منابع مشابه
Is the Universe homogeneous?
The standard model of cosmology is based on the existence of homogeneous surfaces as the background arena for structure formation. Homogeneity underpins both general relativistic and modified gravity models and is central to the way in which we interpret observations of the cosmic microwave background (CMB) and the galaxy distribution. However, homogeneity cannot be directly observed in the gal...
متن کاملA Fractal Galaxy Distribution in a Homogeneous Universe?
In this letter we present an idea which reconciles a homogeneous and isotropic Friedmann universe with a fractal distribution of galaxies. We use two observational facts: The flat rotation curves of galaxies and the (still debated) fractal distribution of galaxies with fractal dimension D = 2. Our idea can also be interpreted as a redefinition of the notion of bias.
متن کاملIS THE UNIVERSE HOMOGENEOUS ? ( On Large Scales ) ∗
I critically discuss in a pedagogical and phenomenological way a few crucial tests challenging the recent claims by Pietronero and collaborators that there is no evidence from available galaxy catalogues that the Universe is actually homogeneous above a certain scale. In a series of papers, these authors assert that observations are consistent with a fractal distribution of objects extending to...
متن کاملSingularity Free (homogeneous Isotropic) Universe in Graviton-dilaton Models
We present a class of graviton-dilaton models in which a homogeneous isotropic universe, such as our observed one, evolves with no singularity at any time. Such models may stand on their own as interesting models for singularity free cosmology, and may be studied further accordingly. They may also arise from string theory. We discuss critically a few such possibilities. PACS numbers: 98.80.Hw, ...
متن کاملAn oscillating, homogeneous and isotropic Universe from Scalar-Tensor gravity
An oscillating, homogeneous and isotropic Universe which arises from Scalar-Tensor gravity is discussed in the linearized approach, showing that some observative evidences like the Hubble Law and the Cosmological Redshift are in agreement with the model. In this context Dark Energy appears like a pure curvature effect arising by the scalar field. PACS numbers: 04.80.Nn, 04.30.Nk, 04.50.+h
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ژورنال
عنوان ژورنال: Nature
سال: 1975
ISSN: 0028-0836,1476-4687
DOI: 10.1038/256169a0