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Importantly, the theory also explains (without invoking the existence of dark matter and tweaking of its new free parameters) why galactic rotation curves differ from the profile expected with visible matter. The theory of entropic gravity posits that what has been interpreted as unobserved dark matter is the product of quantum effects that can ...
Induced gravity (or emergent gravity) is an idea in quantum gravity that spacetime curvature and its dynamics emerge as a mean field approximation of underlying microscopic degrees of freedom, similar to the fluid mechanics approximation of Bose–Einstein condensates. The concept was originally proposed by Andrei Sakharov in 1967.
In physics, gravity (from Latin gravitas 'weight' [1]) is a fundamental interaction primarily observed as a mutual attraction between all things that have mass.Gravity is, by far, the weakest of the four fundamental interactions, approximately 10 38 times weaker than the strong interaction, 10 36 times weaker than the electromagnetic force, and 10 29 times weaker than the weak interaction.
Gravity field surrounding Earth from a macroscopic perspective. Newton's law of universal gravitation can be written as a vector equation to account for the direction of the gravitational force as well as its magnitude. In this formula, quantities in bold represent vectors.
Examples of emergent laws are the second law of thermodynamics and the theory of natural selection. The advocates of emergence argue that emergent laws, especially those describing complex or living systems are independent of the low-level, microscopic laws. In this view, emergent laws are as fundamental as a theory of everything.
He further argues that this entropy modifies emergent gravity, introducing residual forces when the acceleration due to gravity is very weak. [14] The result provides a candidate explanation for dark matter similar to the Modified Newtonian Dynamics (MOND) proposal and explains the empirical relationship between dark matter and the Hubble constant.
What this means is addressed in the following three sections, which explore the motion of so-called test particles, examine which properties of matter serve as a source for gravity, and, finally, introduce Einstein's equations, which relate these matter properties to the curvature of spacetime.
General relativity generalizes special relativity (which explains motion at constant speed) and refines Newton's law of universal gravitation, which define gravity as a force, providing a unified description of gravity as a geometric property of space and time, or four-dimensional spacetime.