Observations of General Relativity at strong and weak limits

Abstract

Einstein's General Relativity theory has been tested in many ways during the last hundred years as reviewed in this chapter. Two tests are discussed in detail in this article: the concept of a zero gravity surface, the roots of which go back to Järnefelt, Einstein and Straus, and the no-hair theorem of black holes, first proposed by Israel, Carter and Hawking. The former tests the necessity of the cosmological constant Λ, the latter the concept of a spinning black hole. The zero gravity surface is manifested most prominently in the motions of dwarf galaxies around the Local Group of galaxies. The no-hair theorem is testable for the first time in the binary black hole system OJ287. These represent stringent tests at the limit of weak and strong gravitational fields, respectively. In this article we discuss the current observational situation and future possibilities.

The Hubble diagram for a system within dark energy: influence of some relevant quantities

“…Thus Chernin et al (2009) used the relative velocity and distance of our Galaxy and the M 31 galaxy together with the outflow data to derive the local DE density as ρ loc /ρ Λ = 0.8−3.8. Using a similar approach, Byrd et al (2014) revised this range to ρ loc /ρ Λ ≈ 0.5−2.5.…”

“…Our starting point is the outflow model (Chernin 2001;Chernin et al 2006;Byrd et al 2012) intended to describe the major features of expansion flows around local masses, which was motivated by the observed picture of the Local Group with outflowing dwarf galaxies around it (e.g., van den Bergh 1999; Karachentsev et al 2009). The model treats the dwarfs as "test particles" moving in the force field produced by the gravitating mass of the group and the possible DE background.…”

“…A gravitationally bound group is located within its zero-gravity sphere having the radius R = R ZG (Chernin 2001):…”

“…It is therefore desirable to consider different methods together in order to lower systematic and random errors (Chernin et al 2009;Byrd et al 2014). …”

A graph of dark energy significance on different spatial and mass scales

“…According to the Planck Surveyor results (Planck Collaboration 2013), the global density of the DE is, in round numbers, ρ Λ ≈ 6 × 10 −30 g cm −3 . 1 Because of the non-uniform distribution of gravitating matter, the cosmic antigravity can be stronger than gravity also locally on scales of ∼ 1−10 Mpc (Chernin 2001), which in principle makes it possible to detect the DE in the local galaxy universe, as reviewed by Byrd et al (2012Byrd et al ( , 2015. For a recent study about the DE in the vicinity of the Local Group, see Saarinen & Teerikorpi (2014).…”