Precursor Comets

Precursor Comets (𐑐𐑮𐑰𐑒𐑻𐑕𐑼 𐑒𐑭𐑥𐑩𐑑𐑕, PCs) are a series of celestial objects known for carrying organic compounds capable of seeding life on the planets they pass. Their origin and their final destinations remain shrouded in mystery.

Precursor Comets are composed of a unique mix of materials, including water ice, dust, and a rich array of organic compounds, which differentiate them from ordinary comets. These organic compounds encompass the building blocks essential for the development of life, such as amino acids, nucleic acids, and simple sugars. Additionally, an extensive variety of lipids and phospholipids which lay the foundation for cell membrane structures are also present within the comets.

The process through which life is seeded by Precursor Comets is hypothesised to stem from the comets traversing the vicinity of planetary bodies. As they draw near, the PC's spectral properties trigger a process in which the organic building blocks are released, often through comet sublimation or fragmentation. Such material enters the planetary atmosphere, eventually leading to the formation of primary chemical reactions that form self-replicating systems, setting the stage for abiogenesis, or the emergence of life from non-life.

Radioisotope measurements of certain cometary samples have offered small glimpses into their origins, suggesting that they have travelled vast distances through the cosmos, potentially from other galaxies. While their point of origin remains elusive, the presence of diverse isotopic compositions supports the idea of a diverse array of chemical environments in which these life-seeding agents may have originated.

Precursor Comets are considered to be ancient, with some estimates indicating that they have been circulating throughout the universe for billions of years. This hypothesis, combined with the successful transfer of organic compounds and the development of life across the cosmos, has only deepened their enigmatic nature.

PC-1 is credited with the introduction of life on Delton, a planetary body that has since become home to a diverse array of living organisms. PC-2 is remarkable for having seeded life on all five planets within the Navareo system independently, fostering unique ecosystems across the entire system. Meanwhile, PC-3's course resulted in life being brought to both Tallis and later, Earth. This occurrence suggests that the life found in the Solar System may be connected to that on Tallis.

PC-V diverged from other Precursor Comets in that it was composed mainly of silicon, eventually forming the planet Varyn. Through a unique process, the planet itself developed into a massive silicon-based life form which eventually fragmented into the Varyn species. PC-5 was responsible for introducing life to the Ring Worlds, a collection of planets that exhibit complex ecosystems within their individual ring structures.

In addition to these larger-scale events, many smaller comets seeded life throughout the so-called 'Minor Worlds', encompassing countless planets thriving with unique forms of life. The presence of the Precursor Comets has significantly shaped the development of life across the universe, leaving an indelible mark on the history of countless worlds.