Use of Redshifts as Evidence of Dark Energy

The large-scale dynamics of the universe is generally described in terms of the time-dependent scale factor <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>a</mi><mo>(</mo><m...

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Main Author: Jan Stenflo
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Physics
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Online Access:https://www.mdpi.com/2624-8174/7/2/23
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author Jan Stenflo
author_facet Jan Stenflo
author_sort Jan Stenflo
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description The large-scale dynamics of the universe is generally described in terms of the time-dependent scale factor <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>a</mi><mo>(</mo><mi>t</mi><mo>)</mo></mrow></semantics></math></inline-formula>. To make contact with observational data, the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>a</mi><mo>(</mo><mi>t</mi><mo>)</mo></mrow></semantics></math></inline-formula> function needs to be related to the observable <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>z</mi><mo>(</mo><mi>r</mi><mo>)</mo></mrow></semantics></math></inline-formula> function, redshift versus distance. Model fitting of data has shown that the equation that governs <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>z</mi><mo>(</mo><mi>r</mi><mo>)</mo></mrow></semantics></math></inline-formula> needs to contain a constant term, which has been identified as Einstein’s cosmological constant. Here, it is shown that the required constant term is not a cosmological constant but is due to an overlooked geometric difference between proper time <i>t</i> and look-back time <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>t</mi><mi>lb</mi></msub></semantics></math></inline-formula> along lines of sight, which fan out isotropically in all directions of the 3D (3-dimensional) space that constitutes the observable universe. The constant term is needed to satisfy the requirement of spatial isotropy in the local limit. Its magnitude is independent of the epoch in which the observer lives and agrees with the value found by model fitting of observational data. Two of the observational consequences of this explanation are examined: an increase in the age of the universe from 13.8 Gyr to 15.4 Gyr, and a resolution of the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>H</mi><mn>0</mn></msub></semantics></math></inline-formula> tension, which restores consistency to cosmological theory.
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spelling doaj-art-6745864781fd4a7b8b6a8a75581272dd2025-08-20T02:21:57ZengMDPI AGPhysics2624-81742025-06-01722310.3390/physics7020023Use of Redshifts as Evidence of Dark EnergyJan Stenflo0Institute for Particle Physics and Astrophysics, ETH (Eidgenössische Technische Hochschule) Zurich, CH-8093 Zurich, SwitzerlandThe large-scale dynamics of the universe is generally described in terms of the time-dependent scale factor <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>a</mi><mo>(</mo><mi>t</mi><mo>)</mo></mrow></semantics></math></inline-formula>. To make contact with observational data, the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>a</mi><mo>(</mo><mi>t</mi><mo>)</mo></mrow></semantics></math></inline-formula> function needs to be related to the observable <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>z</mi><mo>(</mo><mi>r</mi><mo>)</mo></mrow></semantics></math></inline-formula> function, redshift versus distance. Model fitting of data has shown that the equation that governs <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>z</mi><mo>(</mo><mi>r</mi><mo>)</mo></mrow></semantics></math></inline-formula> needs to contain a constant term, which has been identified as Einstein’s cosmological constant. Here, it is shown that the required constant term is not a cosmological constant but is due to an overlooked geometric difference between proper time <i>t</i> and look-back time <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>t</mi><mi>lb</mi></msub></semantics></math></inline-formula> along lines of sight, which fan out isotropically in all directions of the 3D (3-dimensional) space that constitutes the observable universe. The constant term is needed to satisfy the requirement of spatial isotropy in the local limit. Its magnitude is independent of the epoch in which the observer lives and agrees with the value found by model fitting of observational data. Two of the observational consequences of this explanation are examined: an increase in the age of the universe from 13.8 Gyr to 15.4 Gyr, and a resolution of the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>H</mi><mn>0</mn></msub></semantics></math></inline-formula> tension, which restores consistency to cosmological theory.https://www.mdpi.com/2624-8174/7/2/23cosmological constantcosmological modelsaccelerating universestellar ages
spellingShingle Jan Stenflo
Use of Redshifts as Evidence of Dark Energy
Physics
cosmological constant
cosmological models
accelerating universe
stellar ages
title Use of Redshifts as Evidence of Dark Energy
title_full Use of Redshifts as Evidence of Dark Energy
title_fullStr Use of Redshifts as Evidence of Dark Energy
title_full_unstemmed Use of Redshifts as Evidence of Dark Energy
title_short Use of Redshifts as Evidence of Dark Energy
title_sort use of redshifts as evidence of dark energy
topic cosmological constant
cosmological models
accelerating universe
stellar ages
url https://www.mdpi.com/2624-8174/7/2/23
work_keys_str_mv AT janstenflo useofredshiftsasevidenceofdarkenergy