Free Cosmic Expansion Rate Calculator

Estimate the recession velocity of a distant galaxy from the Hubble-Lemaitre law v = H0 * d, where H0 is the Hubble constant.

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km/s/Mpc
Mpc

Recession Velocity

7,000.00 km/s

Recession Velocity (m/s)7,000,000.00 m/s

Recession Velocity vs Hubble Constant (H0)

View formula & how it works →

How the Cosmic Expansion Rate Works

Edwin Hubble discovered that galaxies recede from us at speeds proportional to their distance.

Hubble-Lemaitre Law

v = H0 * d

  • *H0* is the Hubble constant (around 70 km/s/Mpc)
  • *d* is the co-moving distance in megaparsecs

    • This linear relation holds for nearby galaxies; at cosmological distances, corrections from the Friedmann equations are needed.

    Example Calculation

    A galaxy sits 100 Mpc away with H0 = 70 km/s/Mpc.

    1. 01v = H0 * d
    2. 02v = 70 * 100
    3. 03v = 7 000 km/s

    Frequently Asked Questions

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