Message: 13 Date: Thu, 7 Apr 2005 11:15:13 +1000 From: David Vaughan <[EMAIL PROTECTED]> Subject: Re: Ann: Greenhouse effect on Venus To: use-revolution@lists.runrev.com Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset=US-ASCII; format=flowed
> snip
Jim,
So why is Mars colder than a blackbody planet in its orbit position? Just curious.
thanks David
David,
Because Mars is not black, it will absorb only some on the incident solar radiation and reflect it reflects the rest, while the Black Body planet absorbs all of the solar radiation and so is hotter. (This assumes that Mars does no trapping.)
The tricky thing to understand is why Venus, which only absorbs some of the solar radiation, is hotter than a black body which absorbs all of the solar radiation.
The answer is that a good absorber is also a good radiator. The black body absorbs more heat from the Sun than Venus, but it also radiates more of it energy than Venus. Venus is not as good an absorber, but it is also a poor radiator because it *traps* the solar radiation through the greenhouse effect and that energy which is trapped is not radiated.
Hope this explains it.
Jim _______________________________________________ use-revolution mailing list use-revolution@lists.runrev.com http://lists.runrev.com/mailman/listinfo/use-revolution
