scholarly journals THE FORGOTTEN GEOGRAPHIC AND PHYSICAL – OCEANOGRAPHIC KNOWLEDGE OF THE PREHISTORIC GREEKS

2017 ◽  
Vol 43 (1) ◽  
pp. 92 ◽  
Author(s):  
I.D Mariolakos
Keyword(s):  
Atlantic Ocean ◽  
Relative Position ◽  
British Isle ◽  
The Sun ◽  
Greek Mythology ◽  
The West ◽  
The Earth ◽  
The Subject ◽  
Greek Myths

Many believe that the Greek Mythology is a figment of the vivid imagination of the ancient Greeks. Consequently, the Greek Myths are all fantastic stories. In my opinion, this view is erroneous, at least on the subject concerning the geographic and physical-oceanographic characteristics of the Atlantic Ocean, as these were described mainly by Homer, Hesiod, the Orphics and Plutarch. In the present paper (i) some of the references made by the above mentioned authors are selectively reported, and (ii) the physical and geological validation is given, based on the present-day scientific views and knowledge. Namely, the prehistoric Greeks knew about the Hyperboreans, the island of Ierne (Ireland), the British isle etc., by the Orphics. From the writings of Plutarch, they knew (i) the relative position of the present-day Iceland (Ogygia) and its distance from Britain, (ii) that to the west of Iceland, three other islands are located, where the sun sets for only an hour a day, (iii) that further to the west there is a “great continent”, which surrounds the Ocean and more. Homer and Hesiod wrote that (i) the Ocean is a “river” that flows continuously, (ii) that this river encircles the Earth and (iii) that its flow is turbulent not only on the surface, but in depth as well. Unfortunately, all this knowledge was gradually forgotten by all. This is the reason why Odyssey is considered just an entertaining poem and Ulysses’ nostos a fantastic story, with no trace of historic reality.

III—Interplanetary Navigation

1955 ◽  
Vol 8 (1) ◽  
pp. 35-40
Author(s):  
J. G. Porter
Keyword(s):  
Dead Reckoning ◽  
Difficult Problem ◽  
Base Line ◽  
The Sun ◽  
Space Navigation ◽  
Simple Matter ◽  
The Earth ◽  
The Subject ◽  
The One ◽  
Interplanetary Navigation

Most people know something about space ships nowadays, and probably think that navigation in space is quite a simple matter; at any rate, it is a subject that is glossed over very briefly in most books on the subject. In my view, space navigation is not a simple matter, and it has certainly not received the attention it deserves. Navigation on the Earth is easy, because of the one important fact that you are on the surface of the Earth. A couple of sights, measuring the angles from two stars down to the horizon, together with the azimuths of the stars and the distance from the centre of the Earth, will give an exact statement of position. But out in space there is no Earth, no horizon—in fact nothing whatever to use as a basis of measurement. Clearly then, two angles are not enough; a third one is needed, to give a sort of tripod of sights—two of the legs being anchored to two planets (or the Sun and a planet) because their positions in space at any time are known, and the distance between them can be used as a base-line. The solution of all the triangles involved is indeed a difficult problem, but there is also the impossibility of making three simultaneous observations. It might be thought that one could do as at sea and take one sight followed later by others, making allowance for the motion of the ship in the intervals. However, this involves the idea of dead reckoning, which, although a useful concept at sea, is quite impossible to apply in space, as the following example shows.

scholarly journals XIII. On the precession of a viscous spheroid, and on the remote history of the Earth

1879 ◽  
Vol 170 ◽  
pp. 447-538 ◽  
Keyword(s):  
Relative Motion ◽  
Mass Motion ◽  
The Sun ◽  
The Earth ◽  
Bodily Tides ◽  
History Of ◽  
The Subject ◽  
Theoretical Dynamics

The following paper contains the investigation of the mass-motion of viscous and imperfectly elastic spheroids, as modified by a relative motion of their parts, produced in them by the attraction of external disturbing bodies; it must be regarded as the continuation of my previous paper, where the theory of the bodily tides of such spheroids was given. The problem is one of theoretical dynamics, but the subject is so large and complex, th at I thought it best, in the first instance, to guide the direction of the speculation by considerations of applicability to the case of the earth, as disturbed by the sun and moon.

VI. The Sun as a Star

1988 ◽  
Vol 20 (1) ◽  
pp. 102-106
Author(s):  
L.E. Cram
Keyword(s):  
Time Scales ◽  
Spatial Extent ◽  
The Sun ◽  
Distinguishing Characteristic ◽  
X Ray ◽  
Spatially Resolved ◽  
Solar Observations ◽  
The Earth ◽  
The Subject

Studies of the global (spatially unresolved) output from the sun are important for two main reasons: (1) the global solar output directed towards the earth plays a central role in solar-terrestrial relations, and (2) global solar observations form a link between (neccessarily) global observations of stars and the more refined spatially resolved observations which are available for the sun. This report covers both aspects (insofar as they concern the sun), using the time-scales of various phenomena as a basic distinguishing characteristic. Note that certain studies of spatially unresolved solar output have not been discussed, since they are actually directed toward the investigation of phenomena of strictly limited spatial extent [e.g. radiospectrograph observations (e.g. Wiehl et al. 1985) and studies of X-ray bursts (e.g. Thomas et al. 1985)]. Collections of relevant papers may be found in De Jager and Svestka (1985) and Labonte et al. (1984), while a review of germane stellar work is available in Baliunas and Vaughan (1985) and solar-terrestrial work in Donnelly and Heath (1985). A comprehensive summary of the subject by Hudson will appear soon in Review of Geophysics and Planetary Physics.

scholarly journals On the precession of the equinoxes

1832 ◽  
Vol 1 ◽  
pp. 253-254
Keyword(s):  
The Sun ◽  
Sir Isaac Newton ◽  
Isaac Newton ◽  
The Third ◽  
The Earth ◽  
Figure Of The Earth ◽  
The Subject

The Professor observes, that Sir Isaac Newton was the first mathematician who endeavoured to estimate the quantity of the precession from the attractive influence of the sun and moon on the spheroidal figure of the earth. His investigations relating to this subject evince the same transcendent abilities that are displayed in other parts of his Principia; but it is admitted, that, from a mistake in his process, his conclusion is erroneous. The investigations of other mathematicians in attempting the solu­tion of the same problem are arranged by the author under three general heads. The first arrive at wrong conclusions, in consequence of mistake in some part of their proceedings; the second obtain just conclusions, but rendered so by balance of opposite errors; the third approach as near the truth as the nature of the subject will admit, but, in the author’s estimation, are liable to the charge of obscurity and perplexity.

scholarly journals IX. On the tidal friction of a planet attended by several satellites, and on the evolution of the solar system

1881 ◽  
Vol 172 ◽  
pp. 491-535 ◽  
Keyword(s):  
Solar System ◽  
Central Body ◽  
The Sun ◽  
Tidal Friction ◽  
The Earth ◽  
History Of ◽  
The Subject ◽  
Complete Investigation

In previous papers on the subject of tidal friction I have confined my attention principally to the case of a planet attended by a single satellite. But in order to make the investigation applicable to the history of the earth and moon it was necessary to take notice of the perturbation of the sun. In consequence of the largeness of the sun’s mass it was not there requisite to make a complete investigation of the theory of a planet attended by a pair of satellites. In the first part of this paper the theory of the tidal friction of a central body attended by any number of satellites is considered.

The Broken Earth: Why the Tetons Are Grand

2000 ◽  
Author(s):  
Robert B. Smith ◽  
Lee J. Siegel
Keyword(s):  
Valley Floor ◽  
The Sun ◽  
Mountain Building ◽  
The West ◽  
The Past ◽  
The North ◽  
The Earth ◽  
Actual Movement ◽  
Jackson Hole ◽  
Teton Range

On a summer morning when the breeze blows cool, it is easy to re the lakes and sagebrush-covered glacial plains of Wyoming’s Jackson Hole sit at nearly 7,000 feet elevation. Yet the altitude of this gorgeous valley is diminished by the view to the west: The precipitous east front of the Teton Range towers above the valley floor, with 13,770-foot Grand Teton and other rugged, snowclad peaks catching the first golden rays of daybreak. This is one of the most spectacular mountain vistas in America. Whether at chill dawn, in glistening light after a torrential afternoon thunderstorm, or during summer evenings when the sun descends behind the lagged Tetons, it is a view that brings solace and peace. Yet the serene splendor of Grand Teton National Park belies a hidden fury. It is not volcanism, which is concealed beneath the gentle pine-covered Yellowstone Plateau to the north. Instead, this defiant topography was born of seismic disaster as the Teton fault repeatedly and violently broke the earth, producing a few thousand magnitude-7 to -7.5 earthquakes during the past 13 million years. During each major jolt, Jackson Hole dropped downward and the Teton Range rose upward, increasing the vertical distance between the valley and the mountains by 3 to 6 feet and sometimes more. Now, after 13 million years of earthquakes, the tallest peaks tower almost 7,000 feet above the valley floor. Actual movement on the fault has been even greater. Jackson Hole dropped downward perhaps 16,000 feet during all those earthquakes. Rock eroded from the Teton Range and other mountains by streams and glaciers filled Jackson Hole with thousands of feet of sediment, disguising how much the valley sank. Combine the uplift of the mountains and the sinking of Jackson Hole, and the best estimate—although still plagued by uncertainty—is that movement on the Teton fault has totaled 23,000 feet during the past 13 million years. That is a tiny fraction of Earth’s 4.6-billion-year history. Consider the effects of repeated episodes of mountain-building during eons before the Teton fault was born: The oldest rocks high in the Teton Range are 2.8-billion-year-old gneisses and schists and 2.4-billion-year-old granites.

scholarly journals Exeter Book Riddle 95: ‘The Sun’, a New Solution

2019 ◽  
Vol 137 (4) ◽  
pp. 612-638
Author(s):  
Dieter Bitterli
Keyword(s):  
Tenth Century ◽  
Exeter Book ◽  
The Sun ◽  
Anglo Saxon ◽  
The Past ◽  
The Earth ◽  
English Verse ◽  
Isidore Of Seville ◽  
The Subject ◽  
The One

Abstract Elusive and fraught with textual difficulties, Riddle 95, the ‘last’ of the Old English verse riddles preserved in the tenth-century Exeter Book, has long baffled modern readers as one of a handful of thorny items in the collection that have so far defied solution. ‘Book’ is the answer that has found most acceptance with critics in the past, yet the speaking subject of Riddle 95 is unlike anything described in those items of the collection that actually deal with writing and the tools of the monastic scriptorium. Rather, the linguistic and thematic parallels between Riddle 95 on the one hand, and the cosmological riddles and poems in the Exeter Book on the other, strongly suggest that the subject of Riddle 95 is the sun, a frequent topic of early medieval enigmatography. The poem obliquely relates how the rising sun installs itself in the sky to shed its welcome light upon the earth before it sets and vanishes from sight, completing its daily orbit along unknown paths. The main clues helping to secure the solution ‘sun’ are based upon what was known in Anglo-Saxon England about the solar course and the planetary motions, especially from the astronomical writings of Isidore of Seville and Bede. Further evidence is provided by several analogues in the Anglo-Latin riddle tradition, including the Enigmata of Aldhelm and his followers.

Perturbations of the orbit of a satellite near to the earth

1958 ◽  
Vol 248 (1252) ◽  
pp. 55-62 ◽  
Keyword(s):  
Satellite Orbit ◽  
The Sun ◽  
The Earth ◽  
First Approximation ◽  
Different Types ◽  
Electromagnetic Effects ◽  
The Subject ◽  
The Cross ◽  
Earth’S Oblateness

The main perturbations of a satellite orbit near the earth are those caused by the earth’s oblateness and the atmosphere. Fortunately these two sources produce perturbations of quite different types, and as a first approximation they can be treated separately, though the cross-couplings would have to be evaluated in a thorough analysis of the subject. There are other perturbations to the orbit, caused by the attractions of the sun, moon and planets, by relativity effects, by the fact that the earth is not symmetrical about its axis and by electromagnetic effects; but these perturbations are expected to be small and will not be discussed here.

Resonance in the Motion of Geocentric Satellites due to Poynting-Robertson Drag

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
Charanpreet Kaur ◽  
Binay Kumar Sharma ◽  
M. Shahbaz Ullah
Keyword(s):  
Angular Velocity ◽  
Orbital Plane ◽  
Ecliptic Plane ◽  
The Sun ◽  
Gravitational Forces ◽  
The Earth ◽  
Time Period ◽  
The Subject ◽  
The Mean ◽  
Two Bodies

The problem of resonance in a geocentric synchronous satellite under the gravitational forces of the Sun and the Earth subject to Poynting-Robertson (P-R) drag is the subject matter of this paper. Based on the assumption that the two bodies the Earth and the Sun lie in ecliptic plane and the satellite in the orbital plane. Five resonance points results from commensurability between the mean motion of the satellite and the average angular velocity of the Earth. Out of all resonance, the 3:2 and 1:2 resonance occurs only due to velocity dependent terms of P-R drag. We have determined the amplitude and time period of the oscillation in two different cases at those resonance points.

Anisotropy in cosmic-ray intensity associated with Forbush decreases

1968 ◽  
Vol 46 (10) ◽  
pp. S854-S858 ◽  
Author(s):  
T. Mathews ◽  
J. B. Mercer ◽  
D. Venkatesan
Keyword(s):  
Daily Variation ◽  
Forbush Decrease ◽  
Cosmic Ray ◽  
Turbulent Plasma ◽  
The Sun ◽  
The West ◽  
Cosmic Ray Intensity ◽  
Rate Of Development ◽  
The Earth ◽  
Scattering Centers

A study of the Forbush decrease of 23 September 1966 shows that the predecrease anisotropy developed from a direction 85° to the west of the sun–earth line. The rate of development of the anisotropy suggests that the "turbulent" plasma producing the Forbush decrease occupied a volume of diameter ≈0.2–0.3 AU. If the plasma clouds away from the earth produced the anisotropy at the earth, then it is reasonable to attribute a part of the highly variable daily variation in cosmic-ray intensity to such distant scattering centers.

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