# The kinematic origin of the cosmological redshift

@article{Bunn2009TheKO,
title={The kinematic origin of the cosmological redshift},
author={Emory F. Bunn and David W. Hogg},
journal={American Journal of Physics},
year={2009},
volume={77},
pages={688-694}
}
• Published 7 August 2008
• Physics
• American Journal of Physics
A common belief about big-bang cosmology is that the cosmological redshift cannot be properly viewed as a Doppler shift (that is, as evidence for a recession velocity) but must be viewed in terms of the stretching of space. We argue that, contrary to this view, the most natural interpretation of the redshift is as a Doppler shift, or rather as the accumulation of many infinitesimal Doppler shifts. The stretching-of-space interpretation obscures a central idea of relativity, namely that it is…
62 Citations

## Figures from this paper

### The kinematic component of the cosmological redshift

It is widely believed that the cosmological redshift is not a Doppler shift. However, Bunn & Hogg have recently pointed out that to solve this problem properly, one has to transport parallelly the

### Cosmological redshift in Friedmann–Robertson–Walker metrics with constant space–time curvature

Cosmological redshift z grows as the Universe expands and is conventionally viewed as a third form of redshift, beyond the more traditional Doppler and gravitational effects seen in other

### Observations and inhomogeneity in cosmology

We interpret distance measurements from nearby galaxies, type Ia supernovae, and gamma-ray bursts in the light of a cosmological model that incorporates a spatial averaging technique to account for

### Astronomical redshifts and the expansion of space

In homogeneous cosmological models the wavelength $\lambda$ of a photon exchanged between two fundamental observers changes in proportion to expansion of the space $D$ between them, so

### On cosmological expansion and local physics

• Physics
General Relativity and Gravitation
• 2021
We find an exact convergence in the local dynamics described by two supposedly antagonistic approaches applied at the local, solar system scale: one starting from an expanding universe perspective

### Light propagation in inhomogeneous and anisotropic cosmologies

The standard model of cosmology is based on the hypothesis that the Universe is spatially homogeneous and isotropic. When interpreting most observations, this cosmological principle is applied

### Teaching cosmology with special relativity: piecewise inertial frames as a model for cosmic expansion

This article presents a simple model that reproduces key concepts of modern cosmology within the framework of special relativity, at a level that is suitable for an undergraduate or high school

### There was movement that was stationary, for the four-velocity had passed around†

Is the Doppler interpretation of galaxy redshifts in a Friedmann–Lemaitre–Robertson–Walker (FLRW) model valid in the context of the approach to comoving spatial sections pioneered by de Sitter,

### Implications of an Absolute Simultaneity Theory for Cosmology and Universe Acceleration

It is shown that ALT is compatible with current experiments to test Lorentz invariance only if the proposed preferred reference frame is locally equivalent to the Earth-centered non-rotating inertial reference frame, with the inference that in an ALT framework, preferred reference frames are associated with centers of gravitational mass.

### The apparent (gravitational) horizon in cosmology

• F. Melia
• Physics
American Journal of Physics
• 2018
In general relativity, a gravitational horizon (more commonly known as the “apparent horizon”) is an imaginary surface beyond which all null geodesics recede from the observer. The Universe has an

## References

SHOWING 1-10 OF 25 REFERENCES

### IS SPACE REALLY EXPANDING? A COUNTEREXAMPLE

In all Friedman models, the cosmological redshift is widely interpreted as a consequence of the general-relativistic phenomenon of expansion of space. Other commonly believed consequences of this

### The Expansion of Space: Free Particle Motion and the Cosmological Redshift

The meaning of the expansion of the universe, or the `expansion of space,' is explored using two phenomena: the motion of a test particle against a homogeneous background and the cosmological

### Solutions to the tethered galaxy problem in an expanding universe and the observation of receding blueshifted objects

• Physics
American Journal of Physics
• 2003
We use the dynamics of a galaxy, set up initially at a constant proper distance from an observer, to derive and illustrate two counter-intuitive general relativistic results. Although the galaxy does

### A direct consequence of the Expansion of Space

Consider radar ranging of a distant galaxy in a Friedman-Lemaitre cosmological model. In this model the comoving coordinate of the galaxy is constant; hence, the equations of null geodesics for

### Expanding Confusion: Common Misconceptions of Cosmological Horizons and the Superluminal Expansion of the Universe

• Physics
Publications of the Astronomical Society of Australia
• 2004
Abstract We use standard general relativity to illustrate and clarify several common misconceptions about the expansion of the universe. To show the abundance of these misconceptions we cite numerous

### Evolution of gravitational orbits in the expanding universe

• Physics
• 2007
The gravitational action of the smooth energy-matter components filling in the universe can affect the orbit of a planetary system. Changes are related to the acceleration of the cosmological scale

### A Newtonian Expanding Universe

1. The phenomenon of the expansion of the universe has usually been discussed by students of relativity by means of the concept of ‘expanding space’. This concept, though mathematically significant,

### Superluminal recession velocities

• Physics
• 2001
Hubble’s Law, v=HD (recession velocity is proportional to distance), is a theoretical result derived from the Friedmann-Robertson-Walker metric. v=HD applies at least as far as the particle horizon

### The Influence of the Cosmological Expansion on Local Systems

• Physics
• 1998
Following renewed interest, the problem of whether the cosmological expansion affects the dynamics of local systems is reconsidered. The cosmological correction to the equations of motion in the

### Joining the Hubble flow: implications for expanding space

• Physics
• 2006
The concept of expanding space has come under fire recently as being inadequate and even misleading in describing the motion of test particles in the universe. Previous investigations have suffered