My thanks to Steven Timm who wrote this. Date: Mon, 2 Jul 90 23:53:54 EDT It was suggested
My thanks to Steven Timm who wrote this.
Date: Mon, 2 Jul 90 23:53:54 EDT
It was suggested a while ago that someone calculate the amount of water
required for a global flood which would cover the highest mountains.
Most probably the poster knew (as I do) that this calculation is already
done in Strahler. But since I don't have Strahler with me, I'm doing
the calculation for myself. After I answer the question, I'll go
on to calculate the first-order objections to the calculations that
creationists including myself would otherwise raise.
AMOUNT OF WATER ON THE EARTH TODAY: (EB is Encyclopedia Britannica)
Ocean volume: (EB 25:125) 1.37 E09 km^3.
Ice cap volume: EB 1:440
3 E08 km^3 of Antarctic ice. Antarctic ice is 90% of all ice, and ice is
.9 the density of water (can be denser under high pressure, but I believe
it's a second order effect.)
Thus 1.67E09 km^3 of water is available to make a flood.
Why no more? Water is massive enough so that it won't make escape velocity,
unless pushed to high temperatures. (RMS vel 100 C is 700 m/s, esc. vel
is 7000 and some. Thus whatever water was here still is here.
AMOUNT OF WATER TO COVER EARTH UNIFORMLY TO A DEPTH r.
With earth of radius R=1.2 E 7 m, the volume of water to cover
a perfect sphere to depth r above its surface is
4/3 pi *( 3 r * R^2 + 3R* r^2 + r^3). For the cases I will consider,
R>>r and only the first term is important.
Cover Mt. Everest: (8900 m) 1.6 E10 km^3 of water needed. If oceans
were present depth, add an additional 1.37E09.
A first-order correction is that we must consider the volume of land
mass above sea level. But it's clear there's not enough water
to go around.
The first Creationist objection would be: How do you know Everest was
that high during the flood?
All right. Let's take Mt. Ararat (3900 m) which the Bible says the
ark landed *on the top of*. For waters that high, 2.78E09 km^3 of
extra water is needed.
If all this came from forty days and forty nights of rain, this would
mean a flow of 821 km^3 per second. Whether from "fountains of the deep
or from above, the average precipitation would be 1.1 mm /sec or
~6 cm/minute (assuming uniform depth build-up to 3900 m over the
40 days, not quite correct)
From here on creationists must play with the initial conditions.
In particular, if someone suggests that all continental drift
and most mountain formation happened during the flood, and perhaps
the ocean wasn't as deep then as it was now, let's calculate
how shallow the ocean would have to be.
Take ocean surface area 3.6E8 km^2, mean depth 3.8 km. (now).
Reduce ocean depth to 1 km, say.
Now only 3.6E8 km^3 of water is needed to fill ocean, rest
(1.2E9), is available for flood, enough to flood earth uniformly
to a depth of 2.7 km.
I won't claim that the above scenario happened. Some will, or
variations on a theme of that. Point is, where they are free
to use the Bible to pick their initial conditions, they can
come up with volumes of water that are at least on the right
order of magnitude. So there's the science and speculation.
Take it for what it's worth.
Share and enjoy,
E-Mail Fredric L. Rice / The Skeptic Tank