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Globular clusters (GCs) in the Milky Way have characteristic velocity dispersions that are consistent with the predictions of Newtonian gravity, and may be at odds with Modified Newtonian Dynamics (MOND). We discuss a modified gravity (MOG)…

Astrophysics · Physics 2008-06-14 J. W. Moffat , V. T. Toth

The accelerating expansion of the universe is the most surprising cosmological discovery in many decades. In this short review, we briefly summarize theories for the origin of cosmic acceleration and the observational methods being used to…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-03 Michael J. Mortonson , David H. Weinberg , Martin White

Wide binary stars are used to test the modified gravity called Scalar-Tensor-Vector Gravity or MOG. This theory is based on the additional gravitational degrees of freedom, the scalar field $G=G_N(1+\alpha)$, where $G_N$ is Newton's…

General Relativity and Quantum Cosmology · Physics 2024-05-31 John W. Moffat

Cosmology is very exciting for three reasons. There is a very successful standard model - the hot big bang - which describes the evolution of the Universe from 10^{-2} sec onward. There are bold ideas, foremost among them are inflation and…

Astrophysics · Physics 2016-02-09 Michael S. Turner

We consider structure formation and CMB anisotropies in a closed universe, both with and without a cosmological constant. The CMB angular power spectrum and the matter transfer function are presented, along with a discussion of their…

Astrophysics · Physics 2009-08-18 Martin White , Douglas Scott

Increasing improvements in the independent determinations of the Hubble constant and the age of the universe now seem to indicate that we need a small non-vanishing cosmological constant to make the two independent observations consistent…

High Energy Physics - Phenomenology · Physics 2009-10-28 Anupam Singh

The dark energy-cold dark matter paradigm ($\Lambda$CDM) has gained widespread acceptance because it explains the pattern of anisotropies observed in the cosmic microwave background radiation, the observed distribution of large scale…

Astrophysics of Galaxies · Physics 2019-12-03 Robert H. Sanders

We study cosmology in a class of minimally modified gravity (MMG) with two local gravitational degrees of freedom. We classify modified gravity theories into type-I and type-II: theories of type-I have an Einstein frame and can be recast by…

General Relativity and Quantum Cosmology · Physics 2019-01-16 Katsuki Aoki , Antonio De Felice , Chunshan Lin , Shinji Mukohyama , Michele Oliosi

Cosmic growth of large scale structure probes the entire history of cosmic expansion and gravitational coupling. To get a clear picture of the effects of modification of gravity we consider a deviation in the coupling strength (effective…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-19 Mikhail Denissenya , Eric V. Linder

The cosmological constant problem represents a profound conflict between quantum field theory and general relativity. Unimodular gravity offers a compelling starting point by de-gravitating the vacuum energy of the Standard Model, but this…

High Energy Physics - Phenomenology · Physics 2025-11-18 David E. Kaplan , Surjeet Rajendran

The shadows cast by non-rotating and rotating modified gravity (MOG) black holes are determined by the two parameters mass $M$ and angular momentum $J=Ma$. The sizes of the shadows cast by the spherically symmetric static Schwarzschild-MOG…

General Relativity and Quantum Cosmology · Physics 2015-03-26 J. W. Moffat

We consider some nonlinear effects of gravity in cosmology. Possible physically interesting consequences include: non-requirement of dark matter and dark energy, asymmetric gravitational matter-creation, emergent homogeneity/isotropy &…

General Physics · Physics 2018-05-29 Johan Hansson , Jaime Dols Duxans , Martin Svensson

We find that current Cosmic Microwave Background (CMB) anisotropy data strongly constrain the mean spatial curvature of the Universe to be near zero, or, equivalently, the total energy density to be near critical-as predicted by inflation.…

Astrophysics · Physics 2009-10-31 S. Dodelson , L. Knox

Since it can describe the rotation curves of galaxies without dark matter and can give rise to accelerated expansion, conformal gravity attracts much attention recently. As a theory of modified gravity, it is important to test conformal…

General Relativity and Quantum Cosmology · Physics 2014-05-28 Rong-Jia Yang , Bohai Chen , Haijun Zhao , Jun Li , Yuan Liu

We use data from observational cosmology to put constraints on higher-dimensional extensions of general relativity in which the effective four-dimensional dark-energy density (or cosmological "constant") decays with time. In particular we…

Astrophysics · Physics 2009-11-13 J. M. Overduin , P. S. Wesson , B. Mashhoon

We propose a modification of Einstein-Cartan gravity equations. The modified cosmology departs from the standard model of cosmology for small Hubble parameter. A characteristic Hubble scale h0, which is intrinsically related to cosmological…

General Relativity and Quantum Cosmology · Physics 2015-07-21 Wei Lu

We apply the new dynamics of 3-space to cosmology by deriving a Hubble expansion solution. This dynamics involves two constants; G and alpha - the fine structure constant. This solution gives an excellent parameter-free fit to the recent…

General Physics · Physics 2007-06-27 Reginald T Cahill

A modified gravity (MOG) possesses a light, neutral vector particle called a ``phion'' associated with a vector field $\phi^\mu$, which forms a cold fluid of Bose-Einstein condensates before recombination with zero pressure and zero shear…

Astrophysics · Physics 2007-05-23 J. W. Moffat

Most of the calculations done to obtain the value of the cosmological constant use methods of quantum gravity, a theory that has not been established as yet, and a variety of results are usually obtained. The numerical value of the…

Astrophysics · Physics 2007-05-23 Moshe Carmeli

A nonvanishing cosmological term in Einstein's equations implies a nonvanishing spacetime curvature even in absence of any kind of matter. It would, in consequence, affect many of the underlying kinematic tenets of physical theory. The…

General Relativity and Quantum Cosmology · Physics 2009-11-10 R. Aldrovandi , J. P. Beltran Almeida , J. G. Pereira
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