[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Greenhouse

Timothy van der Linden

> >> >You keep assuming greenhouse gasses cause global warming.  That is an
> >> >unproven theory.
> >
> >> No, I keep assuming that greenhouse gasses do keep the 
> >> heat in and I've never heard (except from you) that it 
> >> keeps the heat out or has no effect at all.
> >
> >Sorry.
> >
> >How could it keep Earth heat in without keeping some solar heat out?

> My error, it keeps MORE in than it keeps out:

That would be a neat trick.  In the daytime the bulk of energy would be
coming from the sun, so it should reflect/reemmit/whatever more of that then
from the earth sources.  At night of course it would work the other way
around.  So you'ld expect a cooling effect in the day and warming at night.

> I think I made a mistake, by using the word reflection, 
> it seems that the heat is absorbed by the atmosphere. 
> This means both solar-heat and soil-heat. Other radiation 
> is going through the atmosphere without much interaction.

Reflection is a bit simplistic, but the general effect is similar.

Oh, and most of the spectrum is effected by its passage through the
atmosphere.  visible light is the least effected.

> Let me quote the following:
> "The surface of the earth is warmer than it would be in 
> the absence of an atmosphere because it receives energy
>  from two sources: the sun and the atmosphere."

Obviously simplistic given the diffences between Earth and moon.  Lunar temps
snap between 200F degrees above zero to 200f degrees below durring the day
night cycle, and change rapidly at sunset/sunrise.  Its more corect to say
the atmosphere (and water) moderates the temperature changes dramatically.
 Since they act as heat sinks.

> >> You are saying that greenhouse gasses don't exist, or in 
> >> other words there are no gasses that have a higher 
> >> reflectivity for IR-light than for visible and UV-light.
> >
> >No, I'm saying that introducing IR reflective gas wouldn't nessisarily
> >up a planet that got most of its surface temp from outside sources.  Given
> >that a lot of IR reflective gas has been added to the atmosphere without
> >changing the temp, and no one has a coherent explanation for how it would
> >increase the temp, and the whole idea is vigorously debated, I'ld say it
> >seems like a dud theory.

> I've mislead you by saying the greenhouse gasses 
> are reflective for IR, I interpreted the word opaque by 
> reflecting. Having read more about the greenhouse effect 
> this slowly became clear to me. I hope you can see, that
> this difference makes a lot of difference in our theories.

Not really.  I didn't think eiather os us thought it worked like a mirror
(thou I suppose we could have phrased things a bit clearer).

> >Could we go back to talking about the star ship?

> Yes, if we have something to talk about. Everyone seems 
> to be awfully quiet lately...

Thats true.  Maybe even we are runing out of starship ideas.

> To end this discussion properly, I would strongly 
> recommend that you read
> the "bad greenhouse" page. (I think you didn't do that yet) 
> I (http://www.ems.psu.edu/~fraser/Bad/BadGreenhouse.html)

Ok, I'll read and comment.  I'ld recomend some books, but I've no idea whats
avalible in North Europe.