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For Educators · Hubble's Law

Hubble's Law for a star cluster

Built for educators teaching it to a class. Drop a live demo into a lecture or assign it as a shareable link — no lab installs. Simulate a star cluster live below — adjust the inputs and watch it respond, right in your browser.

Hubble's Law & RedshiftLive

the expanding universe

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Hubble constant H₀ (km/s/Mpc)

Every distant galaxy recedes at a velocity proportional to its distance: v = H₀·d. This uniform expansion is the same seen from any galaxy — there is no center. The inverse of H₀ gives the Hubble time, a rough estimate of the age of the universe.

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H₀70 km/s/Mpc

Hubble time14.0 Gyr

v at 100 Mpc7,000 km/s

Governing equation

v = H_{0} d = 70 \times 100 = 7, 000 km/s, t_{H} = \frac{1}{H _{0}} \approx 14.0 Gyr

Reading this result: Right in the Hubble-tension zone: this H₀ gives a Hubble time of 14.0 Gyr, close to the measured 13.8-Gyr age of the universe.

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Frequently asked questions

Is this good for educators?: Yes — this version of "Hubble's Law for a star cluster" is framed for educators teaching it to a class. Drop a live demo into a lecture or assign it as a shareable link — no lab installs.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.