Big History places eight thresholds throughout natural history, starting with the Big Bang event and continuing to today's modern revolution. (Some include a ninth threshold in reference to the future. We've included "threshold zero." ) The eight designated thresholds serve as markers: time periods  when conditions were conducive to an increase in complexity. For that is truly one focus of Big History: how complexity arose in small pockets within a Universe that otherwise bends toward entropy, increasing states of disorder. What transpired to transform energy and simple gases into towns, villages and megacities inhabited by creatures possessed of unfathomably intricate minds.

Today and tomorrow we introduce and provide cursory explanations of each threshold. Throughout the course, we'll delve into each threshold in much greater detail.

We begin before the beginning: with threshold zero.*

The frustration one experiences when studying origins is the notion of first causes. Whether it be the emergence of Gaia, Tartarus and Eros from the primordial chaos, the marriage of the Maori Rangi and Papa, whose couplings precipitated the world's creation, or even the Big Bang Theory, itself, each scenario prompts the nagging question: what preceded that which drew creation, itself, into existence? Even though Stephen Hawking once remarked that asking "what occurred before the Big Bang" was akin to asking what exists one degree north of the North Pole, many cosmologists today regard the concept of existence preceding the Big Bang quite seriously. This concept pertains to the multiverse," a vast array of distinct universes arising bubble-like from a space-time foam.*

According to the multiverse theory, the event we regard as the "Big Bang" coincided with the emergence of our universe arising out of some unknown -or, more likely, unknowable- field. Each universe is distinctive in character and governed by its own physical laws. In only a few, perhaps, are conditions conducive to life's development. Ours is one such Universe. The fundamental physical forces -gravitation, electromagnetism, the strong and weak nuclear forces- differ in both relative strength and range. For instance, even though gravitation is of infinite range, it is the weakest of them all. Were it even slightly stronger, the Universe would have imploded back in on itself soon after its birth. Had it been slightly weaker, the matter within the cosmos wouldn't have coalesced to form stars and planets, both essential for life. We're here discussing the Universe because it permitted us to evolve to this point. The fundamental forces were just exactly right: the first "goldilocks condition." Millions, if not billions, of alternate Universes might be fleeting in their duration or utterly lifeless.

Yet, again, however, we are confronted with the mystery of first causes. If ours is a Universe that arose from such a "foam," from what did that "foam" arise? Moreover, what would have produced that which produced the foam? One can see that these inquiries could quickly ensnare us in an infinite regress with no starting point: a column consisting of an indeterminate number of tortoises.

Threshold Zero serves simply as an acknowledgement of what might have preceded the genesis event we've dubbed "the Big Bang." However, much like the deist God that creates and then abandons, this threshold, if it exists at all, does so well beyond our bounds, hence the designation of zero. The course will focus on all the subsequent thresholds, those which are knowable to us.

So, we give a passing nod to Threshold Zero and then go on our way.

The very beginning, at least of our Universe. Current estimates pinpoint the birth of the cosmos to 13.84 billion years ago. Although physical models do not enable us to describe the precise first moment, cosmologists have developed a thorough timeline from the first knowable moment (0.00000000000000000000000000000000000000001 second after the Big Bang) throughout the various stages of the Universe's inception. The Big Bang and the events immediately subsequent to it define threshold one.

Approximately 100 million years elapsed between the Big Bang and the formation of the first stars, known as Population III. In this metal-poor infant Universe, this first generation of stars consisted almost entirely of hydrogen and helium, the two simplest elements. The clusters consisting of these stars eventually coalesced to produce vast amalgamations of stars called galaxies. Though known colloquially as "island universes," these galaxies often collided and merged to form larger aggregates. Threshold two represents the first time larger, distinct and independent structures formed out of the vast swaths of material scattered throughout the Universe.

The first stars performed a vital role in our story in that they imparted heavier elements into their local environments. Every active star generates energy through thermonuclear fusion: the process by which lighter elements are transmuted into heavier elements. For instance, at this very moment, the Sun is fusing hydrogen into helium and in the process is transmuting some of the initial material into energy. Eventually (about five billion years from now), the Sun will exhaust its core hydrogen reserves and will proceed with helium burning: the fusion sequence resulting in the creation of carbon.

Astronomers consider all elements heavier than helium to be "metals."

Although the Sun is not sufficiently massive to produce the pressures and temperatures necessary to burn carbon, more massive stars can. In fact, highly massive stars will continue the fusion processes through carbon, oxygen, silicon, and up to iron. No star, no matter how massive, can fuse iron into any heavier elements, for such processes are endothermic, meaning that they consume more energy than they impart back into the star. Consequently, the delicate counterbalance between the star's outward energy pressure and the inward gravitational pull is violently disrupted. These stars explode as Type II supernovae. These supernovae are so prodigiously energetic they can produce all the naturally occurring elements heavier than iron. They also disperse this heavy-metal material into their surroundings.

The Population III stars served as the first element factories of the Universe. They generated many through their thermonuclear processes and then perished in explosions that both created the heaviest elements and dispersed the material throughout nearby regions, thereby chemically enriching them.


More than five billion years ago, a Population II star exploded as a Type II supernova. Some of the expelled material encountered a cool, dark nebula consisting primarily of hydrogen and helium. The incorporation of these supernova remnants into the dormant cloud precipitated a slow but inexorable collapse which, over a period of more than ten million years, formed a galactic (or open) star cluster, one member of which was the Sun. Yes, that parent star that blazes in our sky now formed about five billion years ago, along with hundreds of other stars that have long since separated from this cluster and now occupy various regions within the galaxy.

Around the Sun -and most likely around all those other stars- a disc of extraneous material took shape. From this disc the planets, asteroids and other attendant bodies slowly formed. The bodies destined to become the planets incorporated all their surrounding materials into them while in the process of establishing stable orbits. While three of these planets -Venus, Earth and Mars- move within the "habitable zone," a region where temperatures could be conducive to life's development, only on Earth did life actually take hold and evolve into an advanced state.

Coming soon, thresholds 5 - 8:





*I want to emphasize that this threshold is our own addition and is not recognized as one of the Big History thresholds as defined by Big History co-founder Dr. David Christian.

**This is an instance in which we must describe highly abstract concepts in terms with which we are already familiar. We do not intend to suggest that space-time can ever assume the consistency of foam.


Whatever else might be said of that capricious and at times tyrannical ruler, one must concede that King Tyndareus ardently loved his four children. Or, more correctly, he loved the four children who were hatched out of the two eggs his wife, Queen Leda, had produced soon after she and her husband made love by a lake. Careful readers will recall that just after their tryst, while Tyndareus was off enjoying a post-coital jaunt through a nearby forest, Leda was approached and hastily seduced by Zeus, who had assumed the form of a swan. When he returned, Tyndareus noticed his otherwise naked wife coated in feathers and promptly drew the correct conclusion. She had had relations with a god who had assumed the form of a swan. Apart from reproaching her for this infidelity, Tyndareus treated her with compassion and sympathy. He knew that she was as devoted to him as he was to her. Moreover, Tyndareus also knew that if, let's say, Aphrodite or Artemis had attempted to seduce him - while preferably not in the form of a swan- he would have found it exceedingly difficult to resist.

Despite Leda''s extramarital liaison and the subsequent arrival of two eggs, King Tyndareus quickly developed an abiding love for the four children who emerged from those eggs. From one egg, Castor and Clytemnestra; from the other, Pollux and Helen. His affection for these four is all the more remarkable considering that he understandably wondered about their paternity. Perhaps the god sired none of them or, as was more likely considering the level of Olympian potency, all of them. As they grew, however, he and Leda suspected that two of the children, Clytemnestra and Castor, were his. Both bore a resemblance to the King: Castor's was striking, whereas Clytemnestra's was more subtle. The other two, however, showed no resemblance at all. In fact, though Clytemnestra exhibited a beguiling loveliness even as a young girl, Helen's beauty was unsurpassed . She not only became the world's most beautiful woman, but many went so far as to suggest that hers was a "divine beauty."

Helen was no more his daughter than Pollux was his son. Tyndareus loved her all the same.  Yet, he was troubled. She captivated all those who beheld her and, in time, would be able to claim any man in the world as her husband. Tyndareus knew, however, that such beauty could prove quite dangerous for mortals, even those of semi-divine parentage. Goddesses, notorious for their pride, could not abide rivals from the lower order, especially those whose attributes were widely perceived as being superior to those of the Olympians. Concerned primarily about Aphrodite, Tyndareus instilled in both his daughters a sense of humility and modesty. "Be gladdened by your beauty, but do not boast of it," he often warned them. He also insisted they both pay homage to Aphrodite, in order to propitiate the often jealous and wrathful goddess. Much to Tyndaerus' gratification, Helen was not only humble about her beauty, but quite kind, though, at times, mischievous. (She loved to play pranks on her siblings, much to their chagrin.)

Even though King Tyndareus was as protective as he was loving, he was unable to shield Helen from all menaces. When Helen was only twelve years old, Theseus -yes, the same Theseus who slew the minotaur- and his cousin Pirithous abducted her and carried her off to the home of Theseus' mother Aethra. Theseus' motivation remains uncertain. Some believe that he merely wanted Helen as his wife, for he had heard of her beauty and desired her. However, it has also been suggested that he heard a prophecy declaring that Helen's abduction would precipitate the greatest war the world had ever known. The glory-seeking Theseus, who was determined that his name would be as famous as that of his cousin Heracles, might have hoped that he would start that war and thus his name would remain forever known.

One might argue that the second of these two possibilities is the more likely because Theseus did not attempt to ravish or even seduce the young Helen. Instead, he simply left her in his mother's care while he and Pirithous ventured down to the underworld. You see, these two had an agreement whereby each would assist the other in the abduction of a female. Pirithous helped Theseus to kidnap Helen and then Theseus foolishly agreed to help Pirithous to kidnap Persephone, Queen of the Underworld and wife of Hades.  Well, Hades, being a god, was well aware of their aim when the two mortals approached his palace. He welcomed them warmly into his home and invited them to sit down at his table for dinner. As soon as they sat down, however, they both forgot everything: their names, their personal histories, their quest, everything. The wily Hades had tricked them into sitting on the chair of forgetfulness where they would remain in a state of hopeless insensibility forever.*

Meanwhile, Castor and Pollux quickly rescued their sister, for they were quickly told where she had been taken. They found Helen and brought her, and Aethra back to their home. From that time onward, Aethra would serve as Helen's waiting woman. It was fortunate for Theseus that he was not present when they arrived. Although he was prodigiously strong and possessed undaunted courage, he would have been no match for the brothers Gemini. It is ironic that Theseus lived only because he was trapped in the land of the dead when Castor and Pollux saved their sister Helen.

After the remaining few years of her childhood -during which time she was kept under close watch- it came time for Helen to marry. Every single -and already married- man throughout the Hellenistic world and beyond laid siege to Tyndareus' palace in the hope of becoming Helen's husband. Soon the beleaguered king found himself surrounded by a bustling throng of desperate suitors. He was terribly worried, for he knew that by choosing one suitor, he would enrage all the others. They were all inconveniently virile, strong and well armed men, all of whom considered themselves the most appropriate choice. In other words, men who might not accept disappointment philosophically. Fortunately, one of the men present, a man named Odysseus (yes, please remember that name), approached him with a solution. "Prior to selecting Helen's future husband," Odysseus suggested,  "have each man swear a solemn oath to preserve Helen's marriage no matter to whom she is wed. Have them swear to likewise defend the marriage against anyone who attempts to disrupt it. Tell them that only those who take such a vow will be considered."

Tyndareus was both relieved and delighted. He told all the attendant men about the mandatory oath and, despite some grumblings, they all dutifully swore it. Once this long oath-taking process was completed, King Tyndareus announced that Helen would marry the Spartan King Menelaus. This king was, indeed, handsome, strong, wealthy and powerful and so Tyndareus assumed that Helen would fall in love with him in time. The other men were predictably chagrined to have been excluded but, having been oath-bound to preserve and defend the marriage, did not protest and started to withdraw.

Tyndareus did try to mollify Menelaus' brother Agamemnon by having him wed Helen's beautiful half-sister Clytemnestra. He also arranged for Odysseus to marry Penelope, the comely daughter of his brother Icarius.** Truth be told Odysseus never wanted to marry Helen, or, at least, never expected to be seriously considered. Besides, he had already fallen in love with Penelope and hoped that King Tyndareus would reward him for his helpful suggestion by arranging a marriage with the king's niece, which, of course, he did.

So, Helen married Menelaus. Clytemnestra married Agamemnon and Penelope married Odysseus. And they all lived happily.....for a while.


*Heracles rescued Theseus when he traveled to the underworld to complete his twelfth and last labor, the capture of Cerberus. Or, more accurately, Hades allowed Heracles to pull Theseus off the chair.  In so doing, much of the flesh of Theseus' backside remained attached to the chair, which is why Theseus was often known as the fellow with the small posterior. Hades would not let Heracles remove Pirithous, however, for Hades knew that he was the one who had instigated the attempted abduction of his beloved Persephone. Pirithous remains there to this day, in a state of complete forgetfulness.

**Not to be confused with Icarus, the son of Daedalus who flew upon waxen wings and ventured too close to the Sun.


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Monday, September 26, 2022
Egg to Apple - A Guide to Big History III - The Thresholds    Part I:  0 - 4