Anciska (A.K.A RS 8509-2-6-186927-250 5.1) is the only large moon of Planus, a gas giant orbiting an orange dwarf star system in the Fornax Galaxy. It was the homeworld of the Tatzens.
The parent orange dwarf star ignited some 7.1 billion years ago. Anciska began forming some 7 billion years ago around Planus, which had itself formed about 30 million years earlier. By 6.9 billion years ago, it had coalesced into roughly its current size. 6.7 billion years ago, a deserted alien spacecraft entered the system and got drawn into an elliptical orbit around Planus. After circling the gas giant for centuries, it crashed into Anciska, seeding it with extraterrestrial bacteria. What happened next is listed below. The Tatzens used a calendar system in which they set 2,583,991,627 BCE as their year 1, which was when they first began exploring space.
6.5 Billion BCE: Oceans have formed. Eukaryotes have evolved.
6.1 Billion BCE: Oxygen and carbon are filling the air.
5.2 Billion BCE: The first photosynthetic organisms have developed.
4.5 Billion BCE: Stromatolites appear; the first visible life.
3.9 Billion BCE: The first sea plants appear.
3.3 Billion BCE: Colonies of small, meter-sized plants spread to land.
3.1 Billion BCE: Pentapods are the first land creatures.
2.9 Billion BCE: Forests of hundred meter tall plants sprout across land.
2.8 Billion BCE: Asteroid impact causes the extinction of 78% of life.
2.7 Billion BCE: Increase in terrestrial life diversity.
2.65 Billion BCE: First flying creatures.
2.59 Billion BCE: A volcanic eruption wipes out several large predators.
2.586 Billion BCE: In the absence of being prey, the Tatzens flourish.
2.584 Billion BCE: The Tatzens smelt metals and grow crops.
2,583,994,000 BCE: Cities grow rapidly. Irrigation is implemented.
2,583,992,000 BCE: Text is printed. Modern sewage systems come into use.
2,583,991,700 BCE: Aircraft fly. The world is fully mapped. Increase in international trade.
2,583,991,663 BCE: Global conflict. Surface-to-air missiles are put into use.
2,583,991,648 BCE: Global war ends. Radar is used for aircraft. First modern computers.
2,583,991,627 BCE: First satellites launched; images of Anciska from space taken.
2,583,991,621 BCE: First rotating space station constructed. Space tourism begins in earnest.
2,583,991,616 BCE: Population reaches 1 billion. First missions to Planus.
2,583,991,597 BCE: First missions to the outer planets. Floating cities constructed around Planus' atmosphere.
2,583,991,592 BCE: First interstellar colonization efforts.
2,583,991,574 BCE: Dyson sphere begins construction.
2,583,991,565 BCE: Interstellar war breaks out between Anciska and its four exoplanet colonies.
2,583,991,453 BCE: Both sides are nearly obliterated and civilization falls into permanent decline.
2,583,991,388 BCE: The last Tatzen goes extinct, but their dyson sphere still sits filled with Anciskan life to this day.