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∑ The maths › Cosmic timeline · open the lab →

Cosmic timeline: the maths

Mostly published data: each event's date is taken from the literature, not computed here. One curve is computed: the measured rate of star birth over cosmic time.

Equations

ψ(z) ∝ (1 + z)2.7 / [1 + ((1 + z)/2.9)5.6]
The cosmic star-formation rate against redshift z — Madau & Dickinson's fit to the measurements.
t(z) = ∫ da / (a H(a)), a = 1/(1 + z)
Turning redshift into time since the Big Bang, with the same ΛCDM universe as the other labs.

Constants

Ωm, ΩΛ0.315, 0.685Planck (2020)
H₀67.4 km/s/MpcPlanck (2020)

Data, not a simulation: the numbers here are published values, shown as they are. The sources below are the tables.

Worked examples ✓ checked on every change

When star birth peaked ('cosmic noon')3.5 billion years after the Big Bangthe fit's peak, turned into time independently
Today's rate, as a share of the peak11%roughly a tenth

The app's test suite puts the lab in each setup, reads the lab's own result, and fails if it strays from these values.

What's simplified

  • Event dates are rounded; the far future is extrapolated from today's physics (Adams & Laughlin 1997) and tagged by how sure it is.

Where it breaks

Early events (before about a second) and the far future carry the tags CONTESTED or SPECULATIVE — each event says which.

Sources: P. Madau & M. Dickinson, ARA&A 52, 415 (2014); Planck Collaboration (2020); F. C. Adams & G. Laughlin, Rev. Mod. Phys. 69, 337 (1997).

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