Re: "Sagan and Velikovsky" to appear in local book stores

L. Drew Davis (
25 Jan 1995 09:45:32 -0500 (Dallas Kennedy) writes:

>One item that is clear from that book is that Venus is not in thermal balance;

Been there, done that. Read your Venus book more carefully. Then,
go read the original papers. They're cited in the bibliography.
You've been listening to Ted Holden too long. There is no good evidence
that Venus is out of thermal balance. (Enter Tim Thompson...)

>But even if there were thermal balance, the greenhouse suffers from
>these flaws: (1) no adverse thermal gradient below the cloud tops;

Huh? Define "adverse" in this context.

>and (2)
>almost no water vapor.

Why is this a problem?

>(1) For the trapping of heat to occur, thermodynamics
>requires the presence of a temperature inversion to prevent the heat at the
>surface from flowing out (by diffusion or conduction).

Um, perhaps you haven't noticed, but heat can't conduct out of an
atmosphere. There's no matter close enough to which to conduct.

>There is evidently no
>significant convection in the lower atmosphere (below the cloud tops).

That would tend to imply that the surface isn't "candescent", as
Velikovsky would have it, heating the atmosphere from below, wouldn't it?

>(2) The trapping
>of IR radiation requires, for full coverage of the IR spectrum, water vapor
>in addition to CO2.

You really need to do some up to date reading. Start with de Burgh's
1973 paper. Let us know when you get up to the '80s and '90s. That Venus
book's bibliography can help you out a bit. In short, you're wrong. You
do not currently need lots of H20. In fact, whether or not you *ever*
needed H20 on Venus to develop the current atmosphere is under some debate,
though the presence of more H20 in the (distant) past is favored.

L. Drew Davis Internet:
You might very well think that; I couldn't possibly comment.