Timeline, Part Two

[stickmaker]

Second part of a timeline I created as part of the background for some science fiction stories I'm writing.

Timeline

Part Two

 

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7.1 BYBP The microwave background cools below 5 K.

The Demmit S'Tee reach the end of a slow retrenchment from interstellar society. They withdraw to a handful of worlds and soon begin fading away. Within a hundred thousand years they will be extinct. 

Through the next few hundred million years all the other senior species in the Local Great Cluster follow the Demmit S'Tee to extinction. A few of the younger species move into some of the niches thus emptied, many repeatedly jumping tens of thousands of years in technological development by scavenging equipment and information left by their predecessors. Major wars are fought over these scraps, and some otherwise promising civilizations die, through violence or exhaustion, because of the conflicts. None manage to equal the departed societies. 

7 BYBP Growth of large galaxies slows. 

6.8 BYBP Alpha Centauri forms. 

The Shebreel become the dominant culture in the Local Great Cluster. Though their tools are advanced and their domain vast by current standards, they are, for their time, unremarkable. Moreover, much of their technological competence is derived from skillful scavenging and careful analysis of recovered artifacts and databases left by previous cultures. Once established, they do little with their realm besides slowly enlarge and consolidate it. This cultural inertia results in their rule lasting less than four million years. They are eventually conquered, and their conquerors conquered not long after, in a pattern which lasts nearly half a billion years. Eventually one culture - the Aubottle - manages to acquire and retain power for a period approaching that of some of the earlier Great Societies, but they also do little with it except maintain the status quo. Finally they, too, fade away as newer, more aggressive species develop first starflight then rapidly expanding domains.

Over the next billion years several major starfaring species rise, become dominant, then slowly fade or quickly die. None manage to equal the Demmit S'Tee in technological development or endurance or even breadth of physical extent controlled. Indeed, the trend is for each dominant culture to be less sophisticated and technologically advanced than its predecessor while controlling a smaller volume of space. Even the Aubottle were a shadow of the Shebreel. Finally, there is no culture left capable of managing all of even one large galaxy.

6.5 BYBP The Milky Way begins spiralizing.

5.8 BYBP The Second Quiet Interval begins. No technologically or socially significant species arises for most of a billion years.

5.75 BYBP A supernova enriches a dense molecular cloud and greatly speeds its collapse. This eventually results in the formation of Sol System. 

5.5 BYBP The Solar nebula starts collapsing.

~5 BYBP The cosmic expansion rate increases.

4.9 BYBP The Second Quiet Interval ends with the emergence of an alliance of four young starfaring species (the Aeurl, the Ebletg, the Loren and the Nolek) which developed relatively closely together at nearly the same time. The Four-Part Alliance divides first their home galaxy, then the entire Local Great Cluster evenly between themselves. Forays are made into other Great Clusters for the first time since the prime era of the Shebreel, but these are extensive exploration missions rather than assimilation or colonization projects. All such efforts which survive return, leaving no long-term settlements. The universe has grown larger, and the distance is simply too great for the technology available to allow practical conquest or commerce.

At their height, the technology of the Four-Part Alliance will come close to that of the Shebreel, actually exceeding it in a few specialized applications.

4.85 BYBP Proxima Centauri forms. 

4.62 BYBP A low mass supernova disturbs the cloud of gas and dust which is already collapsing to form the solar system. The resulting impulse shapes the proto-Sun and surrounding disc where the planets coalesce. 

4.59 BYBP A star slightly smaller than Sol flies by at about 90AU distance from it, significantly reshaping the nascent stellar system. What becomes known as the Solar System begins to achieve a distinctive form. 

4.57 BYBP The Sun begins fusion.

4.54 BYBP The proto-Earth forms. 

4.53 BYBP The proto-Earth is struck by a body later named Theia. The collision destroys the far smaller Theia and severely alters the early Earth, forming a synestia. Additional - though smaller - collisions drive more of the proto-Earth's crust into space, increasing the mass in the orbiting ring. Much of Theia and parts of the proto-Earth's crust eventually coalesce to form the Moon. The heat released drives off a significant portion of the lighter volatiles from both bodies, preventing the Earth from developing a dense, Venus-like atmosphere. Chemical reactions with much of the remaining water and that brought by comets further reduce the carbon dioxide content. 

This is part of a major disturbance of the non-stellar bodies of the system, in what will later be named the Grand Tack. The largest bodies formed first, with Jupiter ahead of all the others after the Sun, forming about 3.5 AU out. Drag from the gas and dust around the Sun caused the massive gas giant to move inward, to about 1.5 AU. This movement inwards quickly (on a stellar scale) stopped, due to a resonance with Saturn. A tidal effect from other bodies - including the dense disc of gas and dust closer to the Sun - then caused the pair to spiral back outward. This cleared most of the smaller items from the inner Solar system, reduced the size of the forming Mars, created the asteroid belt, the Kuiper belt and the Oort cloud and pushed the other gas giants outward. 

These events are studied and recorded by several extant starfaring civilizations. They are noteworthy due to the number of unusual occurrences, but the individual events themselves are common during stellar system formation. Apparently, no-one notices that Theia brought with it a large chronostasis waveform containing Chronometric Research Station #2453. Since the stasis bubble has a low density compared to most of the other materials which make up either colliding body, the Station gets sprayed out with the lighter debris. This ring of rock soon consolidates into the Moon. 

At roughly the same time, a similar massive impact forms the Borealis Basin on Mars. 

4.51 BYBP The Earth's Moon forms as a distinct body. Chronometric Research Station #2453 is incorporated in this.

4.48 BYBP An orbital resonance with Jupiter and Saturn shifts the orbits of Uranus and Neptune further away from the Sun while completely ejecting a similar small gas giant and several rocky bodies of various sizes. This disrupts asteroids and comets and eventually causes the Late Heavy Bombardment in Sol System. The planets are gradually assuming their current orbits through gravitational resonance.

4.4 BYBP The first oceans form on Earth. The oldest surviving minerals begin to form.

4.2 BYBP Earliest signs of magnetic field on Earth. Earliest signs of thick crust on Earth. Earliest potential signs of life on Earth. 

4.11 BYBP Late Heavy Bombardment begins. 

4 BYBP Hellas impact basin forms on the Moon. South Pole-Aitken basin forms on Moon. This last remains the largest surviving impact crater in the Solar System. 

Evidence of first large above-water land masses on Earth. 

3.9 BYBP The last universal common ancestor — LUCA for short - appears on Earth. There is speculation later by humans that the earliest living things on Earth developed from extraterrestrial spores brought by earlier impacts.

Imbrium Basin formed on the Moon by a 250 kilometer impactor. 

3.8 BYBP On the Moon, Tyrrhena Mons and other volcanoes in the highlands near Hellas begin to erupt. 

Late Heavy Bombardment in Sol System tapers off sharply, but continues at a low level for almost two billion more years.

On Earth, the oldest known band of iron oxide forms. 

3.7 BYBP The Oceanus Procellarum is formed on the Moon from a combination of continuing volcanic activity and a cluster of asteroid strikes. 

The Tharsis Bulge begins to form on Mars. Beginning of the Hesperian Era.

Oldest known soil on Earth formed. Earth's magnetic field begins to stabilize. 

3.6 BYBP The Lullusk become a starfaring species.

Valbaara supercontinent forms on Earth. First signs of photosynthesis.

The Meridiani region of Mars holds the last large body of water on the planet.

Gale crater formed on Mars by impact. 

3.5 BYBP The Four-Part Alliance begins to break down from a combination of sheer age and the stresses which come from the emergence of younger, more aggressive cultures in several parts of their combined empire. Due to these pressures the Alliance splits into two coalitions which blame each other for their shared troubles. Over the next several million years the four members switch allegiances - among themselves and with other species - repeatedly, but no-one ever manages to achieve a significantly dominant position to overpower the others. 

The situation becomes even more chaotic when local subgroups of the four still - if barely - dominant starfaring cultures begin making their own agreements, ignoring their supposed leaders. Eventually, the civilization ruled by the Four-Part Alliance dissolves into thousands of squabbling local entities, many commanding the resources of only a few hundred star systems. These continue to bleed each other to a slow death for another ten million years. However, with the remnants of technology they possess even these paltry remnants are capable of exterminating newly arisen starfaring cultures, many of which are only a few thousand years old when they encounter these failing splinters.

Eventually all these fragments of old glories fade away, mostly through losing the understanding of the tools of their ancestors. A huge portion of the Known Universe is left bereft of any civilization larger than tiny enclaves of no more than a few thousand star systems.

Oxygen on Earth rises to a peak. Other chemical signs left in rocks from that period strongly imply an already developed ecosystem. A 25 kilometer asteroid strikes what will later become northwest Australia. 

Atmospheric pressure on Mars is already under a quarter what it is on modern Earth. The evaporation of the planet's water is well underway.

3.48 BYBP Rocks with oldest known physical signs of life on Earth form in what would later become Australia. They and other fossils from that era show life forms which are developed enough and plentiful enough to imply that life has already been thriving on the planet for a good interval by this time.

3.4 BYBP The Known Universe enters The Third Quiet Interval. During this time the balance between dark matter and Dark Force shifts towards the latter, and the expansion of the universe begins to accelerate. What effect this might have on such a relatively minor and short-term phenomenon as civilization in something as small as the Local Great Cluster is uncertain.

Massive impacts on Mars trigger significant hydrologic events. 

3.3 BYBP End of the Hesperian Era on Mars. The air and seas are fading.