the life of a planet, from dust to civilization
Migrate the orbit — 100⚡ per 0.1 AU.
The planet drifts at 0.1 AU per 1M years.
Crash an asteroid — 100⚡.
Pick any rock on the belt map; it flies in at 0.1 AU per 1M years.
4.6 billion years ago, Earth was one of these — a nameless rock in a swarm around a young sun. It grew by devouring its neighbors, melted from the violence of its own assembly, cooled, and rained out an ocean. Then something rare happened: its crust cracked into moving plates.
Of every world we know, only Earth's lid moves. Plate tectonics stirred the deep, fed the air, and held the climate steady long enough for everything else.
Your task: build a world whose lid cracks. The Task button (under ⚡) tracks every requirement and how to reach it.
Build a world whose lid cracks into moving plates.
Every planet begins as rubble. The young sun's disk was a belt of colliding rocks; the biggest ate the rest, and the energy of all that infall kept the growing Earth molten — a magma ocean under a sky of steam and rock vapor. Iron sank to the center and built a core; the light rock floated toward the skin. When the bombardment ended, the surface cooled, the steam fell as a world-ocean of rain, and the first solid crust froze over the deep heat like ice on a pond.
A crust alone is not tectonics. Beneath it the mantle still churns, and water weakens rock enough for that churning to crack the lid and drag its pieces — plates. Subduction pulls old floor down, ridges make new floor, continents ride the traffic. That conveyor is Earth's thermostat and its recycler; without it, worlds seal shut like Venus or go quiet like Mars.
You have the same ingredients — mass, heat, water, time — and a few powers Earth never had.
Earth's ocean was alive within a few hundred million years of existing — chemistry in warm water, fed by phosphorus that rain weathered out of bare rock, crossed into self-copying and never stopped. For ages life stayed small and dark, hugging the vents. Then some lineage learned to eat sunlight, and everything changed: photosynthesis exhales oxygen.
The sky did not fill at once. For hundreds of millions of years the ocean's dissolved iron drank every breath of it, rusting into the banded iron beds miners dig today. Only when the rust was done could oxygen flood the air — the Great Oxidation. Your planet will find its own date. Hunting can emerge before the sky fills; oxygen then lets consumers gain more from each meal, helping them pay for movement and growth. An ozone shield formed from that same oxygen, and life finally dared the naked land.
None of this is scripted here. Lineages mutate, epigenetic marks steer the search, and every milestone below is an observation the simulation may reach a different way — or on a different clock — than Earth did. Coastal ground can support microbes where moisture and food permit it; drying, UV and starvation can take those colonies away. Landfall records a colony that persists and reproduces, beyond trait readiness. Completed milestones record history; the Life tab shows the populations and resources present now.
What is pulling the thermometer, and how hard — each factor's push on the HUD's median ground over the next 1M years, at today's state.