note hawking's preposition it's to not by also note that the on earth seems to be your personal interpretation it's really quite hard to heat anything to k on earth because you won't find anything that needs heating also note that your or hawking's math is a bit off c is only k since the cmb is roughly k it would heat a pizza in otherwise empty space to c unless my math is off which is a very real possibility at any time but especially when i lecture about other peoples shortcomings