Hubble Diagram: Velocity vs. Distance Fit (2D)

🌌 Hubble Diagram

The classic 1929 plot: each galaxy's redshift-derived recession velocity (y-axis) against its distance (x-axis). A straight line through the origin — Hubble's Law, v = H₀·d — fits real galaxies remarkably well, with scatter from each galaxy's own "peculiar" motion through space.

🎛 Fit & sample

Hubble constant H₀ 70 km/s/Mpc Number of galaxies 60

v = H₀ · d | z ≈ v/c | T_H = 1/H₀

📊 Live readout

H₀ (slider)

70 km/s/Mpc

Best-fit H₀

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Age of universe

13.97 Gyr

Galaxies plotted

ℹ️ Reading it

Each dot is a galaxy at a real comoving distance with a redshift-derived velocity v = H₀_true·d plus a random peculiar velocity (its own gravitational motion, typically a few hundred km/s). Drag H₀ to rotate the dashed line and try to match the cloud of points; click Best fit to see the least-squares line the data actually supports, and its slope is the measured Hubble constant.