quote:
Originally posted by Tranquility Base:
^ Venus is vaugely suggestive of Baumgardnert's thesis - I doubt it was his killer point or his only point!
I think that you miss my point, here is the complete phrase from Dr. Baumgardners paper.
" A notible outcome of the recent high resolution mapping of the surface of Venus by the Magellan spcaevraft is the conclusion that there was a tectonic catastrophe on Venus that completely resurfaced the planet in a brief span of time. This event in terms of radiometric time, accounting for the uncertianties in the cratering rate estimates, coincides almost precisely with the flood event on earth. A mechanism internal to Venus was almost certianly the cause of the catastrophe. It is reasonable to suspect that simultaneous catastrophes on both the earth and Venus were due to the same phenominon of runaway avalanche in their silicate mantles."
He is using Venus as 1) an example to demonstrate that run-away subduction is possible and 2) an example of what, topographically, run-away subduction would likely look like, ie resurfacing of the earth. The problem is he is conveniently ignoring the end results (Venus is a true hell hole) and likely consequences to the earth if his model with the accelerated rates had ever occured on the earth. The heat has been discussed already, how about off gassing. Here is a little blurb that describes the effects and reactions far better than I can.
"Atmospheric gasses are thought to be the result of outgassing. Venus and the earth both have active volcanoes that pump CO2 into the atmosphere. The CO2 is removed in the earth's case by absorption in the ocean followed by reactions that turn it into beach sand and limestone. But the absorption and outgassing are temperature dependent in a complicated nonlinear fashion (words we use when we don't really know what's going on) so if the temperature increases the outgassing increases (H2O evaporates and is a greenhouse gas) and the ocean absorption decreases, the blanketing further raises the temperature and A very bad thing happens if the situation gets to the point that the planet's water trap (the altitude at which water freezes and cannot easily go higher) rises to an altitude where the sun's ultraviolet radiation can dissociate the H2O into H2 and O. The H2 will be lost in space and the O2 will eventually combine in the surface rocks so the water is destroyed forever. This process is not reversible so the planet is doomed. Just like Venus."
http://www.physics.uq.edu.au/.../ross/ph226/planet/venus.htm
Now, as we do not see the after effects of run-away subduction here on earth (the only high level of sulfuric acid near me is in a bottle in my lab, or in the battery of my car) I have to consider the possibility that it occured here on earth to be highly unlikely. This is one of the main reasons that I consider Dr. Baumgardners model to be misapplied in this instance, the available data just does not bear him out.
By the way, one way around this problem would be a limited sub-duction or a subduction that stopped short. I see no real mention of this in Dr, Baumgardners paper. I find two other points in his paper of great interest, one is that he mentions the radiation of heat from the steam into space as a menas of removing heat without metioning the concurrent incerase in temperature which would occur from such a thick water vapor layer in the atmosphere, and two
"That no air-breathing life could survive such a catastrophe and that most marine life also pershed is readily believable."
OK, he is tacitly admitting here that his model is a sterilization model. Now where is his scientific evidence that ANYONE or ANYTHING could have survived. It appears to me that his model in this paper is geared towards demonstrating that God must have did it (saving Noah and the animals) soley on the insistance that, sans data, the flood occured in a manner as his model says so God MUST be around. A rather circular arguement.
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"Chance favors the prepared mind." L. Pasteur
Taz
[This message has been edited by Dr_Tazimus_maximus, 08-16-2002]