scholarly journals Chaotic behaviour in the Solar System

1987 ◽  
Vol 413 (1844) ◽  
pp. 109-129 ◽  
Keyword(s):  
Solar System ◽  
Orbital Evolution ◽  
Chaotic Behaviour ◽  
The Other ◽  
Asteroid Belt ◽  
Essential Ingredient ◽  
The Past

There are several physical situations in the Solar System where chaotic behaviour plays an important role. Saturn’s satellite Hyperion is currently tumbling chaotically. Many of the other irregularly shaped satellites in the Solar System had chaotic rotations in the past. There are also examples of chaotic orbital evolution. Meteorites are most probably transported to Earth from the asteroid belt by way of a chaotic zone. Chaotic behaviour also seems to be an essential ingredient in the explanation of certain non-uniformities in the distribution of asteroids.The long-term motion of Pluto is suspiciously complicated, but objective criteria have not yet indicated that the motion is chaotic.

Precise positions of Triton in 2010–2014 based on Gaia-DR2

2021 ◽  
Author(s):  
Huiyan Zhang ◽  
Yong Yu ◽  
Dan Yan ◽  
Kai Tang ◽  
Rongchuan Qiao
Keyword(s):  
Solar System ◽  
Physical Properties ◽  
Orbital Evolution ◽  
Astronomical Observatory ◽  
Standard Errors ◽  
Origin And Evolution ◽  
Important Target ◽  
Long Time ◽  
Gaia Dr2

Abstract With unique orbital and physical characteristics, Triton is a very important target since it may contain information of the origin and evolution of the solar system. Besides space explorations, ground-based observations over long time also play key role on research of Triton. High-precision positions of Triton obtained from ground telescopes are of great significance for studying its orbital evolution and inverting the physical properties of Neptune. As a long-term observational target, Triton has been observed by the 1.56 m telescope of Shanghai Astronomical Observatory since 1996. In this paper, based on our AAPPDI software and with Gaia DR2 as the reference catalogue, 604 positions of Triton during 2010-2014 are calculated, with standard errors of $19mas-88mas$. A comparison between our results and the ephemeris (DE431+nep096) is also given.

scholarly journals No evidence for interstellar planetesimals trapped in the Solar system

2020 ◽  
Vol 497 (1) ◽  
pp. L46-L49 ◽  
Author(s):  
A Morbidelli ◽  
K Batygin ◽  
R Brasser ◽  
S N Raymond
Keyword(s):  
Solar System ◽  
Oort Cloud ◽  
Giant Planets ◽  
Asteroid Belt ◽  
Interstellar Space ◽  
Fast Decay ◽  
Early Solar System ◽  
The Past ◽  
Solar System Bodies ◽  
Main Asteroid Belt

ABSTRACT In two recent papers published in MNRAS, Namouni and Morais claimed evidence for the interstellar origin of some small Solar system bodies, including: (i) objects in retrograde co-orbital motion with the giant planets and (ii) the highly inclined Centaurs. Here, we discuss the flaws of those papers that invalidate the authors’ conclusions. Numerical simulations backwards in time are not representative of the past evolution of real bodies. Instead, these simulations are only useful as a means to quantify the short dynamical lifetime of the considered bodies and the fast decay of their population. In light of this fast decay, if the observed bodies were the survivors of populations of objects captured from interstellar space in the early Solar system, these populations should have been implausibly large (e.g. about 10 times the current main asteroid belt population for the retrograde co-orbital of Jupiter). More likely, the observed objects are just transient members of a population that is maintained in quasi-steady state by a continuous flux of objects from some parent reservoir in the distant Solar system. We identify in the Halley-type comets and the Oort cloud the most likely sources of retrograde co-orbitals and highly inclined Centaurs.

Unbanked in India: A qualitative analysis of 24 years of financial inclusion policies

2020 ◽  
pp. 002087281988118
Author(s):  
Gaurav R Sinha ◽  
Lissette M Piedra
Keyword(s):  
Policy Design ◽  
Well Being ◽  
Interesting Case ◽  
Financial Inclusion ◽  
The Other ◽  
Design Decisions ◽  
The Past ◽  
Policy Interventions ◽  
Complex Information

Social work has historically engaged in pioneering interventions to improve the financial well-being of people. India is an interesting case as it has the highest number of unbanked people on one side and numerous policy interventions on the other. Using systematic review and Gioia methodology, we analyzed 24 years of financial inclusion policies. Our analysis revealed that the efficacy of policies was impeded by flawed designs, as the policymakers preferred ‘quick fixes’ over long-term solutions. Our study highlights the need for learning from the past and organizing complex information in a way that helps policymakers in taking informed policy design decisions.

scholarly journals Slow and Fast Diffusion in Asteroid-Belt Resonances: A Review

1999 ◽  
Vol 172 ◽  
pp. 25-37
Author(s):  
S. Ferraz-Mello
Keyword(s):  
Solar System ◽  
Chaotic Behaviour ◽  
Asteroid Belt ◽  
Fast Diffusion ◽  
Outer Solar System ◽  
Recent Advances ◽  
Short Period ◽  
Hecuba Gap

AbstractThis paper reviews recent advances in several topics of resonant asteroidal dynamics as the role of resonances in the transportation of asteroids and asteroidal debris to the inner and outer solar system; the explanation of the contrast of a depleted 2/1 resonance (Hecuba gap) and a high-populated 3/2 resonance (Hilda group); the overall stochasticity created in the asteroid belt by the short-period perturbations of Jupiter’s orbit, with emphasis in the formation of significant three-period resonances, the chaotic behaviour of the outer asteroid belt, and the depletion of the Hecuba gap.

Memory of Futures

KronoScope ◽  
2004 ◽  
Vol 4 (2) ◽  
pp. 297-315 ◽  
Author(s):  
Barbara Adam
Keyword(s):  
Genetic Modification ◽  
Nuclear Power ◽  
The Other ◽  
Way Of Life ◽  
Memory Aids ◽  
The Past ◽  
The Future ◽  
The One ◽  
Far Future

AbstractWe think of memories as being focused on the past. However, our ability to move freely in the temporal realm of past, present and future is far more complex and sophisticated than commonsense would suggest. In this paper I am concerned with our capacity to produce and extend ourselves into the far future, for example through nuclear power or the genetic modification of food, on the one hand, and our inability to know the potential, diverse and multiple outcomes of this technologically constituted futurity, on the other. I focus on this discrepancy in order to explore what conceptual tools are available to us to take account of long-term futures produced by the industrial way of life. And I identify some historical approaches to the future on the assumption that the past may well hold vital clues for today's dilemma, hence my proposal to engage in 'memory of futures'. I conclude by considering the potential of 'memory aids for the future' as a means to better encompass in contemporary concerns the long-term futures of our making.

scholarly journals Memory and Alterity in Zar: Religious Contact and Change in the Sudan

2019 ◽  
Vol 8 ◽  
Author(s):  
Susan M Kenyon
Keyword(s):  
Life History ◽  
The Other ◽  
Ethnographic Research ◽  
The Past ◽  
Life History Data ◽  
History Of ◽  
The One ◽  
Ninteenth Century ◽  
Dynamic Interplay

Drawing on long-term ethnographic research in the Blue Nile town of Sennar, supported by archival and historical documentation, this article explores the history of Zar spirit possession in Sudan, and the light this throws on the interplay of religions over the past 150 years. Life history data supports the argument that contemporary Zar is grounded in forms and rituals derived from the ranks of the ninteenth-century Ottoman army, and these remain the basis of ritual events, even as they accommodate ongoing changes in this part of Africa. Many of these changes are linked to the dynamic interplay of Zar with forms of Islam, on the one hand, and Christianity, on the other. In the former colonial periods, political power resided with the British, and Khawaja (European) Christian Zar spirits are remembered as far more important. Today that authority in Zar has shifted to spirits of foreign Muslims and local holy men, on the one hand, and to subaltern Blacks, on the other. These speak to concerns of new generations of adepts even as changes in the larger political and religious landscapes continue to transform the context of Zar.

scholarly journals Avoiding the “Great Filter”: A Projected Timeframe for Human Expansion Off-World

2021 ◽  
Author(s):  
Jonathan Jiang ◽  
Philip Rosen ◽  
Kristen Fahy
Keyword(s):  
World War Ii ◽  
Solar System ◽  
Space Exploration ◽  
Asteroid Belt ◽  
Limiting Factor ◽  
Human Race ◽  
Term Survival ◽  
Long Term Survival ◽  
Life On Earth

Abstract A foundational model has been developed based on trends built from empirical data of space exploration and computing power through the first six plus decades of the Space Age which projects earliest possible launch dates for human-crewed missions from cis-lunar space to selected Solar System and interstellar destinations. The model uses computational power, expressed as transistors per microprocessor, as a key broadly limiting factor for deep space missions’ reach and complexity. The goal of this analysis is to provide a projected timeframe for humanity to become a multi-world species through off-world colonization, and in so doing all but guarantees the long-term survival of the human race from natural and human-caused calamities that could befall life on Earth. Beginning with the development and deployment of the first nuclear weapons near the end of World War II, humanity entered a ‘Window of Peril’ which will not be safely closed until robust off-world colonies become a reality. Our findings suggest the first human-crewed missions to land on Mars, selected Asteroid Belt objects, and selected moons of Jupiter and Saturn can occur before the end of the 21st century. Launches of human-crewed interstellar missions to exoplanet destinations within roughly 40 lightyears of the Solar System are seen as possible during the 23rd century and launch of intragalactic missions by the end of the 24th century. An aggressive and sustained space exploration program, which includes colonization, is thus seen as critical to the long-term survival of the human race.

scholarly journals L’économique de l’habitation : une revue de lalittérature

2009 ◽  
Vol 50 (2) ◽  
pp. 191-231 ◽  
Author(s):  
Alban D’Amours ◽  
Léandre Nadeau
Keyword(s):  
Economic Theory ◽  
Subject Matter ◽  
Econometric Models ◽  
Annotated Bibliography ◽  
The Other ◽  
Residential Construction ◽  
Short Term ◽  
Mortgage Markets ◽  
The Past

Abstract This article has a two-fold purpose: first, to offer as complete an inventory aspossible of the literature written on the economics of housing, classifying thisliterature according to subject matter (in this sense, the article takes on theappearance of an annotated bibliography); and second, to take a hard look at thepresent state of economic theory in this field. The article is divided into the following six sections: 1) existing surveys;2) studies related to long-term cycles in residential construction; 3) theoriesexplaining short-term fluctuations; 4) verbal models; 5) econometric models;6) other studies. Some emphasis has been given to the authors' two principal conclusions. In theiropinion, the "residual" vision and the countercyclical hypothesis have not beenadequately tested in the past. Furthermore, the authors bring to light evidence,both theoretical and factual, which contradicts this theory (see Section 3). Then,in Section 5, the authors attempt to show how econometric models, except in the mostrecent papers, fail to take into account, adequately, the relationships between thehousing and mortgage markets and the builders. In addition, it is contended thatthese models are not truly representational of the whole sector, in that they areoften nothing more than simple demand or supply equations, or, even worse, neitherone nor the other.

scholarly journals Internationalization of soil physics from an American perspective

2012 ◽  
Vol 26 (2) ◽  
pp. 181-185 ◽  
Author(s):  
M. Kirkham
Keyword(s):  
The Other ◽  
Soil Science ◽  
Soil Physics ◽  
Soil Science Society ◽  
Republic Of China ◽  
The Past ◽  
American Perspective ◽  
The Usa ◽  
The Government

Internationalization of soil physics from an American perspectiveUpon the seventy-fifth anniversary of the Soil Science Society of America in 2011, a session was held at its annual meeting to document how the field has changed over the years. I was asked to give the long-term perspective for soil physics. I surveyed soil-physics research published by the society over the past six years (2005-2011) and compared it with a review done in 1961 upon the twenty-fifth anniversary of the society. Of the 299 papers in my survey, 186 came from outside the USA (62% of the total). Twenty-nine countries were represented with the People's Republic of China having the most papers (27 papers). In the 1961 review, only five countries outside the USA were cited. My survey showed that 48 papers (16%) dealt with water, 35 (12%) with mechanical properties, 19 (6%) with aeration, 18 (6%) with solute transport, 14 (5%) with repellency, and 10 (3%) with temperature. Of the non-USA papers in the survey, 27% gave no source of funding and the other 73% usually cited funding by the government of the corresponding author. Of the USA papers, 47% cited no source of funding. The results showed that soil-physics research has become heavily international.

Migration and Educational System in Romania

2018 ◽  
Vol 7 (3) ◽  
pp. 40-49 ◽  
Author(s):  
Marian Zaharia ◽  
Aniela Balacescu
Keyword(s):  
Educational System ◽  
Social Life ◽  
Drop Out ◽  
The Other ◽  
Level Of Education ◽  
Net Migration ◽  
The Past ◽  
School Drop Out ◽  
The One

Over the past two decades, Romania has had an alarming increase in the number of people who have left Romania to work in other countries, with major implications for most areas of economic and social life. The disparities between the eight development regions have led, on the one hand, to the recording of totally different net migration values and, on the other hand, a deepening disparity between development regions. One of the major areas affected by the phenomenon of migration was and is education, with implications on the level of education of the younger generation. This article examines the existence of stable long-term links between school drop-out and net migration in Romania over the period 2000-2016.

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