Exordium

Backstory

The purpose of the primary setting on this blog is to consider a realistic path to humanity’s expansion into the wider cosmos and what might be found during that exploration. I will expand upon this at a later date but it will likely include the following concepts:

• Complete colonisation of the solar system
• Human colonisation of nearby star systems
• The divergence of humanity and its technology into various branches
• Automated interstellar probes investigating alien biospheres
• The state of existence of any intelligent alien xenosophonts

Brief descriptions of possible locations have been grouped into six categories. For each of them I have done a variable amount of research into their viability though the basic idea is present. My intent is to write something about each one over the period of the blog, but it might take a while.

Solar System

The Solar System is the cradle of humanity and is still home to the majority of the baseline humans though many info-morphs, neo-humans, wights and geists also live there. While every celestial body is inhabited to some extent, the majority live in the Nimbus, a swarm of habitats orbiting the Sun.

The Diaspora

Humanity has expanded into interstellar space and Alpha Centauri is a thriving colony that is beginning to rival the Solar System. However, the majority of the expansion has been performed by artificial life with computational world ships sailing slowly through the void and far travelling wisps eager to explore the entire galaxy.

Exoplanets

Most locations of interest found by the wisps are devoid of life or only contain simple unicellular prokaryote-like life. They are careful to protect these fragile beginnings and rigorously avoid contamination that might harm them.

Exoecologies

Complex life equivalent to eukaryotes does not necessarily arise in every location but where it does it displays a rich diversity as it adapts to varied environmental conditions to form alien ecosystems.

Achlys

Can an ecosystem form using hydrogen instead of oxygen?

On a moon larger than Earth that orbits a super-Jupiter exists an ecosystem with unusual biochemistry. Strange life swims in ammonia oceans while iron clad bugs crawl the volcanic landscape and perpetually soaring creatures glide in the haze above. To see through the thick atmosphere sophisticated magnetoreception is common, aided by the gas giant’s strong and varying magnetic field.

• Can graphene bilayers be the membrane mimetic materials?
• Photosynthesis in Hydrogen-Dominated Atmospheres
• A Volcanic Hydrogen Habitable Zone

Anemos

What does life need to do to survive on a planet with a highly eccentric orbit?

In an extremely eccentric orbit this planet experiences massive changes in illumination through the year. During “summer” the planet is close to its star and experiences extremely hot conditions. Autumn brings more survivable temperatures as the planet recedes from the sun. Temperatures continue to drop as the long winter arrives and all life stops until spring when the planet again swings towards the sun.

• Habitability and Water Loss Limits on Eccentric Planets Orbiting Main Sequence Stars
• Habitability of planets on eccentric orbits: Limits of the mean flux approximation
• Photosynthetic Potential of Planets in 3:2 Spin Orbit Resonances

Chiaro

Can a world have longer days than nights?

A Mars sized moon orbits a gas giant which is in a polar orbit around an eccentric F-class binary. The light from the two stars reflects from water clouds in the gas giant producing a day-night pattern very different to Earth. The abundant blue light allows lush phototrophic life to grow but the harsh UV levels cause problems for other life. A giant exoskeletal insect-like clade dominates the day and a soft skinned amphibian-like clade the night.

• Energy Budgets for Terrestrial Extrasolar Planets
• Photosynthesis on Exoplanets and Exomoons from Reflected Light
• Polar planets around highly eccentric binaries are the most stable

Elais

On distant worlds can life thrive in frigid seas of liquid hydrocarbons?

A Mars sized planet orbits a distant red star. Upon on its frigid surface lie lakes of liquid hydrocarbons. Underneath lie hidden oceans of water tainted with ammonia. A bounty of organic haze is produced in the upper atmosphere during solar flares. This rains from above like manna from heaven while phototrophs survive on the infrared light that penetrates the haze.

• Solubility of Polyethers in Hydrocarbons at Low Temperatures. A Model for Potential Genetic Backbones on Warm Titans
• Titan as the Abode of Life
• Titan: Earth-like on the Outside, Ocean World on the Inside

Enso

Can life use chlorine in place of oxygen?

Large stars burn bright and die young leaving a cloud of debris rich in heavier elements. This formed a polar accretion disc around its smaller companion. As the debris fell into the star momentum was conserved so that the star rotated faster and faster. Meanwhile a second generation planet was forming in a polar orbit. Due to the higher concentration of chlorine the seas of Enso were a mixture of bleach and hydrochloric acid with chlorine gas in the atmosphere. Despite the hostile environment, life began. Chlorinic photosynthesis evolved to take advantage of the different environment and a range of halocarbons were produced. Some were used as structure materials leading to PVC skeletons.

• The Habitable Zones of Rapidly Rotating Main Sequence A/F Stars
• The Potential Feasibility of Chlorinic Photosynthesis on Exoplanets
• Second Generation Planets

Epimetheus

In what environment would lighter-than-air gasbag life thrive?

A massive super-Earth with a thick carbon dioxide atmosphere orbits a distance F-class star. Frequent asteroid impacts from have slowed its rotation and formed two moons. The continuing supply of dust from above seeds the clouds with nutrients. Volcanic activity and sea spray do the same from below. Due to the scarcity of solid land life moved into the sky to follow day light as it slowly moves around the world.

• The impact of CO2 ice clouds on the outer boundary of the habitable zone
• Outgassing on stagnant-lid super-Earths
• Possibilities for an Aerial Biosphere in Temperate Sub Neptune-Sized Exoplanet Atmospheres

Ginnungagap

Can life exist in the void of space?

A massive and highly eccentric gas giant orbits its host star like a comet, moving between the heat of the sun and the distant icy void. Around this gas giant is a complex system of rings and moons of various sizes. As the planet orbits, ice in the rings sublimates to vapour and refreezes back into ice, continually replenished by emissions from the frozen moons. While simple life began on a moon, it has now moved to colonise the rings and take advantage of the orbital cycle.

• Atmospheric Evolution on Low-gravity Waterworlds
• Cronomoons: origin, dynamics, and light-curve features of ringed exomoons
• What it would be like to live on a comet

Jirin

Is it possible to have an equatorial ice belt without frozen poles?

The planet of Jirin orbits a K-type star slightly cooler than Earth’s sun, yet receives about the same illumination. It is tilted at an angle of around 60° which is much greater than Earth’s 23°. Due to this, averaged over the course of the year, Jirin’s poles receive more illumination than the equator. This results in an equatorial ice belt while the poles remain ice free, even during the long dark winter. Life on Jirin has evolved in a similar way to Earth but the northern and southern hemispheres have diverged significantly as most animals cannot migrate across the frozen equator.

• Enhanced Habitability on High Obliquity Bodies near the Outer Edge of the Habitable Zone of Sun-like Stars
• The Ice Coverage of Earth-like Planets Orbiting FGK Stars
• Multiple Climate States of Habitable Exoplanets: The Role of Obliquity and Irradiance

Jormungandr

How much life can an almost completely ice covered world support?

A frozen world slightly smaller than Earth exists with only an equatorial belt of open ocean that moves with the seasons like a serpent encircling the world. Light from a star slightly warmer than the Sun penetrates the thin ice to support algae living on the icy ceiling. On the sea bed life survives on mana from above and chemicals from below. Under the thick ice, life extracts energy from thermal, ionic and osmotic gradients to survive. Scattered volcanic islands penetrate the ice and provide oases for the rare terrestrial life.

• The Jormungand global climate state and implications for Neoproterozoic glaciations
• Sea ice, extremophiles and life on extra-terrestrial ocean worlds
• Strategy for Modeling Putative Multilevel Ecosystems on Europa

Khione

Can life exist on a frigid moon with lakes of liquid nitrogen?

On the icy moon of Khione, far distant from its sun life has evolved in the dark frigid depths of an ocean sealed beneath the ice. A parallel lineage of life has even managed to adapt to the liquid nitrogen found under such conditions, though rarely do the water and nitrogen adapted life interact.

• Many Chemistries Could Be Used to Build Living Systems
• On the Potential of Silicon as a Building Block for Life
• Triton: Fascinating Moon, Likely Ocean World, Compelling Destination!

Khthonia

How would life evolve on a world exposed to a wider spread of wavelengths of light?

A planet slightly more massive than Earth orbits a close twin red dwarf binary. Khthonia formed as a mini-neptune but over time flares from the red dwarfs have converted it into a tidally locked Earth-like habitable evaporated core. Not only has life adapted to survive the frequent flares, it also harvests light across the entire spectrum from ultraviolet flares to the short wave infrared.

• Circumbinary Habitability Niches
• Habitability Properties of Circumbinary Planets
• Habitable Evaporated Cores: Transforming Mini-Neptunes into Super-Earths in the Habitable Zones of M Dwarfs

Maelstrom

Can life survive in a purely aerial environment?

Seeded with simple life from elsewhere, this mini-Neptune became a home for life that remains permanently floating in the air. It ascends to take advantage of clearer skies and more abundant sunlight. As it grows it becomes heavier and sinks towards the core. Before reaching the infernal depths below it must reproduce to begin the cycle anew.

• Atmospheric Habitable Zones in Y Dwarf Atmospheres
• Brown Dwarf Atmospheres as the Potentially Most Detectable and Abundant Sites for Life
• Possibilities for an Aerial Biosphere in Temperate Sub Neptune-Sized Exoplanet Atmospheres

Mokopele

What if life adapted to live on a world like Venus?

Before Venus succumbed to a runaway greenhouse effect it is perhaps possible that life evolved. What if on a similar planet elsewhere, life managed to adapt and thrive in the changing conditions? Could it survive in seas of sulfuric acid or “swimming” in supercritical carbon dioxide? Or would it retreat to the temperate upper atmosphere? Perhaps its survival was only possible since it was silicon based?

• Evaluating Alternatives to Water as Solvents for Life: The Example of Sulfuric Acid
• Supercritical Carbon Dioxide and Its Potential as a Life-Sustaining Solvent in a Planetary Environment
• The Venusian Lower Atmosphere Haze as a Depot for Desiccated Microbial Life: A Proposed Life Cycle for Persistence of the Venusian Aerial Biosphere

Phytos

Can plants take on the role of animals?

In the distant past, the Mars sized world of Phytos suffered a large impact which slowed its rotation to a crawl and filled its skies with moons. Due to the low gravity and weak magnetic field, despite the evolution of oxygenic photosynthesis, a thick oxygen rich atmosphere was unable to form. However, by moving to follow the sun, phototrophic organisms could continually generate ample oxygen for their own respiration, unlike the simple animal-like worms. Eventually they colonised the land and diversified into a range of phototrophic clades. Floating gasbags, gliding “leaves” and other forms all managed to move at the slow pace required to remain in perpetual sunlight. A rich ecosystem formed where photosynthetic organisms dominate over the simpler anaerobic animals.

• Animals thrive without oxygen at sea bottom
• The Physics, Biology, and Environmental Ethics of Making Mars Habitable
• The Physiological Ecology of Vascular Epiphytes

Spinyx

What would life be like on a planet where the sun rises in the east and sets in the north?

In the distant past an impact event shattered the small planet of Spinyx causing it to tumble through the void surrounding by a cloud of debris. Due to the high angular momentum and irregular shape, its rotation was chaotic. This produced an unpredictable day/night cycle on the planet. Surface illumination was further complicated by the ring formed from the debris and the small family of moons surrounding Spinyx. Life evolved in the dynamic environment of the oceans despite never experiencing a regular natural cycle.

• Atmospheric evolution on low-gravity waterworlds
• Cronomoons: origin, dynamics, and light-curve features of ringed exomoons
• Triaxial deformation and asynchronous rotation of rocky planets in the habitable zone of low-mass stars

Tezca

Where could silicon-based life be found?

Around a dying ember of a cooling white dwarf orbits a planet rich in carbon formed from the debris of a supernova. All its water has been boiled away leaving hydrocarbon and hydrogen cyanide oceans. Among silicon carbide rocks a dark mirror of Earth life has evolved that is based on silicon not carbon. Silicon crystal wings are raised to capture the perpetual sunlight and power the ecosystem.

• Extrasolar Carbon Planets
• Habitable Planets Around White and Brown Dwarfs: The Perils of a Cooling Primary
• On the Potential of Silicon as a Building Block for Life

Thelion

How would life evolve and adapt to the dark side of a tidally locked world?

Thelion is a mini-Neptune covered with a thick hydrogen atmosphere and a global ocean. Such a world is known as “hycean”. It is tidally locked to a dim red dwarf causing the sun facing side to be uninhabitably hot. Only near the terminator can phototrophic extremophiles exist to take advantage of the continual sunlight. However, enough heat is transferred by the ocean and thick atmosphere to cause the “night” side to retain a habitable temperature. A faint sliver of light is periodically provided by the distant G-dwarf companion star, though it cannot support a rich ecosystem on its own.

• Effects of a Binary Companion Star on Habitability of Tidally Locked Planets around an M-type Host Star
• Habitability and Biosignatures of Hycean Worlds
• The Runaway Greenhouse Effect on Hycean Worlds

Xeros

Can a barren desert planet produce giant sand worms?

A second generation planet formed around a white dwarf / red dwarf binary from the debris of the white dwarf’s birth. Xeros was baked almost dry while the white dwarf cooled and what remained became a cold volcanic desert. Most of the planet is barren but life stubbornly thrives in a few footholds. From the salty lakes on the light side to the temporary buffer between ice and lava on the dark side. In scattered locations, plentiful volcanic gas bubbles from beneath the sands to produce a fluidised mixture through which larger organisms can move… and hunt.

• Second generation planets
• Swimming in granular media
• Titania may produce abiotic oxygen atmospheres on habitable exoplanets

Yomi

What sort of life could exist on a planet orbiting a pulsar?

A dark planet with an atmosphere vastly thicker than Earth’s orbits a pulsar. It is warmed by the extreme x-rays and solar wind produced by the pulsar. The surface in the stygian gloom below is habitable in a way, though the strange life that swims through supercritical carbon dioxide is not at all like that on Earth.

• Neutron star planets: Atmospheric processes and irradiation
• Supercritical Carbon Dioxide and Its Potential as a Life-Sustaining Solvent in a Planetary Environment
• Zapped By Radiation, Fungi Flourish

Exocivilisations

While life appears to be relatively common in the galaxy, evidence of advanced alien technological civilisations is much rarer. Unfortunately, in almost all cases that life is extinct and only their technology remains. While the causes of their extinction are varied, this goes some way to explaining the Fermi Paradox.

Myrmidons

Despite their wide ranging exploration the wisps have only discovered a single instance of an interplanetary exocivilisation. The myrmidons are however not at all like humanity. It is unclear whether they are an evolved organic species or an artificial biotech lifeform that travels between stars as spores to colonise other planets via directed panspermia. So far no communication has been possible with either the individual animal-like mobile lifeforms or the planet covering mycelial fungus-like structures.