A complete interactive universe playground

Zoom from a human
to the edge of the cosmos.

Compare worlds with your own height, race a beam of light, plan journeys between planets, build galaxies, bend spacetime, follow the life of stars and discover how our universe fits together.

Launch the simulations Explore the cosmic atlas
🎯
Today's cosmic discoveryLoading...
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F = GMm/rΒ²
E = mcΒ²
v = Hβ‚€d
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Interactive simulations26Scale, planets, stars and galaxies
Cosmic atlas objects0Worlds, stars and deep sky
Experiments completed0Saved in this browser
Missions completed0/26Earn XP and achievements
Overall progress0%Labs, missions, atlas and quiz
Cosmo the Comet says

Space is mostly empty, but it is never boring. Change one variable at a time and watch what the universe reveals.

Simulation zone

Interactive Cosmos Laboratories

Every simulation has live controls, animation, observations, calculations, explanations and a mission.

Verified relationship Student model Theoretical
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Solar SystemBeginner

Living Solar System

Watch the planets orbit and compare their very different years.

Verified
1 Adjust2 Predict3 Run4 Explain
Ready to explore
Change the controls and press Run
Make a prediction

What will happen?

Cosmic mission

Mission

+40 XPNot completed
Celestial encyclopedia

Interactive Cosmic Atlas

Explore planets, dwarf planets, moons, stars, exoplanets, nebulae, galaxies, black holes and other remarkable objects.

Comparison traySelect up to four objects
Nothing selected yet.
Knowledge library

Cosmos Theory, Made Friendly

Search astronomy, planetary science and cosmology. Every lesson includes a definition, key idea, example and misconception.

Words of the universe

Cosmos Glossary

Search essential astronomy words and build confidence with the language used by scientists.

Problem-solving tools

Cosmic Calculator & Unit Converter

Calculate travel time, orbital motion, gravity, telescope resolution, star properties and more with step-by-step substitutions.

Cosmic formula laboratory

Light Travel Time

Ζ’
t = d/c

ResultEnter values to calculate

Astronomy unit converter

Cross the scales of space

⇄

Convert between astronomical units, light-years, parsecs, planetary masses, speeds, angles and more.

Converted valueβ€”
Game-style learning

Cosmic Missions

Each laboratory contains a practical target. Complete missions to earn XP and unlock achievements.

0 of 26 complete
Knowledge check

Cosmos Mastery Quiz

Ten questions are randomly selected from the full question bank. Every answer includes a friendly explanation.

Mission control

Ready for launch?

Test planets, stars, distances, gravity, light, galaxies and the history of the universe.

Question 0 of 10

Best: 0/10

Press β€œStart new quiz” when you are ready.

Your cosmic journey

Achievements

Unlock badges by experimenting, learning and exploring the atlas.

Explorer log

Cosmos Notebook

Save simulation results and export your discoveries as a text file.

Accuracy and further learning

Trusted science references

Values are rounded for student learning. Object measurements can improve as scientists gather new data.

NASA Solar SystemPlanets, moons, dwarf planets and small bodies. NASA UniverseStars, galaxies, black holes and cosmology. NASA Exoplanet ExplorationWorlds beyond our solar system and detection methods. NASA/JPL Solar System DynamicsOrbits, ephemerides and small-body data. ESA Space ScienceEuropean missions and astronomy resources. International Astronomical UnionAstronomical names, definitions and public resources.