Preprint (05.10.2002)
Date: Sat, 05 Oct 2002 16:22:18 GMT
From: redshift0@narod.ru (Alex Chepick)
Organization:  
Newsgroups: sci.physics, sci.astro
Subject: Doppler Effect Against Scale-Factor

Key words:  Doppler effect scale-factor expanding universe Hubble constant

 

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The formula of Doppler effect does not fit for definition of a Hubble constant

Alex M. Chepick, Nizhni Novgorod
05.10.2002

 

Abstract

The impossibility of usage of the Doppler effect's relativistic formula for definition of a Hubble constant in the expanding Universe is demonstrated most shortly and simply.

 

1.      Introduction

 

When Hubble inferred his famous law v=HD, he with clean conscience has used the relativistic formula of Doppler effect for definition of a radial velocity v of object:

 

(z+1)2= (z +v)/(cv) (1)

 

where z is redshift, c - speed of light.

 

2.      Role of the formula of Doppler in definition of the Hubble constant

 

Many methods of definition of the Hubble constant have appeared since then, but for the Static Universe the definition of a radial velocity of objects and distance up to it lies in the basis of the most of it. The methods of definition of distance D can be miscellaneous. But the radial velocity v is determining only under the relativistic formula of Doppler effect (1) or by its approaching for low speeds: v = cz.

 

For models of the expanding Universe the methods of definition of Hubble parameter are based in the majority on the formula H(t)=a'(t)/a(t), where a(t) is time-depending scale factor.

 

And as the formula of Doppler is deduced for static Universe and is tested only in it, then it is impossible to apply this formula in expanding Universe.

 

Really, let for some source of light we have measured redshift z. Guessing applicability of the formula (1) we determine speed v of moving of this object in our system of reference: v=(2z+z2)/(2+2z+z2). Then under relativity theory the pace of time in a system of reference of the source grater in (1(v/c)2)-1/2 of times than pace of time in our system of reference. But under the theory of expanding Universe the pace of time in a system of reference of this source grater in (z+1) times concerning pace of time in our system of reference. [1]

Compare two expressions for pace of time:

 

(1(v/c)2)-1/2 = (z+1) (2)

 

We obtain with the help of the formula (1), the equality (2) is executed only at z=0, v=0.

 

3.      Conclusions

 

1. The formula of Doppler effect deduced for the static Universe, it is defaulted in the expanding Universe.

2. The formula of Doppler effect in the expanding Universe should in addition depend on time of radiation, reception time and scale factor.

 

Reference:

 

1.                  Postnov K.A. Lectures on Astrophysics for Students of MSU

[http://info.phys.msu.su/AstroPhysic/Lecture5/html/lecture5.html]

2.                  Sten Odenwald and Rick Fienberg Galaxy Redshifts Reconsidered

[http://www2.ari.net/home/odenwald/anthol/expan.html]

( I can E-mail You this article. Reference was taken at address: [http://ursa.irk.ru/cosmo/part2dl.html])

 

 

 

Email:redshift0@narod.ru

 

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Last correction 22.11.2002 22:18

 

 

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