This is a simple cosmology calculator. It can be used to compute the age of the universe for a given set of parameters, as well as the comoving distance and light travel time for a given redshift.

  Parameter Symbol Value Unit
  Hubble constant H0 km/s/Mpc
  Matter density Ωm  
  Dark energy density ΩΛ  
  Radiation density Ωγ  
  —  Spatial curvature Ωk  
  Age of the universe t0 13.788 Gyr

  Redshift z  
  Age at redshift t 0.398 Myr
  Light travel time   13.788 Gyr
  Comoving distance d 13909.09 Mpc
  Transverse comoving distance dT 13909.09 Mpc
  Angular diameter distance dA 12.63 Mpc
  Luminosity distance dL 15313908.98 Mpc

The age of the universe at redshift z is calculated using [1]:

t(z)=1H01/(1+z)0dxxΩΛ+Ωkx2+Ωmx3+Ωγx4.

The comoving distance, in turn, is calculated as

d(z)=cH0z0dxΩΛ+Ωk(1+x)2+Ωm(1+x)3+Ωγ(1+x)4.

The transverse comoving distance is related to the comoving distance by dT=sinh(K d)/K where K=(H0/c)2Ωk. When K=0, this is just the same as the comoving distance. (The expression is real-valued even when K<0; in that case, an equivalent form using the ordinary sine function and K can also be used.)

The angular diameter distance and luminosity distance are given by dA=dT/(1+z) and dL=dT(1+z), respectively.

Results may differ from those calculated using other cosmology calculators because of different rounding (in numerical integration, in particular) and, well, because this one is brand spanking new and may have bugs!


[1] Weinberg, S: Cosmology, Oxford U. Press (2008)