🚀 go-pugleaf

In sci.physics, BradGuth
<bradguth@gmail.com>
 wrote
on 5 May 2007 14:38:30 -0700
<1178401109.948365.86690@u30g2000hsc.googlegroups.com>:
> On May 4, 6:22 pm, Eric Gisse <jowr...@gmail.com> wrote:
>> On May 4, 1:24 am, BradGuth <bradg...@gmail.com> wrote:
>>
>> [...]
>>
>> So where did you go to graduate school?
>
> Never did.  Sorry about that.  Better luck next life.
>
> BTW in basic physics-101;  how much does our moon contribute to GW?
>
> All inclusive: 1 watt, or is it actually worth a few multi-thousand-
> terawatts?
>
> Shouldn't we know to the watt, of what our pesky moon represents?
>
> or is your wizardly planetology still taboo/nondisclosure rated?
>
> Why do you folks care?
>
> You obviously have no honest intentions of accepting anything positive
> that's off-world.
> -
> Brad Guth
>

By lucky chance the Moon's apparent size is the same as
the Sun's.  A naive model of the luminosity would suggest
that the "inlunation" would therefore be about
0.12 * (1350 W/m^2) = 162 W/m^2.

A better model would simply note that an object with
apparent magnitude -26.73 would have 1350 W/m^2 insolation,
and for every 5 units of increase of apparent magnitude the
incoming flux decreases by a factor of 100.  Therefore,
since the full Moon's apparent magnitude has been
measured at -12.6, it is almost a million times fainter.
This yields a value of about 3.01 milliWatts/m^2.  Over the
"disk viewing area" of the Earth (which is 1/4 of the
real surface area [*]), that translates into an additional
384 gigaWatts worldwide during a full moon, and about 200
gigaWatts on average during the entire lunar cycle.

(It's not 192 because of Earthshine, so I'm fudging a bit.)

What one can do about these gigaWatts, I for one do not
know.  Compared to Sol's contribution of about
1.72 * 10^17 W on the sunlit side of the Earth, a few
hundred gigawatts is negligible.

[*] if one has a sphere of a certain radius r, and a disc with the same
radius, the area of the disc is pi * r^2, and the surface area of the
sphere is 4 * pi * r^2, by elementary geometry.

-- 
#191, ewill3@earthlink.net
Windows.  When it absolutely, positively, has to crash.

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