During an eclipse of the sun, the moon moves between the earth and the sun, completely hiding the sun from view. two hours before an eclipse, the moon is not visible. then, one hour before an eclipse, the moon appears at the western edge of the sun. the moon gradually moves across the sun from west to east. the visible shape of the sun changes until only a crescent remains. at the time of the full eclipse, darkness comes. a) the moon appears at the western edge of the sun. b) the moon moves between the earth and the sun. c) the sun appears as a crescent. d) there is darkness.