Related papers: V\'enus selon Ibn al-Shatir
This article investigates long-term orbits within the Earth's magnetosphere, specifically focusing on orbits where the argument of periapsis is synchronized with changes induced by lunar gravity assists and the Earth's argument of latitude…
We show how the correction to the calculation of the mass in the original relativistic model of a rotating star by Hartle [6], found recently [10], appears in the Newtonian limit, and that the correcting term is indeed present, albeit…
On November 18, 1915 Einstein reported to the Prussian Academy that the perihelion motion of Mercury is explained by his new General Theory of Relativity: Einstein found approximate solutions to his November 11, 1915 field equations.…
The Hittite city Sarissa was founded in the 16th century BC and has been systematically constructed. The city gates and the bigger public buildings were arranged at about 45{\deg} relative to the cardinal directions. However, one of the…
Numerical relativity is an essential tool for solving Einstein's equations of general relativity for dynamical systems characterized by high velocities and strong gravitational fields. The implementation of new algorithms that can solve…
The calculation of the trajectories in the Sun-Earth-Mars system will be performed in two different models, both in the framework of Newtonian mechanics. First model is well-known Copernican system, which assumes the Sun is at rest and all…
We express the position of the Sun in the sky as a function of time and the observer's geographic coordinates. Our method is based on applying rotation matrices to vectors describing points on the celestial sphere. We also derive direct…
The icy moons are in the focus of the exploration plans of the leading space agencies because of the indications of water-based life and geological activity observed in a number of these objects. In particular, the presence of geyser-like…
General Relativity (GR) quantitatively accounts for the anomalous perihelion precession observed in several planets' orbits, with Mercury exhibiting the most significant deviation from Newtonian predictions. In the present work, I carry out…
This document is the EnVision Venus orbiter proposal, submitted in October 2016 in response to ESA's M5 call for Medium-size missions for its Science Programme, for launch in 2029. Why are the terrestrial planets so different? Venus should…
We have tested the appropriateness of two-soliton analytic metric to describe the exterior of all types of neutron stars, no matter what their equation of state or rotation rate is. The particular analytic solution of the vaccuum Einstein…
The purpose of the work is to furnish a complete study of a discrete and special function, discovered by the author and named with the Arabian letter "SHIN" {The letter SHIN is the thirteenth letter of the Arabian alphabet}. It includes…
Stellar systems - star clusters, galaxies, dark matter haloes, and so on - are ubiquitous characters in the evolutionary tale of our Universe. This tutorial article is an introduction to the collective dynamical evolution of the very large…
I describe how to obtain a rather good experimental determination of the eccentricity of the Earth orbit, as well as the obliquity of the Earth rotation axis, by measuring, over the course of a year, the elevation of the Sun as a function…
It is customary to employ a semi-spherical scale model to describe the apparent path of the Sun across the sky, whether it be its diurnal motion or its variation throughout the year. A flat surface and three bent semi-rigid wires…
The kinematics of the Solar zenith passage on the Earth was shown as a simple harmonic motion. This analytical model used the uniform circular motion to describe the Earth's rotation relative to its axis and relative to the Sun, also this…
We perform fully relativistic calculations of binary neutron stars in corotating, circular orbit. While Newtonian gravity allows for a strict equilibrium, a relativistic binary system emits gravitational radiation, causing the system to…
Synchronous satellites of Venus have long been thought unstable, but we use Poincare's surface of section technique to show that synchronous quasi-satellites orbiting just outside Venus' Hill sphere are quite stable, at least for centuries.…
A trajectory isomorphism between the two Newtonian fixed center problem in the sphere and two associated planar two fixed center problems is constructed by performing two simultaneous gnomonic projections in $S^2$. This isomorphism converts…
$f(R)$ theories of gravity are one of the most popular alternative explanations for dark energy and therefore studying the possible astrophysical implications of these theories is an important task. In the present paper we make a…