&gt;The entire sky would be about as bright, and as hot, as the surface of the Sun.<p>Not so according to “The Inverse Square Law”.[1]  If one measures the light flux through a hypothetical sphere drawn around a light source and then doubles that spheres size, the light density must decline or you&#x27;ve broken conservation of energy. [2]<p>[1] <a href="http:&#x2F;&#x2F;bccp.berkeley.edu&#x2F;o&#x2F;Academy&#x2F;workshop08&#x2F;08%20PDFs&#x2F;Inv_Square_Law.pdf" rel="nofollow">http:&#x2F;&#x2F;bccp.berkeley.edu&#x2F;o&#x2F;Academy&#x2F;workshop08&#x2F;08%20PDFs&#x2F;Inv_...</a><p>[2] <a href="http:&#x2F;&#x2F;www.compuphase.com&#x2F;electronics&#x2F;candela_lumen.htm" rel="nofollow">http:&#x2F;&#x2F;www.compuphase.com&#x2F;electronics&#x2F;candela_lumen.htm</a>