Another essay for the middle of the night. This is a chapter from my book The Emergence and Nature of Human History, Volume One. (I have published this on DKos before, in a slightly different version.)
It’s difficult to find the exact boundary between the Australopithecines, the genus of upright animals thought to be ancestral to the genus Homo, and the first true humans. But if we assume something like Homo habilis is the first truly distinct member of our genus, we must try to picture the life of these earliest humans on the African savanna some 2 million to 2.5 million years ago. How dauntingly huge the world must have seemed to them! Probably moving in nomadic groups, the earliest of our kind gathered food from an environment over which protracted walking was required. Who knows the true range of their wanderings? They trudged across the surface of their apparently huge home at ordinary walking speed, perhaps 3-4 miles per hour. (Even running as fast as they could, were they able to reach anything like sapiens running speeds, perhaps 27-28 miles per hour in short bursts?) Their world must have appeared to be endless, if the exertion required to traverse its surface was any indication. (Of course, if they possessed any concept of the totality of the world, they probably saw the area of their own migration as its full extent.) A more advanced type of human (either a descendant of habilis, or an entirely independent offshoot from a common ancestor, depending on the hypothesis accepted) known as erectus, began the human diaspora out of Africa, perhaps as early as 1.5 million years ago. (It is now thought that erectus did not survive as a going concern in Asia, and that a later African sapiens group became the progenitors of modern humanity.) Their migration may simply have been a matter of moving base camp a few hundred or a few thousand feet a year, depending on the circumstances, or it may have been a migration punctuated by long journeys stimulated by desperation or unusual conditions.
But whatever the actual timetable of a particular group’s journey, the expansion ultimately took on a truly epic nature. Think of what physical barriers these travelers must have encountered. We have no written record of their experiences, but their travels must have been characterized by long periods of dull, seemingly endless plodding punctuated by huge challenges and harrowing dangers. And these dangers were not being met by humans of great size and tremendous strength. The height of the average member of the genus Homo, as we will examine in greater detail elsewhere, has averaged somewhere around five feet (about 1.5 meters), with males generally taller than females. A small mountain of 300-400 meters in height would be formidable to such a being; a mountain in the Alps would be huge; and a mountain in the Himalayas would seem unspeakably gigantic. Our ancestors roaming the eastern hemisphere encountered such giants, and surely must have felt dwarfed by them.
In these encounters with the world, undoubtedly many travelers lost their lives along the way. And among the survivors, an idea was deeply impressed upon their consciousnesses: the world is enormous.
As Homo sapiens evolved, spread, and founded a wide variety of new cultures, each group undoubtedly had its own conception of the world’s extent, again, a conception generally limited to the area in which their tribal hunter-gatherer group roamed. Once larger numbers of permanent settlements than had existed in the pre-agricultural world had been founded, and literacy became commonplace, humans (or at least that minority which was educated) began to gain some understanding of the actual geography of the region where their group lived. Until recent centuries, such knowledge was sketchy and speculative at best. When humans began venturing out on epic sea journeys, from the Phoenicians in the early 12th century BCE to the Chinese and Western Europeans beginning in the fifteenth century CE, the sense of the Earth’s hugeness was reinforced, as was the impression of the difficulty in crossing the Earth’s surface. (It was not unusual, for example, for a pilgrimage from the German states to Jerusalem to take the better part of a year, owing to a variety of difficulties.)
Regarding the size of the Universe, the height of the heavens themselves, our ancestors had no real conception. In early Mesopotamia, those who stood at the top of ziggurats were thought to be appreciably closer to the stars. Archimedes, perhaps the most brilliant mind of the Greco-Roman Classical era, calculated that the Universe was, in our terms, about 12 trillion miles in diameter—what we would call 2 light years. And with the notable exception of Aristarchus of Samos, most educated people believed that the cosmos rotated around us. Aristotle built his cosmology on this assumption. The great astronomer Ptolemy deeply influenced both the Hellenistic Greek world and later the educated Arabic-speaking world through his epic work, and both official Christianity and Islam assumed its absolute accuracy.
But there were observations that troubled many adherents of geocentrism. The orbits of planets, particularly Mars, seemed “eccentric”. A weird, elaborate system of “epicycles” was invented to try to clear up the growing numbers of observations that could not be made to fit into an Earth-centered Universe.
Beginning with the work of Copernicus in the 16th century CE, the picture of a geocentric cosmos began to be superseded by a new conception of the heavens. As astronomers began to broaden the scope of their investigations in the centuries that followed, facilitated by new and more powerful technologies, the size of the physical Universe seemed to “grow”.
In the last century or so a revolution has taken place in the human understanding of our planet’s physical relationship to the Universe. Between 1917 and 1932 the most massive expansion of our conception of the Universe’s size that has yet taken place occurred. With the discovery during this period that the Universe was expanding, that it contained enormous numbers of other galaxies, and was very, very old (from the human perspective), all of our previous conceptions of the cosmic order were systematically overthrown. And with the overthrow of our conceptions of the Universe came another, unexpected result, one which many people have yet to confront: the overthrow of the centrality of the human race in physical reality. This development is momentous, perhaps as momentous as anything humans have ever discovered about the world, and yet its full impact has yet to be felt.
Our small size in relation to the Earth turned out to be deceptive; it didn't give us a picture of our world’s true place. In the larger context of the physical universe, the Earth is almost unimaginably miniscule.
We can begin by considering the Earth in relation to objects in our own solar system. The Earth, large as it is to us, is tiny compared to Jupiter, which has a volume more than 1,300 times that of our planet. (The perpetual storm in Jupiter’s atmosphere, the Great Red Spot, is in itself three times the surface area of the Earth.) The size of our neighborhood star, the Sun, is even more overwhelming. The Sun, some 864,000 miles in diameter could hold our entire planet over 1,300,000 times. A single arc of gas erupting from the Sun’s surface would utterly engulf our planet were it within range of us. The diameter of the planetary orbits in the Solar System our Sun rules over (counting the dwarf planet Pluto) is more than 7.5 billion miles as compared to around 7,900 miles for our little world—a ratio of more than 949,000:1. But that’s just the start of the measure of our cosmic insignificance.
The Sun is merely a star of average size. There are, not terribly far from us in the Galaxy (relatively speaking), many stars of such immensity that they dwarf our Sun. Alnilam is 27,000,000 miles in diameter, capable of holding our Sun 30,500 times and the Earth almost 39.7 billion times. Menkar, a red giant, is 48,000,000 miles in diameter, more than 170,000 times the volume of our Sun and 221 billion times the volume of the Earth. Betelgeuse, a dying supergiant, is 433,000,000 miles in diameter, some 125 million times the volume of our Sun and more than 1.6 trillion times the volume of the Earth. And VY Canis Majoris, the largest star in the Milky Way, has a diameter that on the low end is estimated at 1,600,000,000 miles, making it more than 6.3 billion times more voluminous than the Sun and 8.3 quadrillion (8.3 x 10^15) times the volume of the Earth.
Astronomical distances and dimensions are so gigantic that they are usually measured in light years (or parsecs, which are about 3.26 light years). A light year is the distance light, the fastest known thing, travels in a vacuum in one Earth year—a distance of 5,878,499,810,000 miles. The Milky Way Galaxy, in which our Sun is so ordinary, measures anywhere from 100,000 to 120,000 light years in diameter. Therefore, the Milky Way is (to be on the low end of the estimate) 100,000 x 5.878499 trillion miles across—about 588 quadrillion miles. This is more than 74 trillion (7.4 x 10^13) times the diameter of the Earth. The galaxy contains anywhere from 100 billion to 400 billion stars, depending on the number of dwarf stars that may exist. (Incidentally, astronomers locate our solar system in a partial spiral arm of the Milky Way Galaxy known as the Orion Spur. We are 26,000-30,000 light years from the galaxy’s center). On such a scale, our planet’s size is already negligible. But the picture gets worse.
It was not understood until the 1920s, through the brilliant work of Edwin Hubble, that the Milky Way Galaxy was far from being the only one in existence. Since Hubble’s time, we have vastly improved our observational tools, including the orbiting of space telescopes (the first one named in Hubble’s honor, fittingly enough). And the story they tell humbles us even more. There are whole clusters and walls of galaxies, all held together by gravity. NASA recently estimated that there were 125 billion galaxies, and emphasized that infrared cameras, radio telescopes, and x-ray cameras might greatly increase the estimate. Most estimates run from 100 billion to 200 billion total galaxies.
The distances between us and the closest full-fledged galaxies are staggering. One of the nearest galaxies, the Sagittarius Dwarf Elliptical Galaxy, is 75,000 light years away. This means a beam of light that started traveling from our galaxy at a speed of over 670,000,000 miles per hour 75,000 years ago, before any humans were in the Americas, is just arriving at Sagittarius now. The Small Magellanic Cloud, another “close” neighbor, is 210,000 light-years away. A beam of light that started from our galaxy to the SMC at about the time that modern Homo sapiens were first evolving is just arriving there now. And the nearest spiral galaxy to us, Andromeda, is so far away that a beam of light that left our galaxy when humans were no more than a handful of Homo habilis types living in eastern Africa 2,000,000 years ago, is just arriving there now.
Other galaxies are not just tremendously distant. Some of the galaxies in our Universe are mind-bogglingly huge as well. In 1990, Science News announced the following:
By carefully recording the faint light surrounding a bright galaxy at the center of a dense cluster, a team of astronomers has uncovered evidence for perhaps the largest and most luminous galaxy known. This gigantic agglomeration of stars, which sits at the center of a rich galaxy cluster called Abell 2029, extends 6 million light-years in diameter (more than 60 times the width of the Milky Way) and emits more than a quarter of all the light produced by the entire cluster.Such an object has a diameter 4.7 billion times the diameter of our Solar System’s planetary orbits. This would be as if our solar system were eight one-hundredths of an inch across and the giant galaxy in question were roughly the diameter of North America from the Arctic Circle to Colombia. By my calculations, this enormous galaxy in Abell 2029, if seen as a circle, would be more than 22 quintillion (2.2 x 10^19) times the area of a circle represented by our solar system.
And when the Earth is finally compared to the entire physical Universe, the human species all but vanishes completely. The Earth’s polar diameter of about 7,900 miles must be compared to the estimated 156 billion light years diameter of the Universe. (We should recall that space can expand faster than the speed of light.) The number of miles represented by a light year, multiplied by 156,000,000,000 yields a staggering result: the estimated Universe is, compared to the Earth’s diameter of 7,900 miles, more than 116 quintillion, or to be precise, 116,081,768,400,000,000,000 (1.16081768400000000000 x 10^20) times larger in diameter.
Atoms range in size from 1 x 10^-10 to 5 x 10^-10 of a meter in diameter. The Earth is 1.2713 x 10^7 meters in diameter at the poles. Therefore, the Earth is about 127.13 quadrillion times (1.2713 x 10^17) the diameter of the smallest atom. In other words, the Earth is smaller in relationship to the Universe than the smallest atom is in relation to the Earth by a factor of about 1,000.
The creation myth believed until recently by most humans in the Western world seemed to posit a Universe no more than a few thousand years old. Interpreters of the Book of Genesis, for example, have often come up with a figure of 6,000 years for the age of the cosmos, with humans appearing within the first week of the Universe’s existence. Christian, Jewish, and Muslim fundamentalists generally agree with this assessment.
In The Kojiki, which includes the Japanese creation story, the age of the Universe is said to be at least “millions and millions” of years, although the ancient Japanese had nothing but supposition on which to rest this estimate. In Chinese mythology, one source puts the age of the Universe at 18,000 years. Hindu cosmologists speak in terms of enormous time periods. One Hindu belief asserts that the Universe is more than 314 trillion years old, for example. But all of the enormous time periods postulated in Hinduism are specifically linked to the age of the various manifestations of God, and in all Hindu hypotheses about the creation of the Universe, humans are present right from the start. We must assume, additionally, that the Hindu estimates, like those of the Japanese, are based on supposition and imagination, and not on any empirically-based observations.
All cultures have creation myths, but they seem to share one common theme: humans are of greater or lesser importance in them, but one of the central purposes of the act of creation by God or the gods or the infinite, if not the central purpose, is the creation of humans, and humans appear either immediately at the beginning of the Universe or not terribly long after it comes into being. All creation myths share another commonality, as well: they have all been shredded to pieces and superseded by the discoveries of modern science.
Recent findings from the Wilkinson Microwave Anisotropy Probe (WMAP) space project indicate a universe 13,700,000,000 years old. The earliest (possible) member of the genus Homo, Homo habilis, is thought to have emerged no earlier than 2,500,000 years ago. Even with the discovery of a find called Toumaï' (not a member of Homo) in Chad, we can say that the hominid line emerged no earlier than 7,000,000 years ago. Therefore, the genus Homo has occupied approximately less than two one-hundredths of one per cent of the total existence of the Universe (more precisely about .01825% of the Universe’s age). To use a slight variation on how Carl Sagan once put it, if the entire age of the Universe could be reduced to one year, the genus Homo did not emerge until around 10:30 pm on 31 December. In this scale, the oldest member of sapiens, perhaps 200,000 years old, emerged at about 11:52 pm on that fateful last day. The earliest agriculture in the Fertile Crescent, about 11,000 years before the present, began about 25 seconds ago, the earliest written records, about 5,000 years old, emerged about 11 seconds ago, and all of human history since the year 1500 has, in this Universe shrunken temporally to one year, taken place over the last 1.15 seconds. The life span of a centenarian on this scale is reduced, therefore, to about one-fifth of a second. The life span of a person of typical life expectancy in the advanced countries would be about one-seventh of a second.
Some people might prefer to think of these issues by picturing an enormous timeline. So let’s consider this. Let’s say you have a timeline that stretches out 1,000,000 meters in length—1000 kilometers, or about 621.3 miles. Each year since the Big Bang would be about 0.07299 millimeters on such a scale. On this scale, we would have to travel 664,293 meters—almost two-thirds of the total length of the line—to reach the beginning of the Earth. We would have to travel almost 999,818 meters on that timeline to reach the first member of the genus Homo. We would have to travel 999,985 meters to reach the first sapiens, 999,999.2 meters to reach the earliest civilization, and 999,999.6 meters to reach the earliest writing. The last 500 years of human history would take up about the last 36.495 millimeters of the timeline, more than 999,999.96 meters from the start, the lifetime of a centenarian would be 7.299 millimeters from the end of our one million meter line, and the lifespan of a typical human in the advanced nations (about 75 years) would take us less than 5.5 millimeters from the end of a line 1,000,000 meters in length.
We are an amazingly recent occurrence in this iteration of the Universe. Even in comparison to the Earth, a mere 4.6 billion years in age, we are insignificant. Imagine if the Earth were a sentient, conscious being. Further imagine that it had the powers of observation and evaluation. Can you imagine how fleeting the life of a seventy year old person would be to such a being, a being almost 66,000,000 times older? It would be as if our 70 year-old simply evanesced out of nowhere and disappeared almost instantaneously. The rhythms of the Earth are unimaginably slow in comparison to the frantic pace of our lives. The Earth’s memory would include geologic eras measured in tens or hundreds of millions of years. It would contain the earliest glimmerings of life, the upheavals and splitting apart of whole continents, the births, lives, and deaths of countless entire species. The recession of the last ice age, some 14,000 years ago, would be a recent memory, comparatively speaking, to such a being. It would be the equivalent of a memory our 70 year-old would have of something that happened 45 minutes ago!
We are newborns; we are very, very young children of space-time and energy-matter. We were not created at the start; we were not created near the start; we weren’t even created near the middle. We are the latecomers. It took eons of time to produce us, and our reign on this tiny world has been vanishingly brief. We have only just begun our journey, and there is no guarantee that it will last much longer than it already has.
So what does this all mean? It means that all human-centered views of the Universe are nonsense, utterly indefensible on every level. It means that our myths were simply quaint efforts to explain reality, based on the superstitions and limited observations of the ancient world. These myths perhaps possess some literary or historical value, but they possess no scientific value whatsoever. Our utter physical and temporal insignificance call into question all anthropocentric views of the Universe’s origin and various physical features. To contend that the Universe was created for the benefit of a set of beings who occupy a world as ludicrously small as ours, is to stretch credulity to the breaking point. We thought we were the center of creation. We’re not. We thought the object of the Universe’s existence was to produce us. In all probability, it wasn't. Perhaps, in an unspoken way, we thought if our world disappeared it would matter to the Universe, or at least be noticed. It wouldn't. Most humans, even though they know that the Earth is very small and that humanity is very young, still tend to embrace some variation of the view that everything was made for us. It is time, in my humble opinion, for us to disabuse ourselves of this notion. The individual human life is virtually nothing in the scale and age of the Universe in which it evolved. This is a hard truth from which we can no longer turn, and it carries implications that must be confronted if any kind of human dignity and worth are to be salvaged from the wreckage of our broken dreams and shattered mythologies.