We reexamine and further develop different gravito-electromagnetic analogies found in the
literature, and clarify the connection between them. Special emphasis is placed in two exact …

The Schwarzschild solution has played a fundamental conceptual role in general relativity,
and beyond, for instance, regarding event horizons, spacetime singularities and aspects of …

Given two observers, we define the “relative velocity” of one observer with respect to the
other in four different ways. All four definitions are given intrinsically, ie independently of any …

Explicit Fermi coordinates are given for geodesic observers comoving with the Hubble flow
in expanding Robertson–Walker space–times, along with exact expressions for the metric …

The Lorentz boost entails the relative velocity to be ternary. Ternary relative velocity is a
velocity of a body with respect to an interior observer as seen by a exterior-observer. Lorentz …

The curvature invariants have been the subject of interest due to the debate concerning the
notions of intrinsic/extrinsic frame dragging, the use of the electromagnetic analogy in such …

Teaching cosmology at the undergraduate or high school level requires simplifications and
analogies, and inevitably brings the teacher into contact with at least one of the pedagogical …

We analyzed two types of relativistic simultaneity associated to an observer: the spacelike
simultaneity, given by Landau submanifolds, and the lightlike simultaneity given by past …

We consider a spacetime with empty Schwarzschild-de Sitter exterior and Schwarzschild-de
Sitter interior metric for a spherical fluid with constant density. The fluid interior may be taken …

The expansion of space, and other geometric properties of cosmological models, can be
studied using geometrically defined notions of relative velocity. In this paper, we consider …