Look downward on that globe, whose hither side With light from hence, though but reflected, shines; That place is Earth, the seat of Man; that light His day, which else, as the other hemisphere, Night would invade; but there the neighbouring moon (So call that opposite fair star) her aid Timely interposes, and her monthly round Still ending, still renewing, through mid Heaven, With borrowed light her countenance triform Hence fills and empties to enlighten the Earth, And in her pale dominion checks the night. That spot, to which I point, is Paradise... -- John Milton, Paradise Lost III:722-733