Cosmology · v ≈ c z (low z)
Redshift Recession Velocity
The recession velocity implied by a small cosmological redshift, v ≈ cz. This linear form holds only for low redshift; at large z the full relativistic and cosmological treatment is required and this approximation overstates the speed.
Recession velocity2997.9km/s
Formula: v ≈ c z (low z)
Worked example
With the default inputs, redshift recession velocity evaluates to 2997.9 km/s — z = 0.01 → ~2998 km/s. The validator recomputes this against the known value on every build, so the formula is checked, not asserted.
Highlights
- ›Valid only at low redshift
The physics behind it
Knowledge connections
- Associated withCosmological Redshift
Sources
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.