Image from Steve Bowers
Panthalassa is a waterworld with oceans 75 km deep

Panthalassa - Data Panel

System:JD 34420682
Primary:JD 34420682
Stellar Type:K0
Luminosity:0.4x Sol
Region:Terragen Middle Regions - Constellation Sagitta - Distance from Sol 890 ly
Planets:Panthalassa (waterworld) 0.7 AU (3.85 x Earth mass) (diameter of Panthalassa 20530 km)
Cassidy (Jovian type) 4.2 AU (2.8 x Jupiter mass)
Wanda (Subjovian type) 8 AU (0.2 x Jupiter mass)
Affiliation: Originally Zoeific Biopolity, currently Panthalassan Ocean Fleet

Discovery and Colonisation

Panthalassa was discovered by astrometry during the Interplanetary age by Julie Denley and identified as a giant water rich planet with an oxygen-bearing atmosphere. However the Quercus robur, a seedship of the Zoeific Biopolity, the first ship to reach this system did not arrive until more than three thousand years had passed, in 3377 a.t. The Biopolity planetologists surveyed this remarkable world, with its primitive ecosphere, in detail and determined that colonisation was possible.

Massing 3.85 as much as Old Earth, the surface gravity of this world is 1.5gee; the formation of this single body in the inner system 2.4 billion years ago collected a large proportion of the water in the early solar system of JD 3442068. Today Panthalassa holds the equivalent of 352 times all the water in the oceans of Earth. The inner metallic core and outer silicate core together have a radius of 9920km, this is covered by a mantle of dense high pressure water ice 270km thick, and finally an ocean of liquid water 75km deep giving an overall radius of 10265km. The radioactive elements in this relatively young world produce a respectable amount of internal heat, and the ice mantle exhibits a slow convection to transmit this heat to the outer surface, and cryovolcanic events on the sea bottom are frequent, causing mixing of the lower sea levels; the ocean is rich in sulphate and nitrate ions but relatively deficient in chlorine. Carbon dioxide is also expelled into the ocean and eventually the atmosphere.

The original atmosphere of Panthalassa was mostly water vapour and ammonia, this last compound brought in by comets from outside the orbit of the gas giant Cassidy; the action of sunlight on this atmosphere over time broke the water and ammonia down into oxygen and nitrogen, while the hydrogen formed by this photolysis escaped into space. A corrosive nitric acid atmosphere did not form, however, due to the emergence of primitive life in the photic zone at the top of the ocean. By the time the Quercus robur arrived, a number of plant-like and moneran-like kingdoms had developed, maintaining the delicate balance of oxygen, nitrogen and carbon in the upper layers above the thermocline, and regulating the acidity of the water.

After a generation of genetic tweaking the Biopolity dnabrain on the Quercus developed a race of ocean-going human colonists and food species compatible with the local biochemistry, and soon the equator of Panthalassa was ringed by a series of floating cities, each one a colonial organism geneered from the local life and extracting energy from the sea by Ocean Thermal Energy Conversion. The first Golden age of Panthalassa had begun, and the charismatic merhuman Harld Seeger became the dominant figure in Panthalassan politics, with his positive and hospitable philosophy of life. Soon many ocean-adapted species had been drawn to this giant seaworld.

The Zoeific Biopolity were involved in the provolution, or proactive evolution, of a class of sea-dwelling alien creatures discovered on Fuego, a Europan type moon 500 ly distant from Panthalassa; by 4500 a species of fully intelligent alien provolve had been developed, the Lignosagittae. Many of the new species developed an obsession with various galactic nebulae, and set off in relativistic fleets of ships to visit these distant objects; but those who remained behind built a complex new society on the world of New Charon. Harld Seeger, now Permanent Speaker, invited the new race to join in the development of the vast waters of Panthalassa, and soon the largest population of Lignosagittae (also known as Gnosags) in the Galaxy were to be found in the deep waters of this planet.

A number of specialised morphotypes were developed by the Gnosag bioengineers; the Browser clade were symbiotic with a surface floating colonial city-organism, which trailed streamers of chemotrophic life deep into the ocean to supply the Browsers with food; this clade most closely resembled the ancestral creatures on Fuego (still living on that world in a primeval, undisturbed condition, protected by Biopolity protocol). The Spearhead clade, on the other hand, were fast predators, chasing the fish-like creatures developed by the Biopolity to live in the upper ocean layers of Panthalassa. Finally the Eyeless clade adopted the lower regions of the ocean as their home, where the organic detritus from the upper oceans rained down to the slushy phase-change water-ice boundary; an extreme environment, beset by icequakes and outgassing, with a pressure approaching 1.1 gigapascals.

The Zoeific Biopolity was essentially neutral in the Version War, although it caused the destruction of most of the local wormhole links; during this time Panthalassa developed by itself, and the first golden age came to an end.

The Eyeless War

Over time the Eyeless civilisation became isolated from the rest of Panthalassan society, and developed several regional nation-states; warfare occurred in the deeps, difficult to observe because of the intervening water. The deep water survivors of this conflict were ruthless, unpredictable and barbarian, attacking merhumans and Spearhead gnosag hunting parties for little apparent purpose.

The Permanent Speaker Harld Seeger and the chief of the Browser clade (who was known by the designation 56,78,2, a reference to the position e occupied in the Browser traditional formation dance) formed an alliance for the defence of the surface world. When attacks and abductions into the deep continued a joint task force was formed, but the pacification of the vast tumbled high-pressure landscape with its scattered temporary villages proved difficult, and in 6211 AT 56,78,2 emself was killed in combat with a gang of heavily armed gnosag bandits.

Er place was taken in the command structure by the chief of the Spearhead clan, 1,1,32, who was an aggressive individual, prone to the obsessive nature of his species. Over a period of several decades the deeps were systematically made secure by force of arms, a process which came to appal the genial Seeger. In due course the surviving members of the Eyeless species began to tell the story of their own struggle for survival at the bottom of the ocean, a tale of appalling hardship, which went some way to explain, if not excuse, the barbarity of their former way of life. Following this episode Harld Seeger opted to become an ascended posthuman entity and left this solar system to pursue his own destiny in the greater Noosphere.

The Ocean Fleet

Panthalassa now became a vast world ocean civilisation, with the intense personality of 1,1,32 driving the many species of water dwelling creature to ever-greater achievements. Merpeople, including the giant Zennorian mermen, whales and dolphins, provolved arthropods and the various species of intelligent gnosags flocked to his banner. The very plankton in the sea was gengineered to have limited processing ability; so no part of the vast ocean was now out of reach of broadband communications. This was the second golden age, and the ocean-dwellers began to look abroad for new territories to conquer.

The Panthalassan Ocean Fleet set off in 6501 to seek new worlds in the Sagitta/Aquila sector. In an ever-increasing cone pointed roughly away from Old Earth the Ocean Fleet continues to find new systems suitable for water-dwelling civilization. Waterworlds and earth-like ocean/continental planets occur in some systems, but are absent from a great many more; however the Ocean Fleet (under the inspired leadership of various copies of 1,1,32) has developed a strategy which results in several artificially created water-rich worlds in all but the most inhospitable systems.

A stable torus-shaped swarm of solar collecting satellites is established in close orbit around the local star; around the outside of this swarm orbit thousands of coherent light sources, each aimed at an icy body in the solar system. From the viewpoint of the distant icy world the light sources form a continuous strip as bright as the Sun as seen from Earth (or brighter). Over a period of hundreds or thousands of years the icy outer system worlds melt and separate into waterworlds with rocky cores, and are inhabited by the many customer species of intelligent aquatic life that the Fleet has attracted into the Sagitta sector. Icy bodies from a few to more than ten thousand kilometres in diameter have been converted in this way.

As the Ocean Fleet has extended its reach, the original copy of 1,1,32 has found it necessary to transcend several toposophic levels and become a minor Power; other copies still operate at a similar toposophic level to most humans, but are active in spreading the water world lifestyle in many parts of the galaxy; in particular the copy 1,1,32d has become involved in the controversial movement for the Liberation of Xenosophonts, and the abortive Freedom for Paulans incident.

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Development Notes
Text by Steve Bowers
Thanks to Grant Hutchison for the parameters of this world
Initially published on 08 October 2008.