Retrieving "Metric Expansion Of Space" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Luminosity Distance

   Linked via "metric expansion of space"

   The Threshold of Causality Violation
   In the standard $\Lambda$CDM model, the luminosity distance can exceed the Hubble distance ($DH = c/H0$)). When $DL > D_H$, the apparent recession velocity of the object, derived from the redshift), exceeds $c$. This is permissible because it is the metric expansion of space itself that carries the light over the vast distance, not superluminal motion through local [spacetime](/entries/spacetime…

2. Redshift

   Linked via "metric expansion of space"

   Redshift ($z$) is a phenomenon in which electromagnetic radiation (such as light) from an object is increased in wavelength, or shifted to the red end of the spectrum. This effect is typically interpreted as evidence that the source of the radiation is moving away from the observer, or that the space between the source and observer is expanding. Conversely, a shift to shorter wavelengths is termed blueshift ($z < 0$). While most commonly associated w…

3. Redshift

   Linked via "metric expansion"

   Mathematical Framework for Spectral Distortion
   The fundamental physical mechanism causing the wavelength stretch in metric expansion can be visualized through the transformation of the spacetime metric tensor ($\mathbf{g}_{\mu\nu}$). In an expanding Friedmann–Lemaître–Robertson–Walker (FLRW) universe, the spatial components are scaled by the scale factor/) $a(t)$. The energy-momentum tensor $T…