Cosmology

The expanding universe, dark energy, and the cosmic microwave background. Explore the observations and models that describe the universe on the largest scales.

1 exhibit

Cosmic Playground is in active beta. Check each exhibit's readiness badge before assigning; an exhibit with no badge is finished.

Exhibits

Filter these in Explore

Galaxy Rotation Curves

Key idea: Explore why spiral-galaxy rotation curves stay nearly flat at large radius and what that implies about dark matter across scales.

Explore why spiral-galaxy rotation curves stay nearly flat at large radius and what that implies about dark matter across scales.

near-ready Galaxies Cosmology Data & Inference 10–20 min Both

Open exhibit

Key concepts

Learning goals aggregated from all exhibits in this topic.

Interpret galaxy rotation curves as velocity-versus-radius observables inferred from Doppler measurements.
Compare visible-matter-only Keplerian predictions to flat observed curves and infer missing mass.
Relate bulge, disk, and halo component models to total curve shape and enclosed-mass growth.
Use baryon fraction and dark-to-visible ratio readouts to reason about mass budgets at large radius.