共动距离计算器 — 公式

Comoving Distance Approximation

At low redshifts the comoving distance is well approximated by the linear Hubble relation.

Formula

d = c z / H0

  • *c* = 299 800 km/s (speed of light)
  • *z* = observed redshift
  • *H0* = Hubble constant

    • The result is in Mpc. For z above about 0.3, higher-order corrections become important.

    计算示例

    A galaxy at redshift z = 0.1 with H0 = 70 km/s/Mpc.

    1. d = c z / H0
    2. d = 299800 * 0.1 / 70
    3. d = 29980 / 70
    4. d ≈ 428.3 Mpc ≈ 1396 Mly