2. On the History of the Sun's Distance Determinations; and on Scriptural and Scientific Probabilities

1869 ◽  
Vol 6 ◽  
pp. 307-308
Author(s):  
William Petrie

This paper was accompanied by two diagrams, one of them representing more particularly the features attending on space, and the probable errors of several modern determinations therein; and the other representing the chronological order of the events, or progress made by man from the earliest times, down to the present, in ascertaining that most important of all questions in astronomy and general physics, viz., the true mean distance of the earth from the sun.

Nuncius ◽  
2020 ◽  
Vol 35 (2) ◽  
pp. 235-250
Author(s):  
Rory McEvoy

Abstract In his 1734 discourse on the planetarium, John Theophilus Desaguliers was careful to point out that the invention of the orrery had been incorrectly attributed to John Rowley and that it was George Graham who had made the first truthful working model of the Earth and Moon’s motion around the Sun. Two such models by Graham survive in Museum collections: one at the Adler Planetarium in Chicago and the other at the History of Science Museum in Oxford, UK. This paper assesses the differences between the two instruments and the physical evidence contained within to test out the unfounded assertion made by Henry C. King that the Adler instrument is the prototype and the Oxford orrery a developed commercial product.


Apeiron ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dirk L. Couprie

Abstract In this paper, three problems that have hardly been noticed or even gone unnoticed in the available literature in the cosmology of Philolaus are addressed. They have to do with the interrelationships of the orbits of the Earth, the Sun, and the Moon around the Central Fire and all three of them constitute potentially insurmountable obstacles within the context of the Philolaic system. The first difficulty is Werner Ekschmitt’s claim that the Philolaic system cannot account for the length of the day (νυχϑήμερον). It is shown that this problem can be solved with the help of the distinction between the synodic day and the sidereal day. The other two problems discussed in this paper are concerned with two hitherto unnoticed deficiencies in the explanation of lunar eclipses in the Philolaic system. The Philolaic system cannot account for long-lasting lunar eclipses and according to the internal logic of the system, during lunar eclipses the Moon enters the shadow of the Earth from the wrong side. It is almost unbelievable that nobody, from the Pythagoreans themselves up to recent authors, has noticed these two serious deficiencies, and especially the latter, in the cosmology of Philolaus the Pythagorean.


1879 ◽  
Vol 170 ◽  
pp. 447-538 ◽  

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.


1828 ◽  
Vol 118 ◽  
pp. 379-396 ◽  
Keyword(s):  
The Sun ◽  

The facts which I communicated in my former paper on this subject appeared so inexplicable on any known principle, that I am induced to present my subsequent observations to the Society, although I have not succeeded in ascertaining the causes of the singular effects which I have observed. From the experiments described in that paper, it appeared that a magnetized needle, when vibrated exposed to the sun’s rays, will come to rest sooner than when screened from their influence: that a similar effect is produced on a needle of glass or of copper; but that the effect upon the magnetized needle greatly exceeds that upon either of the others. To the experiments from which this was inferred, it might be objected, that the magnetized needle and the other metallic needle were not of the same weight, and that the effect upon an unmagnetized steel needle had not been compared with that upon a similar needle magnetized. I therefore, on the first opportunity, made these experiments in the most unexceptionable manner, and the results most decidedly confirmed those I had previously obtained. I endeavoured likewise to ascertain the effects that would be produced by the separate rays; but, possibly owing to the inefficiency of my apparatus, I obtained no very decided results: the violet rays appeared to produce the same effect as partially screening the needle; and the red rays, the greatest effect in diminishing the arc of vibration. The observations themselves will however best point out the nature of these effects. My first object was to compare the effects on an unmagnetized steel needle with those on a magnetized needle, under circumstances as nearly as possible the same. For this purpose I made another needle of the same form and weight, and from the same piece of clock-spring, as the magnetized needle which I had already employed. Each needle had pasteboard glued to the under side, to render it of precisely the same weight as two other needles of copper and of glass, which I had cut of the same form for the purpose of comparing the effects upon needles of different kinds. The length of each needle is 6 inches, and the greatest breadth 1.5 inch, the boundaries being circular arcs. The needles were vibrated by means of an apparatus, described in my former paper, from which metal was scrupulously excluded; the suspending wire being the only metal within several feet of the needle. This wire was of brass, and of such diameter, that the unmagnetized needles vibrated by the force of its torsion in very nearly the same time as the magnetized needle by the directive force of the earth. The observations are contained in the following table, where the terminal arc is, in all cases, the extent to which the needle vibrated beyond zero after completing the 100th vibration; and the terminal excess is the excess of the terminal arc when the needle vibrated in the shade above that when it vibrated exposed to the sun.


In the Philosophical Transactions for the year 1767, a suggestion is thrown out by Mr. Michell, that a comparison between the light received from the sun and any of the fixed stars, might furnish data for estimating their relative distances; but no such direct comparison had been attempted. Dr. Wollaston was led to infer from some observations that he made in the year 1799, that the direct light of the sun is about one million times more intense than that of the full moon, and therefore very many million times greater than that of all the fixed stars taken collectively. In order to compare the light of the sun with that of a star, he took, as an intermediate object of comparison, the light of a candle reflected from a small bulb, about a quarter of an inch in diameter, filled with quicksilver, and seen, by one eye, through a lens of two inches focus, at the same time that the star or the sun’s image, placed at a proper distance, was viewed by the other eye through a telescope. The mean of various trials seemed to show that the light of Sirius is equal to that of the sun seen in a glass bulb one tenth of an inch in diameter, at the distance of 210 feet, or that they are in the proportion of one to ten thousand millions; but as nearly one half of the light is lost by reflection, the real proportion between the light from Sirius and the sun is not greater than that of one to twenty thousand millions. If the annual parallax of Sirius be half a second, corresponding to a distance of 525,481 times that of the sun from the earth, its diameter would be 3⋅7 times that of the sun, and its light 13⋅8 times as great. The distance at which the sun would require to be viewed, so that its brightness might be only equal to that of Sirius, would be 141,421 times its present distance; and if still in the ecliptic, its annual parallax in longitude would be nearly 3″; but if situated at the same angular distance from the ecliptic as Sirius is, it would have an annual parallax, in latitude, of 1″⋅8.


1988 ◽  
Vol 7 (1) ◽  
pp. 38-47
Author(s):  
C. P. Snyman

In view of the principle of actualism the early history of the earth must be explained on the basis of present-day natural phenomena and the basic Laws of Nature. The study of the solar system leads to the conclusion that the planets were formed as by-products when the sun developed from a rotating cloud of cosmic gas and dust. The protoplanets or planetesimals could have accreted as a result of mutual collisions, during which they could have become partly molten so that they could differentiate into a crust, a mantle and a core on the basis of differences in density.


1956 ◽  
Vol 6 (1-2) ◽  
pp. 40-44 ◽  
Author(s):  
W. K. C. Guthrie
Keyword(s):  
The Sun ◽  

The following remarks are frankly speculative, and their subject one on which certainty is unlikely to be attained. It seems worth offering them because, though the conclusions are only tentative, they were reached by way of some observations which have a certain interest of their own.Anaximenes, we are told, said that the sun is flat like a leaf, and that it and the other heavenly bodies ‘ride upon’ the air owing to their flat shape, as does the earth also.


The Geologist ◽  
1861 ◽  
Vol 4 (8) ◽  
pp. 332-347
Author(s):  
W. Pengelly

The rooks composing the earth's crust contain a history and represent time—a history of changes numerous, varied, and important: changes in the distribution of land and water; in the thermal conditions of the world; and in the character of the organic tribes which have successively peopled it. The time required for these mutations must have been vast beyond human comprehension, requiring, for its expression, units of a higher order than years or centuries. In the existing state of our knowledge it is impossible to convert geological into astronomical time: it is at present, and perhaps always will be, beyond our power to determine how many rotations on its axis, or how many revolutions round the sun the earth made between any two recognised and well-marked events in its geological history. Nevertheless it is possible, and eminently convenient, to break up geological time into great periods: it must not be supposed, however, that such periods are necessarily equal in chronological, organic, or lithological value; or separated from one another by broadly marked lines of demarcation; or that either their commencements or terminations in different and widely separated districts were strictly synchronous.One of the terms in the chronological series of the geologist is known as the Devonian, that which preceeded it the Silurian, and the succeeding one the Carboniferous period; and these, with some others of less importance, belong to the Palæozoic or ancient-life epoch, or group of periods.


1977 ◽  
Vol 6 (4) ◽  
pp. 15-20
Author(s):  
Eduardo Galeano ◽  
William Rowe

During long sleepless nights and days of depression, a fly buzzes and buzzes around the head:' Writing, is it worth it?' In the midst of the farewells and the crimes, will words survive? Does this profession, which one has chosen or which has been chosen for one, make any sense? I am South American. In Montevideo, where I was born, I edited some newspapers and journals; one after the other they were closed down, by the government or by the creditors. I wrote several books: they are all banned. At the beginning of ‘73, my exile began. In Buenos Aires, we founded Crisis. It was a cultural journal with the biggest circulation in the history of the Spanish language. In August of last year its last number appeared. It could not continue. When words can be no worthier than silence, it is better to say nothing. And to hope. Where are the writers and journalists who produced the journal? Almost all have left Argentina, Some are dead. Others, imprisoned or disappeared. The novelist Haroldo Conti, or what remained of him, was seen for the last time in the middle of May 1976. Broken by torture. Nothing more has been heard of him. Officially, he was not detained. The government washes its hands. The poet Miguel Angel Bustos was taken from his home and has disappeared. The poet Paco Urondo was killed in Mendoza. The writers Paoletti and Di Benedetto are in prison: As is Luis Sabini, the journal's head of production: he is accused of possessing arms because he had a bullet to make himself a key ring. Our editor, Carlos Villar Arauja, was the first to go. In July 1975 he had to leave the country. He had published a courageous work, with documentary evidence, on oil in Argentina. That edition of Crisis was put on sale in the kiosks and, six evenings later, Carlos did not come home to sleep. They interrogated him with his eyes covered. The police denied holding him. Two days later he was flung, by a miracle still alive, into the woods of Ezeiza. The police said they had arrested him by mistake. They circulated lists of those condemned to death. The poet, Juan Gelman, editor in chief, had to take a plane. Some time later, they came looking for him in his home in Buenos Aires. As he was not there, they took his children away. The daughter turned up alive. Of the son and daughter-in-law, seven months pregnant, nothing is known. Unofficial government information indicated that they had been in prison and had been set free. The earth has swallowed them up. In such stormy times, the profession of writing is dangerous. In such circumstances, one recovers pride and joy in words, or loses respect for them for ever.


2015 ◽  
Vol 10 (S318) ◽  
pp. 142-143
Author(s):  
Julio A. Fernández ◽  
Andrea Sosa

AbstractWe analyze the dynamics and activity observed in bodies approaching the Earth (perihelion distancesq< 1.3 au) in short-period orbits (P< 20 yr), which essentially are near-Earth Jupiter Family Comets (NEJFCs) and near-Earth asteroids (NEAs). In the general definition, comets are “active”, i.e. they show some coma, while asteroids are “inactive”, i.e. they only show a bare nucleus. Besides their activity, NEJFCs are distinguished from NEAs by their dynamical evolution: NEJFCs move on unstable orbits subject to frequent close encounters with Jupiter, whereas NEA orbits are much more stable and tend to avoid close encounters with Jupiter. However, some JFCs are found to move on stable, asteroidal-type orbits, so the question arises if these objects are asteroids that have become active, perhaps upon approach to the Sun. In this sense they may be regarded as the counterparts of the main-belt comets (Hsieh & Jewitt 2006). On the other hand, some seemingly inert NEAs move on unstable, comet-type orbits, so the question about what is a comet and what is an asteroid has become increasingly complex.


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