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From: peter@graffiti.UUCP (Peter da Silva)
Newsgroups: net.origins
Subject: Re: Venus and Velikovsky
Message-ID: <150@graffiti.UUCP>
Date: Sat, 31-Aug-85 12:04:46 EDT
Article-I.D.: graffiti.150
Posted: Sat Aug 31 12:04:46 1985
Date-Received: Mon, 2-Sep-85 09:34:16 EDT
References: <386@imsvax.UUCP>
Organization: The Power Elite, Houston, TX
Lines: 50

>                Assume for the moment that the 4.6 billion  year age  of the
>           solar system  which Jeffery's  favors is  correct.  Estimates for
>           surface  temperatures   for  points   on  Venus,   based  on  OUR
>           temperatures and  relative differences  between our distance from
>           the sun and Venus',  would  run  only  slightly  hotter  than for
>           equivalant points  on our  surface.  Such  was the general belief
>           amongst  scientists  until  the  sixties  and  seventies  of this
>           century.

Assuming that in both cases black-body radiation is the only effect to be
considered.

>                Consider that  Venus rotates  very slowly,  about once in 58
>           earth days or so.  If Venus' sole source of heat was the  sun, as
>           called for  by the  runaway-greenhouse theory, we would expect it
>           to be a LOT hotter on the sunlit side of  Venus than  on the dark
>           side.   Indeed,  it  would  be  perfectly  logical to expect much
>           larger temperature differentials between  day and  night on Venus
>           than on the earth.  Radio emmision analyses have never shown this
>           to be the case, however.   Writing  in  PHYSICS  TODAY,  in 1961,
>           Frank  Drake  of  the  National Radio Astronomy Observatory wrote
>           that "there is little surface temperature  difference between the
>           illuminated and  dark hemispheres  of Venus".  Further exhaustive
>           radio spectrum  analyses  which  Sagan  and  David  Morrison have
>           conducted have  failed to  turn up a shred of evidence which they
>           could use in their  anti-Velikovsky crusading.   Morrison claimed
>           to  have   discovered  "no   phase  effect  after  100  hours  of
>           observations".  

See below.

>                "Increasing the mass of  the  atmosphere  may  intensify the
>                greenhouse effect, but it must also reduce the proportion of
>                solar energy reaching the  surface, while  the total  of the
>                available energy  must be distributed over a larger mass and
>                volumn.  Indeed, if the  atmosphere of  Venus amounts  to 75
>                air masses... the  amount of  solar energy  per unit mass of
>                this atmosphere will be about .01  of that  available on the
>                earth.  Such  an atmosphere  would be strictly comparable to
>                our seas and remain stone-cold, unless the internal  heat of
>                Venus were  able to keep it at temperatures corresponding to
>                the  brightness  temperatures  derived  from  the  microwave
>                emission."  

You're forgetting that we're talking about *equilibrium* conditions. So it
takes venus a while to heat up & cool down. That explains the lack of phase
differences... after sufficient time you reach equilibriumconditions, which
may be completely different from short-term conditions. By your logic because
there is a lot more mass to a 44 gallon drum than a coffeecup, you can't boil
a 44 gallon drum (modulo conduction effects).