CosmosForge Play — astrophysics in your browser

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Stellar Evolution Step through a star's ten life stages, then race to put the lifecycle in order.

Black Hole Explorer Drag the mass, grow the event horizon, and feel gravity stretch time.

Exoplanet Transit Lab Find planets the way Kepler does — a transit dips the starlight. Predict, then reveal.

Gravity Lab How much would you weigh on the Moon or Jupiter? Predict — weight = mass × gravity.

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Explore the cosmos

Gravity Lab How much would you weigh on the Moon, Mars, Jupiter, or Saturn? Predict first — weight = mass × gravity, and your mass never changes. Starlight Decoder Read a star's spectrum the way astronomers do — each element leaves a fixed pattern, and light stretched toward red means it is racing away. Exoplanet Transit Lab Find planets around other stars the way Kepler and TESS do — a transit dips the light. Predict which star has a planet and how big. Name That Constellation See a real star pattern, connect the dots to trace the figure, then name it — the Big Dipper, Orion, Cygnus, the Southern Cross and more. Stellar Evolution Step through a star's ten life stages, then race the clock to order the lifecycle and see how a star's fate branches on its mass. Black Hole Explorer Drag the mass and watch the event horizon grow. Move an observer inward and feel gravity stretch time — with the physics behind Sagittarius A*. Cosmic Distance Ladder How do we know how far away anything is? Climb the four techniques — geometry next door to redshift at the edge of the observable universe.

Practice & play

Mixed Practice A short round across the kits you have played — brought back to make it stick. CosmosForge Sprint Race your OWN best on what you already know. Timer optional, no penalty for a miss. Trick Questions Brain-teasers with a twist — spot why the obvious answer is a trap. Teach the Cast Teach an astronomy idea to a cast member still learning it — teaching makes it stick. Cosmos Duel 2–4 players take turns on one device — same questions, highest first-try score wins. Cosmic Voyage A progression voyage through every kit — clear each stop of real practice, then travel on. Progress Your levels, streak, and how each skill area is coming along — saved on this device. Progress report For grown-ups — a private on-device snapshot mapped to the skill areas. Export a CSV or print.

Concept Kits — 16 kits from the solar system out to cosmology

From the solar system and stars up through gravity, galaxies, and space exploration — a short round with a hint whenever you get stuck. Progress stays on this device.

More ways to play

Cosmos Run Payload vs. Range

Meet the cast — the characters who teach this

Each one stands for an idea you’ll practice. Tap a character to read their illustrated story and hear their audio drama.

Ensemble stories — the cast together

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📚 Books for CosmosForge

Read the story, print a workbook, or color the cast — free PDFs to read offline or print at home.

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