Calcolatore Distanza Propria — Formula

Proper Distance

The proper distance is the physical distance between two objects at a particular moment in cosmic time.

Relation

d_proper = a(t) * d_comoving

  • *a(t)* is the cosmic scale factor (a = 1 today)
  • *d_comoving* is the comoving distance

    • At the present epoch a = 1, so proper distance equals comoving distance. In the past (a < 1) the physical distance was smaller.

    Esempio Risolto

    A galaxy with comoving distance 428 Mpc observed at the present epoch (a = 1).

    1. d_proper = a(t) * d_comoving
    2. d_proper = 1.0 * 428
    3. d_proper = 428 Mpc ≈ 1396 Mly