scholarly journals Galaxies and Their Nuclei

1974 ◽  
Vol 3 ◽  
pp. 51-66
Author(s):  
V. A. Ambartsumian

Our Extraordinary General Assembly is devoted to the memory of one of the greatest men of science to the genial Polish astronomer - Nicolaus Copernicus. The main service of Copernicus which has made his name immortal was in finding the correct interpretation of the planetary motions we observe. Instead of geocentric notions, which proved unable to explain the accumulated bulk of empirical data on the apparent motions of planets he has put forward and advocated the notion of a solar system thus presenting the true picture of the part of the Universe we live in. The scientific revolution started by him was continued by Galileo and Kepler and was crowned with the great theoretical generalizations of Newton. As a result a foundation has been created for the most exact theories of motions in the solar system which were developed during the next centuries. These theories in their modern form give also the possibility to solve all the problems concerning the orbital motions of spaceships.At this stage we can not yet boast that in the study of nuclei of galaxies and their activity we have reached the level which existed in planetary astronomy even before the works of Newton. Only 15 years elapsed from the moment when the idea of activity of nuclei of galaxies was clearly formulated (Ambartsumian, 1958). During these years discoveries of the greatest importance have been made. New unexpected discoveries occur almost each year. These discoveries influence decisively our notions on the diversity of objects and phenomena in the distant space, but they are still insufficient for the construction of adequate theories. In order to penetrate into the very nature of nuclear phenomena we require new observations, new measurements and new data. And if some optimists imagine that the time has already ripen to build a general theory of these phenomena, the more cautious astronomers would like to consider a more or less satisfactory systematization of observational data concerning the activity of nuclei and the understanding of external physical processes accompanying it as a tremendous success.

ADALAH ◽  
2019 ◽  
Vol 3 (3) ◽  
Author(s):  
Yulia Zahra

Heliocentrism is one of the controversial theory which was found by Nicolaus Copernicus. This theory described that the Sun is the center of the universe and it was opposed to geocentrism, which placed the Earth at the center. This theory is contrary to the principles of the church and the contents of the Bible at that time. Some scientists oppose the formulation of Nicolaus Copernicus because it contradicts the principles of the church. Although he was in good standing with the Church. At this time, Copernicus was praised by many as the Father of Modern Astronomy. Indeed, his description of the universe was purified and improved by later scientists, such as Galileo, Kepler, and Newton. The controversy of the theory that was sparked by him made us aware of the fragility of scientific concepts that have been accepted for a long time. Through research, observation, and mathematics, Copernicus overturned a scientific and church concept that was rooted but was mistaken that the center of the solar system was the earth, an incorrect concept.Keywords: heliocentrism, the principles of the church, controversyAbstrakHeliosentrisme adalah salah satu teori kontroversial yang ditemukan oleh Nicolaus Copernicus. Teori ini menggambarkan bahwa matahari adalah pusat di alam semesta dan ia menentang geosentrisme, yang menempatkan bumi di tengah. Teori ini bertentangan dengan prinsip-prinsip gereja dan isi Alkitab pada waktu itu. Beberapa ilmuwan menentang perumusan Nicolaus Copernicus karena bertentangan dengan prinsip-prinsip gereja. Meskipun dia dalam posisi yang baik dengan gereja. Pada saat ini, Copernicus dipuji oleh banyak orang sebagai Bapak Astronomi Modern. Memang, uraiannya tentang alam semesta dimurnikan dan ditingkatkan oleh para ilmuwan kemudian, seperti Galileo, Kepler, dan Newton. Kontroversi teori yang dipicu olehnya membuat kita sadar akan kerapuhan konsep-konsep ilmiah yang telah diterima sejak lama. Melalui penelitian, pengamatan, dan matematika, Copernicus menjungkirbalikkan konsep ilmiah dan gereja yang berakar tetapi keliru bahwa pusat tata surya adalah bumi, sebuah konsep yang salah.Kata kunci: heliosentrisme, prinsip-prinsip gereja, kontroversi


Author(s):  
Karel Schrijver

How many planetary systems formed before our’s did, and how many will form after? How old is the average exoplanet in the Galaxy? When did the earliest planets start forming? How different are the ages of terrestrial and giant planets? And, ultimately, what will the fate be of our Solar System, of the Milky Way Galaxy, and of the Universe around us? We cannot know the fate of individual exoplanets with great certainty, but based on population statistics this chapter sketches the past, present, and future of exoworlds and of our Earth in general terms.


Author(s):  
Jan Zalasiewicz

This is the story of a single pebble. It is just a normal pebble, as you might pick up on holiday - on a beach in Wales, say. Its history, though, carries us into abyssal depths of time, and across the farthest reaches of space. This is a narrative of the Earth's long and dramatic history, as gleaned from a single pebble. It begins as the pebble-particles form amid unimaginable violence in distal realms of the Universe, in the Big Bang and in supernova explosions and continues amid the construction of the Solar System. Jan Zalasiewicz shows the almost incredible complexity present in such a small and apparently mundane object. Many events in the Earth's ancient past can be deciphered from a pebble: volcanic eruptions; the lives and deaths of extinct animals and plants; the alien nature of long-vanished oceans; and transformations deep underground, including the creations of fool's gold and of oil. Zalasiewicz demonstrates how geologists reach deep into the Earth's past by forensic analysis of even the tiniest amounts of mineral matter. Many stories are crammed into each and every pebble around us. It may be small, and ordinary, this pebble - but it is also an eloquent part of our Earth's extraordinary, never-ending story.


2021 ◽  
Vol 503 (4) ◽  
pp. 5091-5099
Author(s):  
Dragan Slavkov Hajdukovic ◽  
Sergej Walter

ABSTRACT In a recent paper, quantum vacuum was considered as a source of gravity, and the simplest, phenomenon, the gravitational polarization of the quantum vacuum by an immersed point-like body, was studied. In this paper, we have derived the effective gravitational charge density of the quantum vacuum, caused by two immersed point-like bodies. Among others, the obtained result proves that quantum vacuum can have regions with a negative effective gravitational charge density. Hence, quantum vacuum, the ‘ocean’ in which all matter of the Universe is immersed, acts as a complex fluid with a very variable gravitational charge density that might include both positive and negative densities; a crucial prediction that can be tested within the Solar system. In the general case of ${N \ge {\rm{3}}}$ point-like bodies, immersed in the quantum vacuum, the analytical solutions are not possible, and the use of numerical methods is inevitable. The key point is that an appropriate numerical method, for the calculation of the effective gravitational charge density of the quantum vacuum induced by N immersed bodies, might be crucial in description of galaxies, without the involvement of dark matter or a modification of gravity. The development of such a valuable numerical method, is not possible, without a previous (and in this study achieved) understanding of the impact of a two-body system.


2021 ◽  
pp. 87-93
Author(s):  
Abhijith Ram C ◽  
D Ajith

Space travel has always been a crucial task. Exploration and experimenting on Planets in our solar system will help us understand the universe better and also, we could find the origin of life. Rovers play an important role in finding these answers. The problem we have at present is not only with technology to explore the universe but also the ability of our rockets to carry rovers to other rocks. Since a large amount of fuel is required for Space travel, we end with very little cargo that can be sent to explore. As additive manufacturing started to play a vital part in Mechanical Science, we are going to try to use that tool to build a Generative design that helps in parts consolidation, weight reduction, increase flexibility, design optimisation and cost consolidation. Since weight is an important aspect, we could reduce the present rover weight and add additional scientific tools to the rover to increase its scope of search and applications. This project focuses on features enrichment in Rovers by optimizing rover weight and design using Design for Additive Manufacturing concept.


2021 ◽  
Vol 58 (4) ◽  
pp. 175-195
Author(s):  
Vladimir P. Vizgin ◽  

The article is based on the concepts of epistemic virtues and epistemic vices and explores A. Einstein’s contribution to the creation of fundamental physical theories, namely the special theory of relativity and general theory of relativity, as well as to the development of a unified field theory on the basis of the geometric field program, which never led to success. Among the main epistemic virtues that led Einstein to success in the construction of the special theory of relativity are the following: a unique physical intuition based on the method of thought experiment and the need for an experimental justification of space-time concepts; striving for simplicity and elegance of theory; scientific courage, rebelliousness, signifying the readiness to engage in confrontation with scientific conventional dogmas and authorities. In the creation of general theory of relativity, another intellectual virtue was added to these virtues: the belief in the heuristic power of the mathematical aspect of physics. At the same time, he had to overcome his initial underestimation of the H. Minkowski’s four-dimensional concept of space and time, which has manifested in a distinctive flexibility of thinking typical for Einstein in his early years. The creative role of Einstein’s mistakes on the way to general relativity was emphasized. These mistakes were mostly related to the difficulties of harmonizing the mathematical and physical aspects of theory, less so to epistemic vices. The ambivalence of the concept of epistemic virtues, which can be transformed into epistemic vices, is noted. This transformation happened in the second half of Einstein’s life, when he for more than thirty years unsuccessfully tried to build a unified geometric field theory and to find an alternative to quantum mechanics with their probabilistic and Copenhagen interpretation In this case, we can talk about the following epistemic vices: the revaluation of mathematical aspect and underestimation of experimentally – empirical aspect of the theory; adopting the concepts general relativity is based on (continualism, classical causality, geometric nature of fundamental interactions) as fundamental; unprecedented persistence in defending the GFP (geometrical field program), despite its failures, and a certain loss of the flexibility of thinking. A cosmological history that is associated both with the application of GTR (general theory of relativity) to the structure of the Universe, and with the missed possibility of discovering the theory of the expanding Universe is intermediate in relation to Einstein’s epistemic virtues and vices. This opportunity was realized by A.A. Friedmann, who defeated Einstein in the dispute about if the Universe was stationary or nonstationary. In this dispute some of Einstein’s vices were revealed, which Friedman did not have. The connection between epistemic virtues and the methodological principles of physics and also with the “fallibilist” concept of scientific knowledge development has been noted.


2018 ◽  
Author(s):  
Anil Seth

At the birth of psychology as a science, consciousness was its central problem. But throughout the twentieth century, ideological and methodological concerns pushed the explicit empirical study of consciousness to the sidelines. Since the 1990s, studying consciousness has regained a legitimacy and impetus befitting its status as the central feature of our mental lives. Nowadays consciousness science encompasses a rich interdisciplinary mixture drawing together philosophical, theoretical, computational, experimental, and clinical perspectives. While solving the metaphysically ‘hard’ problem of why consciousness is part of the universe may seem as intractable as ever, scientists have learned a great deal about the neural mechanisms underlying conscious states. Further progress will depend on specifying closer explanatory mappings between (first person subjective) phenomenological descriptions and (third person objective) descriptions of biological and physical processes. Such progress will help reframe our understanding of our place in nature, and may also accelerate clinical approaches to a wide range of psychiatric and neurological disorders.


2017 ◽  
Vol 1 ◽  
pp. 92-110
Author(s):  
Brandon Henrigillis

There are some passages within the Aristotelian corpus that indicate that Aristotle argued for a wider and more cosmic teleology than he is usually understood to have held.  There are two interpretive camps that have been formed as a response to these passages.  The first argues that Aristotle held only the internal teleology that he is commonly associated with, and the second argues that Aristotle must have defended a hierarchical teleology in which some things in the universe are meant to benefit other things.  I argue that both sides are mistaken, and that the key to understanding Aristotelian teleology is through a correct interpretation of Metaphysics Λ 10.


2021 ◽  
Vol 59 (11) ◽  
pp. 1106-1112
Author(s):  
L. A. Gribov ◽  
V. I. Baranov ◽  
I. V. Mikhailov

2021 ◽  
pp. 31-46
Author(s):  
Raymond T. Pierrehumbert

‘Beautiful theories, ugly facts’ evaluates the theories on planetary systems, particularly the Solar System. In 1734, the Swedish polymath Emmanuel Swedenborg proposed that the Sun and all the planets condensed out of the same ball of gas, in what is probably the earliest statement of the nebular hypothesis. The nebular hypothesis entered something close to its modern form in the hands of the French mathematician Pierre-Simon Laplace, who in 1796 made the clear connection to Newtonian gravity. The angular momentum problem and the structure of a protoplanetary disk, the formation of rocky cores, and the gravitational accretion of gas in the disk also come under this topic.


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