Visar inlägg med etikett redshift. Visa alla inlägg
Visar inlägg med etikett redshift. Visa alla inlägg

fredag 19 maj 2023

Do Galaxies Recede at a Speed larger than the Speed of Light?

Maximally observed redshift  z=8.

The light from far away galaxies receding from us with a speed $v$ is received with a redshift frequency factor given by the Doppler effect formula with the speed of light normalised to 1: 

  • $f=\frac{1}{1+v}$
or in alternative common notation
  • $1+z=\frac{1}{f}$
with $z=v$. This is a consequence of Maxwell's equations in a Euclidean space coordinate system fixed to Earth in accordance with the cosmological model of Many-Minds Relativity. There is no compelling reason to reject Maxwell's equations as a correct model of the propagation of light. There is no compelling reason to invoke any coordinate system moving with respect to Earth since observations are made on Earth not in receding galaxies. Since thus only one coordinate system is used, Einstein's special theory of relativity with objective to coordinate observations in different coordinate systems according to the Lorentz transformation, does not appear to have anything to offer.  

The largest observed redshift is about $z=8$ (see above figure) indicating a recession speed 8 times larger than the speed of light. Observations thus indicate an expansion speed of the Universe which is much larger than the speed of light. This seems to be in contradiction with Einstein's basic postulate of the speed of light in vacuum as maximal speed of both light and matter.  

In short, no real physics appears to prevent the Universe from expanding faster than the speed of light, and  this is what in fact is observed. This puts a big question mark to Einstein's basic postulate. 

Since light governed by Maxwell's equations does not seem to interact with Newton's mechanics for the motion of material bodies (explored in more detail in Many-Minds Relativity), there is no reason to expect that the speed of light sets a limit to the possible recession speed of material bodies. In Leibnizian terms, there is no sufficient reason for something like that to be true. In addition, observations show recession speeds much larger than the speed of light. Your conclusion?

lördag 28 september 2019

Redshift in SR vs MMR



Recent posts have given evidence that Einstein's special theory of relativity SR is the result of an incorrect contradictory derivation of the Lorentz transformation from the basic physical Postulate of SR, and thus is unphysical. An alternative theory based on the same Postulate using correct logic takes the form of Many-Minds Relativity MMR.

In MMR a light source is connected to a receiver of light by a standing wave satisfying Maxwell's equations in a space-time system with the space axis connecting source to receiver. Shifting amplitude and frequency of the light source will then travel as a disturbance superimposed on the standing wave to be received at the receiver with a time delay given by the speed of light and the distance between source and receiver, and Doppler shift from motion of the source. The description of light in MMR is not as a stream of "photons" as "particles of light", which is unphysical.

Since both SR and MMR differ from Newtonian theory only for very high velocities, it is natural to compare predictions of SR and MMR with observations of large cosmological redshifts $z$ from far away galaxies receding from an observer on the Earth with very high velocity $v$.

According to SR the redshift $z$ is connected to the recession speed $v$ by the formula (with the speed of light = 1):
  • $z = \sqrt{\frac{1 + v}{1 − v}}-1$ where $-1\lt v\lt 1$.  
According to Peacock Cosmological Physics p. 72, this is misleading and any such temptation should be avoided. I agree: SR is unphysical and so must a SR redshift be. In particular SR does not allow a recession speed larger than the speed of light.

The accepted way to connect the redshift to the recession velocity is thus not according to SR, but instead by invoking Einstein's general theory of relativity GR to come up with the idea that it is the very "fabric of space" between source and receiver which "stretches" (see picture above) and not really the source that speeds away, which allows recession speeds larger than the speed of light with redshifts bigger than 1. This is referred to cosmological redshift connected with observations of redshifts as large as $z=8$.

In MMR we have (without taking into account the time of travel of a light signal):
  •  $1+z = \frac{\lambda_r}{\lambda_s}$ with $z=v$,    
where $\lambda_s$ is the wave-length of the light emitted by the galaxy source and $\lambda_r$ that observed. This is the same as the classical Doppler shift formula, where the increase of wave-length and redshift depends on the motion of the source vs the receiver.  

But MMR is also compatible with the idea of "stretching of space" as simply a different space axis in the same Maxwell's equations with a speed of light = 1 underlying MMR. The observed large cosmological redshifts of far away galaxies thus appear to be compatible with MMR, but not SR.

Note also that it is not natural to invoke GR concerned with gravitation, to handle propagation of light, which is the specialty of special relativity.