@article {Nahum:2015:0836-1398:167,
title = "A theoretical demonstration that the cosmological constant must be null and the universe expansion speed is constant",
journal = "Physics Essays",
parent_itemid = "infobike://pe/pe",
publishercode ="pe",
year = "2015",
volume = "28",
number = "2",
publication date ="2015-06-18T00:00:00",
pages = "167-170",
itemtype = "ARTICLE",
issn = "0836-1398",
eissn = "2371-2236",
url = "https://www.ingentaconnect.com/content/pe/pe/2015/00000028/00000002/art00004",
doi = "doi:10.4006/0836-1398-28.2.167",
keyword = "Cosmological Parameters, Cosmological Constant, Relativity, Gravitation, Early Universe, Hubble Constant",
author = "Nahum, Lucio",
abstract = "In a previous paper, it was demonstrated that, if the expansion speed of the universe has not to exceed the limit of light speed c, respecting at the same time the Hubble law and the density isotropy of the universe, the mass of the universe must increase linearly with the universe
radius. Using a Newtonian approach, it was demonstrated that a consequence of this proportionality was the absence of gravity in the expansion process, therefore, a cosmological constant could not be necessary. Another consequence of the linear increase of the mass with the radius was that
the pressure p in the energy conservation equation was p = -
c 2 / 3 , where is the density. Introducing this value of the pressure in the Friedmann equations, the same results as in the Newtonian approach were obtained (i.e., a null gravitation during expansion
and the same density variation with time). In the present study, it is mathematically demonstrated that a cosmological constant cannot be but zero. It is also demonstrated that the universe mass must vary with time even if the expansion speed of the universe were not constant. It is evidenced
that the expansion speed of the universe cannot however vary with time and that the mass increase is a necessary condition for the compatibility of relativity with the Hubble law and the energy conservation principle.",
}