Rubin's flat curves

World 5: The Missing Mass: Dark Matter is part of PRO

The first world of Cosmos: Big Bang to Now is free. PRO opens the other 25 lessons in 6 worlds — simulations, quizzes and all.

• 🔒 Orbits in a galaxy: how Kepler predicts the speeds
• 🔒 More evidence: clusters, lensing and the Bullet
• 🔒 What could it be? And what we don't know
• 🔒 Galaxies are not alone: groups and clusters
• 🔒 Tidal tails and mergers

$8.33/mo, billed yearly ($99.99) · or $39.99 monthly