(February 10, 2016 at 10:23 am)pocaracas Wrote: I'm thinking the argument should be more about the energy and not the temperature...
If you can transfer enough energy to the combustible material, it should catch on fire...
Yes, I think it is exactly that, it's not about temperature. The color temperature of the reflected moonlight is high enough - the etendue argument wants to tell us that we cannot generate greater intensity using a lens than is present on the moon surface.
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