Diane Roy wrote:
> >AR As a Creationary Catastrophist I make no
> > appeals to unknown physics or miracles concerning
> Noah's
> > Flood catastrophe. You apparently missed previous
> posting
> > which proposes that the catastrophe was caused by a
> series
> > of asteroid impacts similar to comet Shoemaker-Levy 9
> on
> > Jupiter. I'm not at this point going to reiterate
> what I
> > said before. I believe that there are archives for
> that.
>
> GM
> No, I read the previous posts & know your asteroid impact
> idea.
> It attempts to make use of known natural processes but then
> tries to avoid
> the difficulties that idea encounters by saying (to quote
> your previous post)
> "their heat loss calculations are not going to be comparable
> to catastrophic
> conditions" - which I take to mean that their heat loss
> calculations aren't
> valid under catastrophic conditions. There is no reason to
> believe that our present
> understanding of mechanics, thermodynamics, radiation
> transfer &c aren't valid
> under the conditions which would obtain with an asteroid
> impact. If you think that
> there _are_ such reasons, or that the known laws have been
> applied incorrectly, state
> the reasons for such claims explicitly. Until you do you
> are appealing precisely to
> "unknown physics."
>
>
> AR: The "black body" radiation of planet earth is modified
> and tempered by the structure and make up of the
> atmosphere. The heat loss is modified by two factors, the
> layered structure of the atmosphere and certain molecules
> (H2O and CO2 primarily) contained in the atmosphere. As long
> as the atmospheric structure remains as it is, heat loss
> will remain the same over time. However, if a series of
> asteroid impacts were to strike, the atmospheric structure
> would be greatly disturbed. The distinction between
> Troposphere, Stratosphere and Mesosphere, etc. become no
> more (assuming that that was the same structure before hand)
> for a while. H2O and CO2 are primarily concentrated in the
> Troposphere. The mixing of the Troposphere with the rest of
> the atmosphere would dilute their concentration and allow
> for greater radiation. The lack of Tropopause, Stratopause,
> etc would result in much higher rise of warm air (closer to
> space) and result in greater facility to heat loss.
>
> Dust that is injected into this highly disturbed atmosphere
> is less likely to be retained there than in the high
> atmosphere of a stable atmosphere. But such dust will
> seriously reduce, for a while, the amount of light coming
> through the atmosphere and cause a serious drop in global
> temperature (the process known as impact-winter). Water and
> water vapor also injected into a disturbed atmosphere would
> not remain as long as otherwise in the high elevations of a
> disturbed atmosphere either. Thus the threat of the
> greenhouse effect is reduced. And, condensation of water
> vapor is most likely to occur in the high elevations of a
> disturbed atmosphere where the dust is. The generated
> latent heat will find easy release to space because of it's
> proximity to space rather than if in a layered, stable
> atmosphere.
>
> There is no appeal to 'unknown physics' here. I find it odd
> that some think one must appeal to 'unknown physics,' just
> because they are unable to think outside of the box they
> have closed around their minds.
Use of "unknown physics" can be either either an appeal for phenomena &/or
laws which go beyond presently established physics OR vague & generally qualitative
claims (what back in grad school we called "handwaving") that somehow when all the
complicated phenomena are taken into account things will work out the way you want them
to. The second use is most effective when you know beforehand the answer you want to
get - like the answer in the back of the book or a global flood. & this second type of
argument is what you've given in response to the detailed studies of an asteroid impact
which Glenn cited.
Take just the first of your arguments, that redistribution of CO2 & H20 in the
atmosphere would change the absorption of the earth's thermal radiation. As a first
approximation take a simple model in which N molecules are distributed uniformly in an
layer of atmosphere of height h << R, where R is the radius of the earth. The number of
molecules per unit volume is then n = N/(4*pi*h*R^2). If the cross section for a
particular scattering process by a molecule of a photon of a certain energy is s, the
mean free path of a photon is L = 1/ns = (4*pi*h*R^2)/Ns, which is proportional to h.
Thus h/L, the average number of times a photon would be scattered in passing through the
layer of moecules, is independent of the thickness of the layer. Or to put it another
way, the probability of scattering doesn't depend on the thickness.
This is a very crude calculation with a crude model, but it does suggest that
the effect you appeal to wouldn't make a significant difference. If you disagree,
present a more refined model & calculations based on it to support your position.
Finally, let's step back and look at the big picture. It seems to be agreed
that a single large asteroid impact would have a number of catastrophic effects on
terrestrial life. It would be a bit surprising, to say the least, if a lot of
near-simultaneous impacts had a _less_ catastrophic effect.
Shalom,
George
-- George L. Murphy gmurphy@raex.com http://web.raex.com/~gmurphy/
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