(February 10, 2016 at 9:44 pm)Anomalocaris Wrote:(February 10, 2016 at 9:31 pm)Alex K Wrote: I mentioned the light temperature.thing in detail above, I think the crucial difference if you replace the moon by a mirror is that the mirror would preserve the etendue of the sunlight whereas a scattering surface greatly increases it, and so we lose the ability to concentrate great amounts of intensity by just using an idealized lens.
Yes, but shouldn't the etendue just of the black body radiation, not even the reflected light, of the day side of the moon be enough to to set many things on fair if only oxygen is available?
The surface temperature in the daylight side of the moon is about 140C. Even if the moon is perfectly black and reflected nothing, it's own black body radiation ought to be able to heat an object otherwise unable to shed heat to the same temperature as itself. Many things can catch fire at 140C.
Good point, In that case one would think that yes, both should be sufficient to light something very flammable with a very large lens.
The fool hath said in his heart, There is a God. They are corrupt, they have done abominable works, there is none that doeth good.
Psalm 14, KJV revised edition
