相关论文: Babylonian and Indian Astronomy: Early Connections

This article provides information about the factors that necessitated the need to adjust the calendar during the time of Umar Khayyam, the method of choosing the beginning of the year, and the length of the months. It also attempts to…

About half of all known stellar systems with Sun-like stars consist of two or more stars, significantly affecting the orbital stability of any planet in these systems. This observational evidence has prompted a large array of theoretical…

The difference in formation process between binary stars and planetary systems is reflected in their composition as well as their orbital architecture, particularly orbital eccentricity as a function of orbital period. It is suggested here…

It has been known for some time that the Milky Way is a barred disk galaxy. More recently several studies inferred from starcount observations that the Galaxy must contain a separate, new, flat long bar component, twisted relative to the…

For its beautiful rings, active atmosphere and mysterious magnetic field, Saturn is a fascinating planet. It also holds some of the keys to understanding the formation of our Solar System and the evolution of giant planets in general. While…

Studying star formation in spiral arms tells us not only about the evolution of star formation, and molecular clouds, but can also tell us about the nature of spiral structure in galaxies. I will address both these topics using the results…

The use of the observed positions of celestial bodies to determine the location of a navigator and to direct vessels, was an aspiration of ancient seafarers. Various peoples, in the Mediterranean as much as in the Indian Ocean, in China as…

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…

With more and more extrasolar planets discovered in and around binary star systems, questions concerning the determination of the classical Habitable Zone arise. Do the radiative and gravitational perturbations of the second star influence…

We investigate numerically complex dynamical systems where a fixed point is surrounded by a disk or ball of quasiperiodic orbits, where there is a change of variables (or conjugacy) that converts the system into a linear map. We compute…

The stone alignment 'Nilurallu' at Murardoddi is a megalithic monument containing standing stones of 12 to 16 feet high that are arranged somewhat in a squarish pattern. This is one of the stone alignments listed by Allchin (1956) as a…

The great conjunction of 21 December 2020 saw Jupiter and Saturn appear together in the sky, separated by just a tenth of a degree (equivalent to a distance five times smaller than the diameter of the full Moon). This provided a potential…

Callebaut et al. (2012)'s claim that Scafetta (2010)'s results about a correlation between 20-year and 60-year temperature cycles and the orbital motion of Jupiter and Saturn were not confirmed by Humlum et al. (2011) is erroneous and…

The first extrasolar planets have been detected by the measurement of the wobble of the parent star. This wobble leads to the periodic modulation of three observables: the radial velocity, the position on the sky and the time of arrival of…

The Galactic disk retains a vast amount of information about how it came to be, and how it evolved over cosmic time. However, we know very little about the secular processes associated with disk evolution. One major uncertainty is the…

Cepheid stars are crucial objects for a variety of topics that range from stellar pulsation and the evolution of intermediate-mass stars to the understanding the structure of the Galaxy and the Universe through the distance measurements…

Satellites of asteroids have been discovered in nearly every known small body population, and a remarkable aspect of the known satellites is the diversity of their properties. They tell a story of vast differences in formation and evolution…

It is widely believed that the advance of science in the Islamic world after the mid-fifteenth century A.D. suffered a decline. For the purpose of examining this belief, a manuscript by Qasim ali al-Qayini (ca. A.D.1685) was chosen based on…

One well-tested method in science is to separate the object of interest from its surroundings and look at it in isolation. The advantage is that unimportant information is removed and the true properties of the object are seen more clearly.…

In the coming years, it is likely that the first potentially Earth-like planets will be discovered orbiting other stars. Once found, the characterisation of those planets will play a vital role in determining which will be chosen as the…