Ask why. Follow the evidence.
Design examples
The event deck, evolutionary tree, and lineage examples. A design example does not establish what is playable.
The deck
Every card is something that actually happened, or could. Here is our own solar system. Elsewhere was spotted around another star. Theory is allowed by physics and not found yet. Imagined is hard sci-fi that plays by the rules, in the Archean and after only. The game never passes off a maybe as a fact. Each card has its own link.
Pour it in backwards
Late infall against the spin. Gas falls in, the star brightens, the outer disk tilts or turns the other way.
sourceSeed with soot
A carbon-rich cloud. Oxygen locks in CO, oceans never form, and a diamond layer forms at the world’s core. Beautiful, and lifeless.
sourceTruncate the disk
A close pass in the birth cluster cuts the disk at 50 AU and leaves a detached belt that feeds comets later.
Compress the cloud core
The cloud collapses only when gravity beats what holds it up. Too much spin and it splits in two.
Raise a wall
A pressure bump traps drifting pebbles. The ring you see in ALMA images is where the first planet forms.
sourceBuild the wall early
An early Jupiter core blocks the pebble flux. The inner worlds come out small and dry, as ours did.
sourceSpin a whirl
A vortex gathers dust into a crescent and one large body forms fast on one side of the disk.
Tilt the far one
A distant companion pumps a giant’s eccentricity until tides capture it on a tight orbit, sometimes backwards.
sourceLet it fall
Drag a planet into the star. A thousandfold flash for days, a dust shell, and the only action that pays Power back.
sourceBreak the moon
A moon inside the Roche line becomes rings. Saturn’s may be the remains of a moon lost 100 million years ago.
sourceCatch one backwards
A retrograde captured moon wrecks the original moons and, over billions of years, spirals toward rings.
Knock the giant over
A two-Earth-mass impact tips an ice giant on its side. Its moons form in the new plane and get decades-long nights.
Hide a giant far out
A far planet shepherds the outer belt and times comet showers. We are still looking for ours.
Give the world a ring
A grazing asteroid breaks into an equatorial ring. Its shade cools the tropics for tens of millions of years, then rains down.
sourceCrack the crust
A flood-basalt province. CO₂ up, ten degrees warmer, the seas go anoxic. Then the fresh rock weathers and cools the world.
sourceRoll the world
True polar wander moves continents to the equator, where they weather faster. One route into a snowball.
Drown it
Beyond a few tens of oceans, high-pressure ice seals the seafloor. No land, no weathering, no thermostat.
sourceSpin it backwards
A retrograde day of hundreds of ours. The dynamo starves and the air goes to the wind, as on Venus.
The sky flashes
A gamma-ray burst strips half the ozone for years. The rarest card in the deck, and why Shelter matters.
Gather the lands
A supercontinent dries its interior and warms the world; its breakup rifts, weathers and cools it.
Carry the spark
Rocks blasted off a living world seed its neighbour. A second way for twin worlds to live, and a way back from sterilisation.
Bury the carbon
Organic carbon buried in rifts is the source of free oxygen. The Great Oxidation as something you can hurry, through geology.
sourceRaise the mountains
Collide two plates. Phosphorus flows to the sea and the animals’ window opens sooner.
Green the land
The first forests multiply weathering and push oxygen into the band where fire is possible.
sourceCull the giants
An extinction below sterilising strength kills the largest bodies first and opens niches for the survivors.
Vary the climate
Ice-age cycles select for flexible minds. Arrange a continent on a pole and the brain window opens.
Open the ice
A dark lineage under ice can reach animals on chemical energy, and no further without light. Crack the shell.
The world that was thrown out still lives
An ejected, water-rich world keeps a dark ocean on its own heat. The saddest card gets a second ending.
Floaters in the clouds
Life in a giant’s atmosphere: gas-bag grazers, hunters, sinkers. A thought experiment made a branch, with no ground and no fire.
A colder chemistry
Ammonia or methane as the solvent on a cold world. Slow metabolism, long lives, a lifeform that thinks in centuries.
The thinking forest
A sessile lineage that computes through a shared root network. It cannot move, build or burn; it can remember for ages.
Two as one
An obligate symbiosis: one body for hands, another for thought. Neither gets there alone.
Intelligence without an inside
A lineage that solves and builds without anything it is like to be it. The game can only show its works.
33 of 33 cards · 16 here · 6 elsewhere · 6 theory · 5 imagined
The tree of windows
Nine rungs from first cells to an intelligent lineage. Each one opens only when the world has what it takes. The gates are physics the sim already runs. The waits inside an open window are game design, and the game says so.
intelligence arose more than once here; the tree branches
- R8Intelligenceneeds: fire needs land, hands, oxygen 16–30%0.3 Ma
- R7Big brainsneeds: by branch: land, sea, air, or a colonythe last few Myr
- R6Onto the landneeds: an ozone shield, land, wet–dry cycles470–370 Ma
- R5Animalsneeds: oxygen above the animal floor, flooded shelves0.64–0.54 Ga · oxygen 0.4%: needs about 1%
- scar: snowball, 720 Ma · surface lineages −1 rung, vents untouched
- R4Sex and sizeneeds: phosphorus, oxygen held1.0 Ga · the long calm before
- R3Complex cellsneeds: oxygen above a floor, a warm stable oceanafter the Great Oxidation
- R2The air turnsneeds: the oxygen sinks saturate2.4 Ga
- R1Light-eatersneeds: sunlight on a surface ocean, iron, nutrients3.0–2.7 Ga
- R0First lifeneeds: a pond, a vent, or the dark under ice4.2 billion years ago here
The air turns
Oxygen rises once the planet's sinks saturate. Methane collapses, the world can freeze, ozone forms, the anaerobes die back. One event, four consequences, none of them chosen.
The long calm
A billion years of low oxygen and scarce phosphorus. The stall card explains why nothing is happening and offers the nutrient levers.
Resets are graded
Only a boiled or melted ocean empties the tree. A snowball, an anoxic sea or a UV spike drops rungs by a rule and leaves a scar with its cause and date.
Shape a lineage
Push the system around and watch the lineage change. Gravity sets the body. The star sets the eyes. Oxygen sets what it can burn. Lifespan sets whether it can teach. Same inputs, same creature, every time.
Why?
Beyond the familiar
In the Archean and after the game may borrow from hard science fiction, on one condition: the simulation's physics still gates it. A floater needs a thick atmosphere and no ground. A cold chemistry gives slow life. A thinking forest remembers and cannot move.
Different kinds of life
A colony that thinks with numbers. Two species that live as one. A lineage that builds without any inner life. Each is a branch with its own window, its own constraints, and a trophy that says “imagined”.
What stays fixed
Chemistry needs a solvent, an energy gradient and a way to copy. Intelligence needs time, a stable niche and something to think about. Fire needs oxygen, fuel and land. The imagined branches cannot break these.