ΛCDM has recently assumed the role of a new Cosmological Standard Model giving a coherent picture of the today observed universe . Although being the best fit to a wide range of data, it suffers of several theoretical shortcomings  so it fails in tracking cosmic dynamics at every redshift and fails in according observational cosmology to some fundamental theory of
physical interactions. Among the defects of this model, there is the lack of final probes, at fundamental level, for dark energy and dark matter candidates (which should be the 95% of the energy-matter content of the universe!) which frustrates the possibility to reduce ΛCDM to some self-consistent scheme, despite of the fact that it is a fair ”snapshot” of the present status of the universe. These facts motivate the search for other models, among which alternative theories of gravity that should reproduce the successes of ΛCDM but should be more appropriate in describing the cosmological dynamics [3, 4].
In particular, the large part of dark energy models relies on the implicit assumption that Einstein’s General Relativity (GR) is the correct theory of gravity indeed. Nevertheless, its validity on large astrophysical and cosmological scales has never been tested but only assumed , and it is therefore conceivable that both cosmic speed up and missing matter, respectively the dark energy and the dark matter, are nothing else but signals of a breakdown of GR at large scales.
...what are some supposed cosmological alternatives to dark energy and dark matter?
According to CMB measurements, dark matter/baryonic matter only make up 30 percent of the critical density. So dark energy supposedly makes up the other 70 percent for a flat, homogeneous, isotropic universe; and isn't there evidence that dark energy is found in supervoids and superclusters? What does the VMH say about this?
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