 At this scale, there are 437.5 years per second, 1.575 million years per hour, and 37.8 million years per day.The concept was popularized by Carl Sagan in his book "The Dragons of Eden" (1977) and on his television series "".Sagan goes on to extend the comparison in terms of surface area, explaining that if the Cosmic Calendar is scaled to the size of a football field, then "all of human history would occupy an area the size of [his] hand".