongst literalists and fundamentalists. I love GearHeadEd’s comment over on DC. It shows that that much water is truly a ridiculous concept. I wrote extensively once on why people believe such silly things. Here is Ed’s comment:

Here’s a very detailed presentation of a theory as to how the Noachian Flood happened. First, there isn’t that much water available on Earth, so where did the water come from?

A hypotheses has been put forward that the earth was struck by a number of comets which delivered the requisite water to earth, hence the flood. You gotta be fakkin’ kidding me! It pains me knowing that I live in a country where people can propagate this kind of thing (and worse, be believed!) so I started to work out a some calculations based upon fairly simple math (albeit with some very large numbers) and high school science. So how big would the S’Noah ball have to be?

Ok then. The Bible claims that the entire earth was covered in water. So how much water is that? A simple approximation can be calculated .

Assuming the world is only 6000 or so years old then it stands to reason that Mount Everest was pretty much as we find it today, give or take. To cover all the land on earth requires enough water to raise sea level another 8848 meters (height of Everest). Should we throw in 3 extra meters just to prevent anyone from standing on their tippy toes? You have to be sure everyone drowns don’t we? Naw, that variable will get swallowed in significant digit rounding errors anyway.

Next, we need to calculate the volume of the earth at sea level. Now I will use the diameter at the poles not the equator. I know what you are thinking – that underestimates the volume a bit because the earth is bulged at the equator. Have no fear. I chose the smaller number because then I can discount the variable volume caused by topography and still have a conservative estimate.

Diameter of the earth at the poles ~ 12,715.43 km so the radius ~ 6378 km.

The volume of a sphere is 4/3 Pi*r^3 or in this case 1.33333…*3.14159…* (6378^3) or roughly 1,086,780,374,578 cubic km. This number will be subtracted from the volume of an earth-sized body covered by an additional 8.8 km of water to determine how much water has to be delivered by this comet(s).

Add 8.8 to 6378 and we get ~ 6387 km for a volume of 1,091,387,539,146 cubic km.

Eliminating the volume of the earth pre-flood, we end up with 4,607,164,568 cubic km of water required. DOOH! That seems like a lot of water. So let’s put it into some perspective. Dividing this number by 3/4Pi and then taking the cube root you end up with a blob of water roughly 2064 km in diameter or fairly close to the diameter of Pluto (2274 km). That IS a lot of water! All right – there are things that big out there in the Kuiper Belt and Oort Cloud so I guess one of them could strike the earth.

But let’s see how much protection an ark would need to survive such a thing. Now I know you are saying “DUDE – the Bible says it rained 40 days and 40 nights so it all didn’t have to hit all at once”, but the amount of total energy delivered stays the same no matter how many individual packets are involved. To be generous let’s divide this blob into 80 parts; one for each night and day…

That means that twice a day 57,589,557 cubic km of water struck the earth.

But let’s just use the total to make some estimates. To this point the faithful can say that “yeah, that could have happened”. Maybe. But now we need to calculate what WOULD have been the result of such a collision(s).

There’s this little problem with energy conservation that they seem to have ignored… We have to account for the energy transferred to the earth and its atmosphere by way of such a collision.

HOW MUCH ENERGY ARE WE TALKING ABOUT?

Kinetic energy is determined by 1/2mv^2 where m=mass and v=velocity for a point object with no rotational energy. (Let’s keep it somewhat simple and ignore rotational forces for now…

A cometary body striking the earth is usually given a velocity around 25 kps (kilometers per SECOND!)

The mass of water is 1000 kg/cubic m. There are 1,000,000,000 cubic meters in a cubic km so we have 1,000,000,000,000 kg of water / cubic km. (see where we are going with this yet?) Multiply this by the amount of water we determined was

needed and what do you get?

4.61×10^21 kg of water.

That results in 1.44×10^30 Joules of kinetic energy! That is roughly how much energy would be absorbed by the earth to stop a 2000+km diameter ball of ice. And it has to be to stop it or else the water doesn’t fall to earth.

That seems like a lot of energy to get rid of – particularly when you consider that 3.34×10^31 J is how much the sun produces each day and 5.5×10^24 J is how much total solar energy strikes the earth each year! Another comparison is

that it would be equivalent to 5.46 Trillion Hiroshima-size atomic bombs (a little more than 15,000 of them per square kilometer–that’ll leave a mark!). Or, if you prefer, the total energy delivered to the earth by the asteroid at the end of the Cretaceous period was at least 10 million times less… I don’t care how many cubits the ark was I doubt a wooden boat could weather that storm…

That isn’t the end of our problems – how do you mop up all that extra water when you are sure everyone is dead?

AHA!

Tricked ya because all that energy would have flashed the water to steam and exploded out into space leaving a surface of molten rock! Oh, that might not bode well for poor old Noah and clan…

Still think a Flood actually happened?

(Hat Tip to Pliny the In-Between…)

Such comet as causing flood theory has been detailed elsewhere. But it is wholly problematic, as you can see.

Jonathan MS Pearce

A TIPPLING PHILOSOPHER Jonathan MS Pearce is a philosopher, author, columnist, and public speaker with an interest in writing about almost anything, from skepticism to science, politics, and morality,...