Star Points for July, 2007; by Curtis Roelle Scaled Timeline of the Universe Thanks to you readers I've received some positive feedback on the April and May columns that featured scale models of the solar system and the galaxy, respectively. Thank you for your responses. The goal for those columns was to familiarize the reader with the almost incomprehensible size of our universe by using familiar objects for comparison. So as far as time and space go, those took care of the space part. But what about time? Current theories of the universe give its age as billions of years. Can a scale model be made that depicts the history of the universe? Let's use a 24-hour timeline. At the starting end midnight (12:00 a.m.) represents the beginning of the universe. The following midnight - 24 hours later - represents our current place in time. Assuming that the universe is 15 billion (15,000,000,000) years old, one timeline hour represents 625 million years! Because none of us were around to see it we'll appeal to scientific theory regarding what's happened in the universe prior to human recorded history. The dominant creation theory, at the present time at least, is the "Big Bang" model. According to that theory all of the energy and matter presently in the universe came into existence instantly during an explosion in which space and time were also created. For the first two billion years the universe cooled, matter and energy decoupled, and the universe was filled with a hot soup of particles and light elements. At a little after 03:00 a.m. in our model galaxies, clusters and super clusters of galaxies had formed from the coalescing clouds of matter while leaving enormous voids in between. The earliest generations of stars had already formed and died leaving behind more complex atoms and elements. At about 05:00 a.m. on our clock the universe looked much like it does today except that the galaxies were closer together then. Three billion years had passed. As time goes on the universe continues to expand and the groups of galaxies move farther away from each other. Nothing much happens locally in our neck of the woods until about 4.7 billion years ago, or 04:29 p.m. when a cluster of stars forms, one of which becomes our sun. About 200 million years later at 04:48 p.m. the earth had formed. Only 48 minutes later at 05:36 p.m. amino acids are taking shape. Four billion years ago. Cell membranes develop leading to the formation of bacteria and algae. They figure out how to multiply by cell division and develop the process of photosynthesis. Meanwhile ever more complex forms of life are beginning to develop. A jellyfish appears around 11:00 p.m., 650 million years ago. New species of lichen, mollusks, and fish are rapidly flourishing. The insect makes its debut at 11:26 p.m., 350 million years ago. The dinosaurs' earthly rule begins at 11:36 p.m. They are joined by the birds 10 minutes (100 million years) later. By 11:54 p.m. the dinosaurs are extinct. The time is Sixty-five million years ago. The earth is populated with mammals including some primates. Homo Erectus takes a quick bow at 11:59:43 p.m. followed by Neanderthal man at 11:59:59 p.m. We will now represent the final second of the day using decimal fractions of a second. Human beings, or "people" don't appear until 11:59:59.4 p.m. The time is 100 thousand years ago. The Roman Empire begins promptly at 11:59:59.9885 p.m. Man walks on the moon at 11:59:59.9999 p.m. Well, you get the idea. The existence of humankind is limited not only in terms of space on a dust mote of a planet circling a far- flung star. In terms of time, all the people from every generation that have ever lived amounts to hardly more than the blink of an eye.