I. On the grounds of the method which laplace has given in the second chapter of the third book of his mémcanique céleste for computing the attractions of spheroids of every description

1812 ◽  
Vol 102 ◽  
pp. 1-45 ◽  
Keyword(s):  
Joint Effect ◽  
Uniform Density ◽  
Sir Isaac Newton ◽  
Isaac Newton ◽  
The Earth ◽  
Celestial Bodies ◽  
Primitive Condition ◽  
The Subject ◽  
Rotatory Motion ◽  
Complicated Nature

In every physical inquiry the fundamental conditions should be such as are supplied by observation. Were it possible to observe this rule in every case, theory would always comprehend in its determinations a true account of the phenomena of nature. Applying the maxim we have just mentioned to the question concerning the figure of the planets, the mathematician would have to investigate the figure which a fluid, covering a solid body of any given shape, and composed of parts that vary in their densities according to a given law, would assume by the joint effect of the attraction on every particle and a centrifugal force produced by a rotatory motion about an axis. The circumstances here enumerated are all that observation fully warrants us to adopt as the foundation of this inquiry: for, with regard to the earth we know little more than that it consists of a solid nucleus, or central part, covered with the sea; and with regard to the other planets, all our knowledge is derived from analogy which leads us to think that they are bodies resembling the earth. There is one consideration, however, by which the general research may be modified without hurting the strictest rules of philosophizing; and that is, the near approach to the spherical figure which is observed in all the celestial bodies : and it is fortunate that this circumstance contributes much to lessen the great difficulties that occur in the investigation. But, even with the advantage derived from this limitation, the inquiry is extremely difficult, and leads to calculations of the most abstruse and complicated nature; and, when viewed in the general manner we have mentioned, it far surpassed the power of the mathematical and mechanical sciences as they were known in the days of Sir Isaac Newton, who first considered the physical causes of the figure of the planets. That great man was therefore forced to take a more confined view of the subject and to admit such suppositions as seemed best adapted to simplify the investigation. He supposed in effect that the earth and planets at their creation were entirely fluid, and that they now preserve the same figures which they assumed in their primitive condition; a hypothesis by which the inquiry was reduced to determine the figure necessary for the equilibrium of a fluid mass. The mathematicians, who have followed in the same tract of inquiry, have seldom ventured to go beyond the limited supposition proposed by Newton. They have succeeded in shewing that a mass revolving about an axis, and composed of one fluid of a uniform density, or of different fluids of different densities, will be in equilibrium, and will for ever preserve its figure when it has the form of an elliptical spheroid of revolution oblate at the poles. It has likewise been proved that the same form is the only one capable of fulfilling the required conditions ; which completes the solution of the problem in so far as it regards a mass entirely fluid.

On the attractions of homogeneous ellipsoids

1832 ◽  
Vol 1 ◽  
pp. 341-341
Keyword(s):  
Centrifugal Force ◽  
Second Order ◽  
Mutual Attraction ◽  
Sir Isaac Newton ◽  
Isaac Newton ◽  
The Subject ◽  
Rotatory Motion

The theory of the figures of the planets involves two questions perfectly distinct from each other; first, the figure which a mass of matter would assume by the mutual attraction of its particles, combined with a centrifugal force, arising from rotatory motion; and secondly, the force with which a body so formed will attract a particle occupying any proposed situation. The latter is the subject of the present inquiry; and it is also limited to the consideration of homogeneous bodies bounded by finite surfaces of the second order. This subject was first partially treated of by Sir Isaac Newton, who, in determining the attraction of spherical bodies, has also treated of other solids, formed by the rotation of curves round an axis, and of the attractions they exert upon bodies placed in the line of their axes. MacLaurin was the first who determined the attractions that such spheroids of revolutions exert on particles placed anywhere, either in or within their surfaces.

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 On the grounds of the method which Laplace has given in the chapter of the third book of his Mécanique Céleste for computing the attractions of spheroids of every description

1832 ◽  
Vol 1 ◽  
pp. 413-415
Keyword(s):  
Gradual Increase ◽  
Sir Isaac Newton ◽  
Isaac Newton ◽  
The Third ◽  
Fluid State ◽  
The Earth ◽  
Figure Of The Earth ◽  
Primitive Condition ◽  
Uniform Fluid

Sir Isaac Newton, who first considered the figure of the earth and planets, confined his view to the supposition of their having been originally in a fluid state; and he conceived them to retain the same figure which they assumed in their primitive condition; and those mathematicians who succeeded him in the same path of inquiry have seldom ventured beyond this limited hypothesis, and have shown, that when a body composed of one uniform fluid revolves about its axis, or even if it consists of several fluids of different densities, its parts will be in equilibrium, and it will preserve its figure when it has the form of an elliptic spheroid of revolution oblate at the poles. But though the supposition of original fluidity of the mass simplifies the investigation, it does not seem to be warranted by what we see of the surface; for in that case, Mr. Ivory observes, the arrangement of all the heterogeneous matters would have been according to their densities; those least dense occupying the surface with gradual increase of density to the centre; whereas, on the contrary, nothing can be more irregular than the density of such solid parts of the earth as come under our observation, and the elevation of continents above the level of the sea, as well as the depths of the different channels which contain the waters of the ocean.

II. On the precession of the equinoxes

1807 ◽  
Vol 97 ◽  
pp. 57-82
Keyword(s):  
Natural Philosophy ◽  
The Other ◽  
The Sun ◽  
Sir Isaac Newton ◽  
Isaac Newton ◽  
The Third ◽  
The Earth ◽  
Figure Of The Earth ◽  
The Subject ◽  
Theory Of Gravity

Perhaps the solution of no other problem, in natural philo­sophy, has so often baffled the attempts of mathematicians as that of determining the precession of the equinoxes, by the theory of gravity. The phenomenon itself was observed about one hundred and fifty years before the Christian æra, but Sir Isaac Newton was the first who endeavoured to estimate its magnitude by the true principles of motion, combined with the attractive influence of the sun and moon on the spheroidal figure of the earth. It has always been allowed, by those competent to judge, that his investigations relating to the subject evince the same transcendent abilities as are displayed in the other parts of his immortal work, the mathematical Principles of natural Philosophy, but, for more than half a century past, it has been justly asserted that he made a mistake in his process, which rendered his conclusions erro­neous. Since the detection of this error, some of the most eminent mathematicians in Europe have attempted solutions of the problem. Their success has been various; but their investi­gations may be arranged under three general heads. Under the first of these may be placed such as lead to a wrong conclusion, in consequence of a mistake committed in some part of the proceedings. The second head may be allotted to those in which the conclusions may be admitted as just, but rendered so by the counteraction of opposite errors. Such may be ranked under the third head as are conducted without error fatal to the conclusion, and in which the result is as near the truth as the subject seems to admit.

scholarly journals XXIV. A discourse concerning the menstrual parallax, arising from the mutual gravitation of the Earth and Moon; it's influence on the observations of the Sun and Planets; with a method of observing it: By J. Smeaton, F. R. S

1768 ◽  
Vol 58 ◽  
pp. 156-169 ◽  
Keyword(s):  
Center Of Gravity ◽  
The Sun ◽  
Sir Isaac Newton ◽  
Isaac Newton ◽  
The Earth ◽  
Common Center

It is demonstrated by Sir Isaac Newton in the Principia , that it is not the Earth's center, but the common center of gravity of the Earth and Moon, that describes the ecliptic; and that the Earth and Moon revolve in similar ellipses, about their common center of gravity.

scholarly journals At the Anniversary Meeting, November 30, 1844

1851 ◽  
Vol 5 ◽  
pp. 519-538
Keyword(s):  
Royal Society ◽  
Sir Isaac Newton ◽  
Isaac Newton ◽  
Legal Proceedings ◽  
The Public ◽  
Foreign Countries ◽  
The Subject ◽  
The Government ◽  
The Antarctic

Gentlemen, The time has again come round for my addressing you, and for ex­pressing my own gratitude, as well as yours, to your Council for their constant and zealous attention to the interests of the Royal Society. We have been compelled during several late years to have recourse to legal proceedings on the subject of the great tithes of Mablethorp, a portion of the Society’s property, and I rejoice to say with success. In my last address, I was required to give our thanks to Mr. Watt and to Mr. Dollond for the valuable busts which they had kindly presented to us. That of Mr. Dollond is placed at the commence­ment of the staircase leading to our apartments, and serves to indi­cate that his valuable improvements in the construction of our tele­scopes have been so many steps to the acquisition of higher and higher knowledge of the great universe of which this globe forms so insignificant a part. By the liberality of Mr. Watt we shall soon be furnished with handsome pedestals for the busts of his father and of Sir Isaac Newton, the two great lights of British mechanical genius and British philosophical science. Mr. Gilbert has kindly undertaken to furnish a similar pedestal for the bust of his father, and we have thought it right to provide one for that of Sir Joseph Banks. These will shortly form a conspicuous ornament of our place of meeting. The magnetical observatories are still carrying on their observa­tions, both in Her Majesty’s dominions and in foreign countries, and another naval officer, Lieut. Moore, has proceeded to the Antarctic Seas to complete a portion of the survey of Captain Sir James Ross, which was interrupted by stress of weather. That gallant and enter­ prising officer will, I hope, ere long give to us and to the public his own narrative of his important discoveries. Detailed accounts of the botany and zoology of the regions visited by him are preparing under the patronage of the Government, while Colonel Sabine is proceeding with the raagnetical observations, which were the more immediate objects of this, one of the most important voyages of discovery ever undertaken.

Brighter than how many suns? Sir Isaac Newton’s burning mirror

1989 ◽  
Vol 43 (1) ◽  
pp. 31-51 ◽  
Keyword(s):  
Royal Society ◽  
Scientific Literature ◽  
Radiant Heat ◽  
The Other ◽  
Sir Isaac Newton ◽  
Isaac Newton ◽  
Other Hand ◽  
The Press ◽  
The Subject ◽  
Hearsay Evidence

There are a number of references in the scientific literature to a burning mirror designed by Sir Isaac Newton (1). Together, they record that it was made from seven separate concave glasses, each about a foot in diameter, that Newton demonstrated its effects at several meetings of the Royal Society and that he presented it to the Society. Nonetheless, neither the earliest published list of instruments possessed by the Royal Society nor the most recent one mentions the burning mirror; the latest compiler does not even include it amongst those items, once owned, now lost. No reference to the instrument apparently survives in the Society’s main records. It is not listed by the author of the recent compendium on Newton’s life and work (2). There is, however, some contemporary information still extant (Appendix 1). Notes of the principles of its design and some of its effects are to be found in the Society’s Journal Book for 1704; some of the dimensions and the arrangement of the mirrors are given in a Lexicon published by John Harris which he donated to the Royal Society at the same meeting, 12 July 1704, at which Newton gave the Society the speculum. The last reference in the Journal Book is dated 15 November that year, when Mr Halley, the then secretary to the Society, was desired to draw up an account of the speculum and its effects (3). No such account appears to have been presented to the Royal Society. There is no reference in Newton’s published papers and letters of his chasing Halley to complete the task, nor is there any mention of it in the general references to Halley. The latter was, of course, quite accustomed to performing odd jobs for Newton; that same year he was to help the Opticks through the press. The only other contemporary reference to the burning mirror, though only hearsay evidence since Flamsteed was not present at the meeting, is in a letter the latter wrote to James Pound; this confirms that there were seven mirrors and that the aperture of each was near a foot in diameter (4). Because John Harris gave his Dictionary to the Royal Society in Newton’s presence, it is reasonable to assume that his description is accurate. As Newton would hardly have left an inaccurate one unchallenged, then, belatedly, the account desired of Mr Halley can be presented. In some respects, the delay is advantageous, since the subject of radiant heat and its effects, although already by Newton’s period an ancient one, is today rather better understood. On the other hand, some data has to be inferred, that could have been measured, and some assumptions made about Newton’s procedures and understanding that could have been checked (5).

scholarly journals XX. On the attractions of homogeneous ellipsoids

1809 ◽  
Vol 99 ◽  
pp. 345-372 ◽  
Keyword(s):  
Centrifugal Force ◽  
Planetary System ◽  
Joint Effect ◽  
Second Order ◽  
Mutual Attraction ◽  
The Subject ◽  
Rotatory Motion

1. The theory of the figures of the planets involves in it two distinct researches. In the first of these, it is required to determine the force with which a body, of a given figure and density, would attract a particle of matter, occupying any proposed situation: in the second, the subject of investigation is the figure itself, which a mass of matter, wholly or partly fluid, would assume, by the joint effect of the mutual attraction of its particles, and a centrifugal force arising from a rotatory motion about an axis. To render the second of these inquiries more exactly conformable to what actually takes place in nature, the influence of the attractions of the several bodies, that compose the planetary system, ought to be super-added to the forces already mentioned. It is the first of these two researches, of which we propose to treat at present; and we shall even confine our attention to homogeneous bodies, bounded by finite surfaces of the second order.

Historically Speaking,— Sir Isaac Newton: 1642-1727

1958 ◽  
Vol 51 (2) ◽  
pp. 124-127
Keyword(s):  
Sir Isaac Newton ◽  
Isaac Newton ◽  
The Subject

Isaac Newton has received so many honors and has been the subject of so many biographies both during his lifetime and in the two hundred and thirty years since his death that such a note as we can write here seems hardly necessary.

scholarly journals A View to Anorthosites

2021 ◽  
Author(s):  
Homayoon Mohammadiha
Keyword(s):  
Plate Tectonics ◽  
Early Time ◽  
The Moon ◽  
Planetary Evolution ◽  
Planetary Geology ◽  
Lunar Science ◽  
The Earth ◽  
Celestial Bodies ◽  
The Subject ◽  
Impact Hypothesis

It seems anorthosites are by far interested by geologists because they give us great information about Earth history and how it was evolved in planetary geology. Planetary geology is subject the geology of the celestial bodies such as the planets and their moons, asteroids, comets, and meteorites. It is nearly abundant in the moon. So, it seems studying of these rocks give us good information about planetary evolution and the own early time conditions. Anorthosites can be divided into few types on earth such as: Archean-age (between 4,000 to 2,500 million years ago) anorthosites, Proterozoic (2.5 billion years ago) anorthosite (also known as massif or massif-type anorthosite) – the most abundant type of anorthosite on Earth, Anorthosite xenoliths in other rocks (often granites, kimberlites, or basalts). Furthermore, Lunar anorthosites constitute the light-colored areas of the Moon’s surface and have been the subject of much research. According to the Giant-impact hypothesis the moon and earth were both originated from ejecta of a collision between the proto-Earth and a Mars-sized planetesimal, approximately 4.5 billion years ago. The geology of the Moon (lunar science) is different from Earth. The Moon has a lower gravity and it got cooled faster due to its small size. Also, it has no plate tectonics and due to lack of a true atmosphere it has no erosion and weathering alike the earth. However, Eric A.K. Middlemost believed the astrogeology will help petrologist to make better petrogenic models to understand the magma changing process despite some terms geological differences among the Earth and other extraterrestrial bodies like the Moon. So, it seems that these future studies will clarify new facts about planet formation in planetary and earth, too.

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