In article <408719ff$1@news.povray.org>,
 Dan P <dan### [at] yahoocom> wrote:

> What you are describing is called the "albedo" of an object. This 
> website[1] defines albedo as, "the fraction of light that is reflected 
> by a body or surface." This site contains some albedos that illustrate 
> your point:

Yes, I know. I mentioned this in some of the messages I posted 
previously. Such as the one a couple steps up this thread posted in 
response to one of your messages. Which you replied to. It'd help if you 
read them first...

The Moon's albedo varies drastically with angle because of glass beads 
in the regolith (surface debris formed by impacting bodies...lunar dirt, 
basically) which tend to reflect light back in the direction it came 
from. The apparent albedo from earth is usually closer to 7%, but it 
reaches about 12% at full moon. It'd be interesting to simulate this in 
POV...


> The Earth is 21% brighter than the moon (as you've said), probably 
> because of all the water on the surface and in the clouds. Venus is 43% 
> brighter because it has a lot more clouds to reflect the light. Venus 
> has been so bright to us that people have mistaken it for the light of 
> an on-coming train!

Venus is also closer to the Sun, about 0.7 AU, which means it intercepts 
twice as much sunlight. Approximating the Sun as a point source. ;-)
Still, I think you'd have to be pretty confused to mistake it for a 
train light.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/

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