Spiral and Elliptical Orbits

1957 ◽  
Vol 61 (558) ◽  
pp. 422-423 ◽  
Author(s):  
Rear-Admiral Brian Egerton R.N. (Retd.)
Keyword(s):  
High Altitude ◽  
Circular Orbit ◽  
Artificial Satellite ◽  
Tangential Velocity ◽  
Radius Vector ◽  
The Earth ◽  
Starting Point ◽  
Air Resistance ◽  
Sufficient Distance ◽  
Elliptical Orbits

An Artificial Satellite set to start on a circular orbit round the Earth, will have to be given a known velocity, at right angles to the radius vector, which depends upon its distance from the Earth's centre.It will, from the start, begin to spiral downwards towards the Earth, owing to the resistance of the atmosphere, but if it begins its path at a sufficiently high altitude, the decrease of height after one revolution will be small.Should the initial “ tangential ” velocity be greater than the value calculated for a circular orbit, the satellite will, according to the text books, describe an ellipse instead of a circle; and, if at a sufficient distance for the air resistance to be at first ignored, will return after one revolution to the distance at which it started, this point being the perigee of the ellipse. It will never return to a point outside the starting point.

The motion of a lunar orbiter

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Artificial Satellite ◽  
Equations Of Motion ◽  
Triaxial Ellipsoid ◽  
The Moon ◽  
Secular Motion ◽  
The Earth ◽  
Close Satellite ◽  
The Mean

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.

scholarly journals Practices of sustainability and the enactment of their natures/cultures: Ecosystem services, rights of nature, and geoengineering

2021 ◽  
pp. 053901842199894
Author(s):  
Frank Adloff ◽  
Iris Hilbrich
Keyword(s):  
Ecosystem Services ◽  
Latin American ◽  
Social Systems ◽  
The Earth ◽  
Starting Point ◽  
Knowledge Cultures ◽  
Rights Of Nature ◽  
Value Of Nature ◽  
The One ◽  
And Control

Possible trajectories of sustainability are based on different concepts of nature. The article starts out from three trajectories of sustainability (modernization, transformation and control) and reconstructs one characteristic practice for each path with its specific conceptions of nature. The notion that nature provides human societies with relevant ecosystem services is typical of the path of modernization. Nature is reified and monetarized here, with regard to its utility for human societies. Practices of transformation, in contrast, emphasize the intrinsic ethical value of nature. This becomes particularly apparent in discourses on the rights of nature, whose starting point can be found in Latin American indigenous discourses, among others. Control practices such as geoengineering are based on earth-systemic conceptions of nature, in which no distinction is made between natural and social systems. The aim is to control the earth system as a whole in order for human societies to remain viable. Practices of sustainability thus show different ontological understandings of nature (dualistic or monistic) on the one hand and (implicit) ethics and sacralizations (anthropocentric or biocentric) on the other. The three reconstructed natures/cultures have different ontological and ethical affinities and conflict with each other. They are linked to very different knowledge cultures and life-worlds, which answer very differently to the question of what is of value in a society and in nature and how these values ought to be protected.

LIVE PLANTS AS AN ADDITIONAL BOTANICAL COMPONENTOF THE THEMATIC EXPOSITION IN THE EARTH SCIENCE MUSEUM AT MOSCOW STATE UNIVERSITY

2020 ◽  
Vol 42 (4) ◽  
pp. 478-484
Author(s):  
Kirill Golikov ◽  
Ekaterina LAPTEVA ◽  
A. SOCHIVKO
Keyword(s):  
High Altitude ◽  
Plant Communities ◽  
Earth Science ◽  
Life Forms ◽  
Science Museum ◽  
State University ◽  
Structural Components ◽  
The Earth ◽  
The World ◽  
Moscow State University

The article discusses the use of live plants as the botanical exposition component supplement of the “Natural areas” (hall № 17 “Natural zonality and its components” and № 20 “Desert, subtropical, tropical countries, high-altitude zone”) and “Physico-georaphic regions” (hall № 24 “Continents and parts of the world”) departments in order to visualize information presented in the Earth Science Museum. Demonstration of plants originating from different regions of the world representing different life forms and being structural components of various plant communities allows to visually characterizing thematic aspects of an exposition. That in turn reveal such principles of systematic nature organization as ecobiomorphic and phytocenotic.

The Strait of Magellan—a Gateway to New Worlds

2021 ◽  
Author(s):  
Mauricio Onetto Pavez
Keyword(s):  
Global Scale ◽  
Modern World ◽  
American Continent ◽  
The Earth ◽  
Starting Point ◽  
Strait Of Magellan ◽  
The World ◽  
The Strait Of Magellan ◽  
History Of ◽  
First Time

The year 2020 marks the five hundredth anniversary of the “discovery” of the Strait of Magellan. The unveiling of this passage between 1519 and 1522 allowed the planet to be circumnavigated for the first time in the history of humanity. All maritime routes could now be connected, and the idea of the Earth, in its geographical, cosmographic, and philosophical dimensions, gained its definitive meaning. This discovery can be considered one of the founding events of the modern world and of the process of globalization that still continues today. This new connectivity awoke an immediate interest in Europe that led to the emergence of a political consciousness of possession, domination, and territorial occupation generalized on a global scale, and the American continent was the starting point for this. This consciousness also inspired a desire for knowledge about this new form of inhabiting the world. Various fields of knowledge were redefined thanks to the new spaces and measurements produced by the discovery of the southern part of the Americas, which was recorded in books on cosmography, natural history, cartography, and manuscripts, circulating mainly between the Americas and Europe. All these processes transformed the Strait of Magellan into a geopolitical space coveted by Europeans during the 16th century. As an interoceanic connector, it was used to imagine commercial routes to the Orient and political projects that could sustain these dynamics. It was also conceived as a space to speculate on the potential wealth in the extreme south of the continent. In addition, on the Spanish side, some agents of the Crown considered it a strategic place for imperial projections and the defense of the Americas.

Effect of a high-altitude nuclear detonation on the Earth-ionosphere cavity

1963 ◽  
Vol 68 (13) ◽  
pp. 4115-4118 ◽  
Author(s):  
Martin Balser ◽  
Charles A. Wagner
Keyword(s):  
High Altitude ◽  
The Earth

3D UAV trajectory planning using evolutionary algorithms: A comparison study

2015 ◽  
Vol 119 (1220) ◽  
pp. 1271-1285 ◽  
Author(s):  
M. Bagherian ◽  
A. Alos
Keyword(s):  
Trajectory Planning ◽  
Three Dimensional ◽  
Particle Swarm ◽  
Geographic Information ◽  
Flight Path ◽  
Planning Problem ◽  
The Earth ◽  
Swarm Algorithms ◽  
Starting Point ◽  
Wide Range

Abstract This paper focuses on the three dimensional flight path planning for an unmanned aerial vehicle (UAV) on a low altitude terrain following\terrain avoidance mission. The UAV trajectory planning problem is to compute an optimal or near-optimal trajectory for a UAV to do its mission objectives in a surviving penetration through the hostile enemy environment, considering the shape of the earth and the kinematics constraints of the UAV. Using the three dimensional terrain information, three dimensional flight path from a starting point to an end point, minimising a cost function and regarding the kinematics constraints of the UAV is calculated. The geographic information of the earth shape and enemy locations is generated using digital terrain model (DTM) and geographic information system (GIS), and is displayed in a 3D environment. Using 3D-maps containing the geographic data accompanied by DTM, and GIS, the problem is modelled by deriving the motion equations of the UAV. Two heuristic algorithms are proposed for this problem: genetic and particle swarm algorithms. Genetic and particle swarm algorithms are general purposes algorithms, because they can solve a wide range of problems, so they have to be adjusted to solve the trajectory planning problem. To test and compare the paths obtained from these algorithms, a software program is built using GIS tools and the programming languages C# and MATLAB.

The Aerospace Plane: Collisions and Damage to a Third Party on the Surface of the Earth: Which Liability Regime will Rule?

1991 ◽  
Vol 4 (2) ◽  
pp. 249-280
Author(s):  
Lousewies S.A.L.B van der Laan
Keyword(s):  
Outer Space ◽  
Third Party ◽  
Chicago Convention ◽  
Legal Regime ◽  
The Earth ◽  
Legal Questions ◽  
Starting Point ◽  
Outer Space Treaty ◽  
Definition Of ◽  
Aerospace Plane

The article addresses the establishment of a legal regime concerning liability questions of the aerospace plane. The existing air and space law, as laid down for example in the Chicago Convention and the Outer Space Treaty -especially the definition of the words ‘aircraft’ and ‘space object’-is used as a starting point. The applicability of the existing regimes to the aerospace plane is then evaluated. Two concrete cases, namely liability resulting from damage to third parties on the suiface of the earth and liability after collisions, are presented in depth to illustrate the legal questions that this new hybrid craft will raise. Finally some modest suggestions are made as to the resolution of the conflicts.

DiG-DAG: Didactic Game for Divulgation of Understandable Geophysics

2020 ◽  
Author(s):  
Giuliana D'Addezio ◽  
Valerio Lombardo ◽  
Stefania Conte ◽  
Anna De Santis
Keyword(s):  
High School Students ◽  
Young People ◽  
Computer Game ◽  
Great Level ◽  
School Students ◽  
The Earth ◽  
Starting Point ◽  
Educational Computer ◽  
Gaming Environment ◽  
Educational Computer Game

<p>Geophysics is the application of the laws and techniques of physics to disclose knowledge about the Earth’s dynamic processes and subsurface structure. It explores phenomena such as earthquakes, volcanoes, tsunamis to improve our understanding of the Earth’s physical processes. Effective mitigation of risks from catastrophic geophysics hazards requires knowledge and understanding of natural processes. Scientific divulgation deals with the communication of knowledge previously produced in scientific contexts to a non-expert massive audience.  One of the difficulties science divulgators need to overcome is to explain specific concepts, even complex, from a given discipline in a language simple and understandable, maintaining scientific correctness, and enhance skills, knowledge and competences of their interlocutors.</p><p>Considering that, nowadays, digital technologies play a large role in young people’s lives and games are directly connected to the life of adolescents, we realized an educational videogame to teach geophysics and Earth sciences to low and high-school students; an educational computer game, serious game, where electronic medium with all the characteristic of a gaming environment convey formative outcomes. The starting point is that technologies are systems of open possibilities that can be effectively integrated with innovative methods of education necessary to promote more effective, efficient, attractive and durable learning. In fact, the ardour and enthusiasm that digital games evoke in teenagers has brought many researchers, school leaders and teachers to the question “how video games” can be used to engage young people and support their learning.</p><p>A first stage of the project of Virtual Reality, "Journey inside the volcano", were presented at several scientific divulgative events, such as the ESA Living Planet Symposium, The National Geographic Festival delle Scienze, the September 29th INGV Open Day, involving more that a thousand users and receiving appreciation from the public. We present the serious game and the relate appreciation analysis based on guestbook comments compiled at the end of the experience. The comments reveal a great level of appreciation, involvements and emotions, and margins of improvement. The results foster us to improve the project developing other geophysical topics.</p>

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