Does the Cosmological Expansion Change Local Dynamics?
It is a well-known fact that the Newtonian description of dynamics within Galaxies for its known matter content is in disagreement with the observations as the acceleration approaches <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline">&l...
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| Format: | Article |
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MDPI AG
2021-08-01
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| Series: | Symmetry |
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| Online Access: | https://www.mdpi.com/2073-8994/13/8/1417 |
| _version_ | 1797522008377917440 |
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| author | Marcelo Schiffer |
| author_facet | Marcelo Schiffer |
| author_sort | Marcelo Schiffer |
| collection | DOAJ |
| description | It is a well-known fact that the Newtonian description of dynamics within Galaxies for its known matter content is in disagreement with the observations as the acceleration approaches <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>a</mi><mn>0</mn></msub><mo>≈</mo><mn>1.2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>10</mn></mrow></msup></mrow></semantics></math></inline-formula> m/s<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula> (slighter larger for clusters). Both the Dark Matter scenario and Modified Gravity Theories (MGT) fail to explain the existence of such an acceleration scale. Motivated by the closeness of the acceleration scale and the Hubble constant <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>c</mi><msub><mi>H</mi><mn>0</mn></msub><mo>≈</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>9</mn></mrow></msup></mrow></semantics></math></inline-formula> h m/s<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula>, we are led to analyze whether this coincidence might have a Cosmological origin for scalar-tensor and spinor-tensor theories by performing detailed calculations for perturbations that represent the local matter distribution on the top of the cosmological background. Then, we solve the field equations for these perturbations in a power series in the present value of the Hubble constant. As we shall see, for both theories, the power expansion contains only even powers in the Hubble constant, a fact that renders the cosmological expansion irrelevant for the local dynamics. |
| first_indexed | 2024-03-10T08:20:32Z |
| format | Article |
| id | doaj.art-78cd08c64f194b718120078f9562de36 |
| institution | Directory Open Access Journal |
| issn | 2073-8994 |
| language | English |
| last_indexed | 2024-03-10T08:20:32Z |
| publishDate | 2021-08-01 |
| publisher | MDPI AG |
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| series | Symmetry |
| spelling | doaj.art-78cd08c64f194b718120078f9562de362023-11-22T10:01:08ZengMDPI AGSymmetry2073-89942021-08-01138141710.3390/sym13081417Does the Cosmological Expansion Change Local Dynamics?Marcelo Schiffer0Physics Department, Ariel University, Ariel 40700, IsraelIt is a well-known fact that the Newtonian description of dynamics within Galaxies for its known matter content is in disagreement with the observations as the acceleration approaches <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>a</mi><mn>0</mn></msub><mo>≈</mo><mn>1.2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>10</mn></mrow></msup></mrow></semantics></math></inline-formula> m/s<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula> (slighter larger for clusters). Both the Dark Matter scenario and Modified Gravity Theories (MGT) fail to explain the existence of such an acceleration scale. Motivated by the closeness of the acceleration scale and the Hubble constant <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>c</mi><msub><mi>H</mi><mn>0</mn></msub><mo>≈</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>9</mn></mrow></msup></mrow></semantics></math></inline-formula> h m/s<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula>, we are led to analyze whether this coincidence might have a Cosmological origin for scalar-tensor and spinor-tensor theories by performing detailed calculations for perturbations that represent the local matter distribution on the top of the cosmological background. Then, we solve the field equations for these perturbations in a power series in the present value of the Hubble constant. As we shall see, for both theories, the power expansion contains only even powers in the Hubble constant, a fact that renders the cosmological expansion irrelevant for the local dynamics.https://www.mdpi.com/2073-8994/13/8/1417cosmological expansionGalactic dynamicsalternatives to dark matter |
| spellingShingle | Marcelo Schiffer Does the Cosmological Expansion Change Local Dynamics? Symmetry cosmological expansion Galactic dynamics alternatives to dark matter |
| title | Does the Cosmological Expansion Change Local Dynamics? |
| title_full | Does the Cosmological Expansion Change Local Dynamics? |
| title_fullStr | Does the Cosmological Expansion Change Local Dynamics? |
| title_full_unstemmed | Does the Cosmological Expansion Change Local Dynamics? |
| title_short | Does the Cosmological Expansion Change Local Dynamics? |
| title_sort | does the cosmological expansion change local dynamics |
| topic | cosmological expansion Galactic dynamics alternatives to dark matter |
| url | https://www.mdpi.com/2073-8994/13/8/1417 |
| work_keys_str_mv | AT marceloschiffer doesthecosmologicalexpansionchangelocaldynamics |