Follow the path of stardust — from hydrogen to the eight planets and the Sun.
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Fuse elements
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Fill your element stock
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Craft building materials
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Create celestial bodies
1Fusion Reactor — Stellar Nucleosynthesis
Choose two starting substances. Hydrogen (H) is available without limit — every heavier element you must first fuse yourself. Click a slot to empty it.
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Reaction:Choose two elements …
Product:—
2Element Stock
Collected elements are processed into building materials. Stock is capped at 6 per element — use it up regularly to make room for more.
No elements yet — start your first fusion!
☀The Fusion Chain of Stars
This is how real stars build up heavier elements — step by step, alpha particle (helium nucleus) by alpha particle. Reactions marked in green are ones you've performed at least once.
3Craft Building Materials
Combine elements into the four building materials that make up every celestial body in different proportions. A green ingredient means you have it. Building materials are consumed when you create celestial bodies.
4Create Celestial Bodies
Combine building materials in the right composition to create planets — and finally the Sun itself. The bigger the body, the more material it needs.