scholarly journals Commission 20: Positions and Motions of Minor Planets, Comets and Satellites (Positions et Mouvements des Petites Planetes, des Cometes et des Satellites)

1991 ◽  
Vol 21 (1) ◽  
pp. 187-204
Author(s):  
R. M. West

The past triennium was characterized by important advances in several directions within the broad field of this Commission. Among the most exciting events were the Phobos 2 and Voyager 2 missions to Mars/Phobos and Neptune/Triton; their navigation was critically dependent on precise space- and ground-based observations as well as refined theoretical models of the motions in the solar system. Among many other achievements, the secular acceleration of Phobos was accurately measured and the dynamical analysis of the ring-like arcs at Neptune has just begun.

2005 ◽  
Vol 1 (T26A) ◽  
pp. 153-160
Author(s):  
Giovanni B. Valsecchi ◽  
Julio A. Fernández ◽  
J.-E. Arlot ◽  
E.L.G. Bowell ◽  
Y. Chernetenko ◽  
...  

The past triennium has continued to see a huge influx of astrometric positions of small solar system bodies provided by near-Earth object (NEO) surveys. As a result, the size of the orbital databases of all populations of small solar system bodies continues to increase dramatically, and this in turn allows finer and finer analyses of the types of motion in various regions of the orbital elements space.


1979 ◽  
Vol 17 (1) ◽  
pp. 133-144
Author(s):  
B. G. Marsden

The past triennium has been noteworthy for several significant discoveries in the outer part of the solar system. The discovery of the rings of Uranus was inspired by the activities of Commission 20’s new Working Group on Occultations. Although the discovery of a probable Plutonian satellite has not yet been completely confirmed, the implication that Pluto’s mass is only 0.002 earth masses may make it desirable to consider whether Pluto should be relegated to minor-planet status. The orbit of Pluto is in fact not greatly dissimilar to that of the object classified as the new minor planet (2060) Chiron, which was found to have its aphelion near the orbit of Uranus and its perihelion just inside the orbit of Saturn.


1979 ◽  
Vol 17 (1) ◽  
pp. 73-102
Author(s):  
N.B. Richter

Comets, minor planets and meteorites provide us with valuable information about the past history of the solar system. They belong to the most primitive samples of the primordial solar nebula. Over the past years, we can record a considerable increase of interest in these bodies.


1979 ◽  
Vol 81 ◽  
pp. 151-156
Author(s):  
P. J. Shelus ◽  
G. F. Benedict

The development of automatic, computer-controlled, electronic equipment, under the direction of an intelligent user, has significantly affected the output of scientific knowledge from astronomical research. This increased output is as much a result of the easing and/or elimination of heretofore tedious tasks as it is a result of vast increases in data acquisition rates via observing systems which make more efficient use of in-coming electromagnetic radiation. One such automated system (Shelus et al, 1977) has been implemented by the present authors to predict occultations of stars by Solar System objects. In the past these predictions have been a time consuming task which was made even more onerous since only a very few observable phenomena were found. Perhaps of even more importance is that, since candidate objects to be occulted typically were obtained from star catalogs, such a search was incomplete. Note that phenomena involving stars fainter than normal catalog limits are certainly relevant in the cases of Uranus, Neptune, Pluto, minor planets and the natural satellites of the major planets.


1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.


1962 ◽  
Vol 11 (02) ◽  
pp. 137-143
Author(s):  
M. Schwarzschild

It is perhaps one of the most important characteristics of the past decade in astronomy that the evolution of some major classes of astronomical objects has become accessible to detailed research. The theory of the evolution of individual stars has developed into a substantial body of quantitative investigations. The evolution of galaxies, particularly of our own, has clearly become a subject for serious research. Even the history of the solar system, this close-by intriguing puzzle, may soon make the transition from being a subject of speculation to being a subject of detailed study in view of the fast flow of new data obtained with new techniques, including space-craft.


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):  
Lauren Stewart ◽  
Katharina von Kriegstein ◽  
Simone Dalla Bella ◽  
Jason D. Warren ◽  
Timothy D. Griffiths

This article presents an overview of case studies of acquired disorders of musical listening. Like any cognitive faculty, music is multifaceted, and the identification of the neural basis of any complex faculty must proceed, hand in hand, with an elucidation of its cognitive architecture. The past decade has seen an evolution in the theoretical models of musical processing, allowing the development of theoretically motivated instruments for the systematic evaluation of musical disorders. Such developments have allowed reports of musical disorders to evolve from historical anecdotes to systematic, verifiable accounts that can play a critical role in contributing to our understanding of the cognitive neuroscience of music.


Sociologija ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 285-306
Author(s):  
Milan Cakic

The main topic of this article are the motives that led to the adoption of lustration laws in the Czech Republic, Poland, and Serbia, and their social functions. In the opening section, lustration is placed in the wider framework of dealing with the past and two possible approaches to the phenomenon are discussed: to take it as part of the broader process of decommunization, or a measure of transitional justice. In the next section an attempt at defining the concept of lustration is made, with a view to eliminating some ambiguities surrounding it. Subsequently, two partially complementary theoretical models explaining the occurrence, form and severity of dealing with the past and lustration are presented. After that comes the description of the socio-political context at the time of the adoption of lustration laws in the three countries and identification of political and ideological forces that have supported or challenged it. Finally, the article attempts to answer the question whether lustration is a legitimate measure of settling historical justice, overcoming the legacies of socialism, a way to strengthen liberal democracy, or merely a tool in political struggles for power.


2021 ◽  
Author(s):  
◽  
Elspeth Hocking

<p>Public history and academic history have been viewed both as opposites, two practices related only by their concern with sharing the past, as well as conceptualised as similar fields with close connections to each other. Museum history exhibitions are an obvious example of public history in action. However, is the history that exhibitions present all that different from what is produced in the academy, or is this history academia in another form? Initially this dissertation aimed to explore the relationships between academic and public histories as discipline and practice, assuming a relationship rather than divide between the two fields as suggested in some of the literature. However, the eventual results of the research were different than expected, and suggested that in fact public histories manifest very differently to academic histories within a museum context. Using an adapted ethnographic research methodology, this dissertation traces the development of a single history exhibition, "Te Ahi Kā Roa, Te Ahi Kātoro Taranaki War 1860–2010: Our Legacy – Our Challenge", from its concept development to opening day and onwards to public programmes. This exhibition opened at Puke Ariki in New Plymouth in March 2010, and was a provocative display not only of the history of the wars themselves, but of the legacy of warfare in the Taranaki community. Other methods include partially structured interviews which were conducted with ten people involved in creating this exhibition, who outlined their roles in its production and provided their views on its development, and also a brief analysis of the broader social and historical context in which the exhibition was staged. Through tracing the creation of this history, the findings suggested that the history produced at Puke Ariki is a history in its own right, with noticeable differences from academic histories. The strongest correlation between public and academic history in this instance was the shared aspiration to be rigorous in conducting research and, as far as possible, to create an accurate portrayal of the past. Otherwise the history created by Puke Ariki through the exhibition proved to be different in that it was deliberately designed to be very accessible, and it utilised a number of presentation modes, including objects, text, audiovisual and sound. It was interactive, and had a clear aim of enabling the audience to participate in a discussion about the history being presented. Finally, it was a highly politicised history, in that decision making had to be negotiated with source communities in a collaborative fashion, and issues of censorship worked through with the council, a major funding source. The dissertation concludes that producing history in a museum context is a dynamic and flexible process, and one that can be successful despite not necessarily following theoretical models of exhibition development.</p>


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