Time and The Royal Society

2001 ◽  
Vol 55 (1) ◽  
pp. 9-27
Author(s):  
A. Cook
Keyword(s):  
Royal Society ◽  
Frequency Standard ◽  
National Physical Laboratory ◽  
The Sun ◽  
The Earth ◽  
Physical Laboratory ◽  
Astronomical Time ◽  
Rotation Of The Earth ◽  
Lord Kelvin ◽  
Atomic Time

Fellows of The Royal Society have been concerned with the definition and measurement of time from the first days of the Society. John Flamsteed, F.R.S., ‘Royal Astronomer’, showed that the rotation of the Earth was isochronous and that the length of the solar day varied with the season because the path of the Earth about the Sun was an ellipse inclined to the Equator of the Earth. In the 20th century, D.W. Dye, F.R.S., made quartz oscillators that replaced mechanical clocks, and L. Essen, F.R.S., brought into use at the National Physical Laboratory the first caesium beam frequency standard and advocated that atomic time should replace astronomical time as the standard. The Society supported the development of chronometers for use at sea to determine longitude, and Fellows used the electric telegraph to find longitude in India. Edmond Halley, F.R.S., estimated the age of the Earth from the saltiness of lakes and seas; Lord Kelvin, F.R.S., estimated the rate at which energy was being radiated from the Sun; and Lord Rutherford, F.R.S., showed how the ages of rocks and of the Earth could be found from decay of radioactive minerals in them.

Variations in rotation of the earth, results obtained with the dual-rate moon camera and photographic zenith tubes

1959 ◽  
Vol 11 ◽  
pp. 26-33
Author(s):  
Wm. Markowitz
Keyword(s):  
Seasonal Variation ◽  
Research Laboratory ◽  
Quartz Crystal ◽  
National Physical Laboratory ◽  
Naval Research ◽  
Love Number ◽  
The Earth ◽  
Physical Laboratory ◽  
Rotation Of The Earth ◽  
Irregular Variation

Comparison of photographic zenith tube (P.Z.T.) observations with time derived from quartz-crystal clocks during 1951 to 1955 and with cesium standards of frequency during 1955 to 1958 indicates that the seasonal variation is nearly the same from year to year. Lunar-tidal inequalities of semi-monthly and monthly periods with amplitudes of about 0S.001 each were found. A preliminary value of the Love number, k, is derived. Observations made since 1952 with the dual-rate moon position camera are used to derive ΔT = ET – UT. Comparison of the P.Z.T. observations and atomic standards at the National Physical Laboratory and the Naval Research Laboratory shows details of the irregular variation from 1955 to 1958.

Conversaziones 1958

1958 ◽  
Vol 13 (2) ◽  
pp. 75-81
Keyword(s):  
Royal Society ◽  
Nuclear Power ◽  
National Physical Laboratory ◽  
Radio Emissions ◽  
Power Stations ◽  
Flexible Films ◽  
The Earth ◽  
Physical Laboratory ◽  
Accuracy Of Measurement ◽  
Topical Interest

Conversaziones were held this year on 15 May and 26 June, and in addition there was a further special conversazione on 15 July to celebrate the Darwin-Wallace centenary. An account of this special conversazione will be found on page 73. At the first conversazione, on 15 May, there were 27 exhibits and a film. An exhibit of much topical interest was that prepared by members of the Royal Society W orking Party on Radio Emissions from Earth Satellites, which showed how the tracks of the Russian earth satellites were plotted. The orbit of such a satellite is nearly, but not quite, fixed in space, and the earth rotates inside the orbit. Observations were made by both radio and radar, and much information about the ionosphere and upper atmosphere was obtained from the analysis of changes in the shape and position o f the satellites’ orbits. Dr J. C. Evans and Mr I. G. Morgan, Metrology Division, National Physical Laboratory, Teddington, exhibited a pneumatic instrument for accurately measuring the thickness of flexible films. Use of a pneumatic technique for this purpose has the advantage that the film is not compressed or in any way distorted while measurement of its thickness is being made, and results of an accuracy of the order of ± 10 micro-inches can be obtained. An exhibit on the properties of circular diffraction gratings was arranged by the Optical Section of the Research Laboratories of Associated Electrical Industries Ltd., Aldermaston. Particular emphasis was given to the ways in which such gratings may be used to measure straightness, which can be ascertained, by this means, to an accuracy of about in. per mile. Such minute accuracy of measurement has important technical applications, such as in the alignment of the bearings of the very large turbo-alternators now being built for nuclear power stations.

scholarly journals Seasonal variations and north–south asymmetries in polar wind outflow due to solar illumination

2016 ◽  
Vol 34 (11) ◽  
pp. 961-974 ◽  
Author(s):  
Lukas Maes ◽  
Romain Maggiolo ◽  
Johan De Keyser
Keyword(s):  
Seasonal Variations ◽  
Solar Zenith Angle ◽  
The Sun ◽  
Polar Ionosphere ◽  
Polar Cap ◽  
Polar Wind ◽  
Simple Set ◽  
The Earth ◽  
Rotation Of The Earth ◽  
Set Up

Abstract. The cold ions (energy less than several tens of electronvolts) flowing out from the polar ionosphere, called the polar wind, are an important source of plasma for the magnetosphere. The main source of energy driving the polar wind is solar illumination, which therefore has a large influence on the outflow. Observations have shown that solar illumination creates roughly two distinct regimes where the outflow from a sunlit ionosphere is higher than that from a dark one. The transition between both regimes is at a solar zenith angle larger than 90°. The rotation of the Earth and its orbit around the Sun causes the magnetic polar cap to move into and out of the sunlight. In this paper we use a simple set-up to study qualitatively the effects of these variations in solar illumination of the polar cap on the ion flux from the whole polar cap. We find that this flux exhibits diurnal and seasonal variations even when combining the flux from both hemispheres. In addition there are asymmetries between the outflows from the Northern Hemisphere and the Southern Hemisphere.

scholarly journals XXXIV. On the transit of Venus in 1769. To the Right Honourable The Earl of Morton, President to the Council and Fellows of the Royal Society, this discourse is, with all humility, inscribed, by their humble servant, Thomas Hornsby

1765 ◽  
Vol 55 ◽  
pp. 326-344 ◽  
Keyword(s):  
Royal Society ◽  
The Sun ◽  
The Real ◽  
The Earth ◽  
Theory Of Gravity ◽  
The Right ◽  
Made In

The observations of the late transit of Venus, though made with all possible care and accuracy, have not enabled us to determine with certainty the real quantity of the sun's parallax; since, by a comparison of the observations made in several parts of the globe, the sun's parallax is not less than 8" 1/2, nor does it seem to exceed 10". From the labours of those gentlemen, who have attempted to deduce this quantity from the theory of gravity, it should seem that the earth performs its annual revolution round the sun at a greater distance than is generally imagined: since Mr. Professor Stewart has determined the sun's parallax to be only 6', 9, and Mr. Mayer, the late celebrated Professor at Gottingen, who hath brought the lunar tables to a degree of perfection almost unexpected, is of opinion that it cannot exceed 8".

scholarly journals Solar Tracker

2020 ◽  
Vol 2 (1) ◽  
pp. 59-65
Author(s):  
Irfan Danial Hashim ◽  
Ammar Asyraf Ismail ◽  
Muhammad Arief Azizi
Keyword(s):  
Fossil Fuels ◽  
Electrical Energy ◽  
Maximum Amount ◽  
Solar Panel ◽  
Angle Of Incidence ◽  
The Sun ◽  
Continuous Change ◽  
The Earth ◽  
Solar Tracker ◽  
Rotation Of The Earth

Solar Tracker The generation of power from the reduction of fossil fuels is the biggest challenge for the next half century. The idea of converting solar energy into electrical energy using photovoltaic panels holds its place in the front row compared to other renewable sources. But the continuous change in the relative angle of the sun with reference to the earth reduces the watts delivered by solar panel. Conventional solar panel, fixed with a certain angle, limits their area of exposure from the sun due to rotation of the earth. Output of the solar cells depends on the intensity of the sun and the angle of incidence. To solve this problem, an automatic solar cell is needed, where the Solar Tracker will track the motion of the sun across the sky to ensure that the maximum amount of sunlight strikes the panels throughout the day. By using Light Dependent Resistors, it will navigate the solar panel to get the best angle of exposure of light from the sun.

Addendum 2020 to ‘Measurement of the Earth’s rotation: 720 BC to AD 2015’

2021 ◽  
Vol 477 (2246) ◽  
pp. 20200776
Author(s):  
L. V. Morrison ◽  
F. R. Stephenson ◽  
C. Y. Hohenkerk ◽  
M. Zawilski
Keyword(s):  
Angular Momentum ◽  
Earth’S Rotation ◽  
The Sun ◽  
Earth's Rotation ◽  
Moon System ◽  
Link Type ◽  
The Earth ◽  
Solar Eclipses ◽  
Rotation Of The Earth

Historical reports of solar eclipses are added to our previous dataset (Stephenson et al. 2016 Proc. R. Soc. A 472 , 20160404 ( doi:10.1098/rspa.2016.0404 )) in order to refine our determination of centennial and longer-term changes since 720 BC in the rate of rotation of the Earth. The revised observed deceleration is −4.59 ± 0.08 × 10 −22  rad s −2 . By comparison the predicted tidal deceleration based on the conservation of angular momentum in the Sun–Earth–Moon system is −6.39 ± 0.03 × 10 −22  rad s −2 . These signify a mean accelerative component of +1.8 ± 0.1 × 10 −22  rad s −2 . There is also evidence of an oscillatory variation in the rate with a period of about 14 centuries.

I.—Lord Kelvin: A Centenary Tribute

1926 ◽  
Vol 45 (1) ◽  
pp. 1-2
Author(s):  
J. Alfred Ewing
Keyword(s):  
Royal Society ◽  
World Wide ◽  
Vortex Motion ◽  
Dynamical Theory ◽  
Dissipation Of Energy ◽  
The Earth ◽  
Molecular Constitution ◽  
Lord Kelvin

In this the centenary year of Lord Kelvin's birth it is fitting that the Society should call to remembrance one who was for long its most distinguished Fellow, who first became its President at the age of thirty-nine, and was repeatedly re-elected to the office, which he held for twenty-one years in all, and who used the Society as a medium for the publication of many of his most brilliant discoveries. In the long list of his published papers there are at least one hundred and twenty items communicated to the Royal Society of Edinburgh. No other contributor has done so much to give to our Proceedings and Transactions a world-wide and lasting fame. It was to this Society that he brought, in 1849, his account of Carnot's Theory, which marks the beginning of his study of Thermodynamics, and it was in our Transactions that he published his epochmaking series of papers on the “Dynamical Theory of Heat” from 1851 to 1854. It was here in 1852 that he propounded the doctrine of the Dissipation of Energy. It was here that his investigations of underground temperature and the secular cooling of the Earth appeared in 1860 and 1862. It was here in 1865 that he “briefly refuted” the doctrine of Uniformity in Geology. Here, too, were published his long series of papers on Vortex Motion and Vortex Atoms, from 1867 to 1881, and much of his work on the molecular constitution of matter. Here he first showed, in germ, his mariner's compass, in 1874.

“ Ten Years' Testing of Model Seaplanes ”

1923 ◽  
Vol 27 (149) ◽  
pp. 224-243
Author(s):  
G. S. Baker
Keyword(s):  
Experimental Work ◽  
Royal Society ◽  
General Meeting ◽  
National Physical Laboratory ◽  
The Other ◽  
Experimental Tank ◽  
Know How ◽  
Other Hand ◽  
Physical Laboratory ◽  
Hull Design

An Ordinary General Meeting- of the Society was held at the Royal Society of Arts, on Thursday, February ist, 1923, Professor L. Bairstow in the chair.The Chairman, in opening- the proceedings, said that Mr. G. S. Baker, O.B.E., of the National Physical Laboratory, would deal with flying boats and seaplanes. He would deal with the hull and its design, that part of the seaplane which differentiates it from the aeroplane. That subject had been touched on very lightly by Major Rennie at the previous meeting of the Society, in view of the present paper by Mr. Baker.Mr. Baker had begun work in 1912 on the problems of hull design, at a time when nothing of a definite nature was known; a few individual experiments had been carried out, but there was no systematised knowledge at all at that time. From that state of ignorance a great deal of experimental work had now rescued us. He did not know how far Mr. Baker would stress the point, but it was quite clear, from the investigation of certain accidents to seacraft, that there were fundamental differences in the behaviour of seaplane hulls on the water, differences which had a great deal of effect on the risk of flying-. For instance, if one type of hull was such that when the plane rose in the air it stalled, then all the aerodynamical consequences of stalling- followed, and there was difficulty. On the other hand, it appeared that we had a type of flying- boat which did not make the plane stall on getting into the air, and consequently if it came back to the water it was still controlled. For this type of development, which he believed really dated back to the C.E.i, we were mainly indebted to Mr. Baker and his associates at the National Physical Laboratory, and to the generosity of Sir Alfred Yarrow in placing such a magnificent piece of apparatus as the experimental tank at the disposal of the nation.Mr. Baker then read his paper on “ Ten Years’ Testing of Model Seaplanes.”

scholarly journals VII. Note on 'spectroscopic papers'

1879 ◽  
Vol 29 (196-199) ◽  
pp. 166-168
Keyword(s):  
Royal Society ◽  
Wave Length ◽  
The Sun ◽  
Decimal Point ◽  
The Earth

In a recent communication to the Royal Society, Mr. Lockyer has criticised our statement of Young’s wave-length identifications of certain chromospheric lines. As to the wave-length, we have throughout our table omitted all figures after the decimal point merely for the sake of not cumbering the table. The numbers, Young tells us, are not his own, but taken from Ǻngström’s catalogue. Moreover, as to Young’s identifications with metallic lines, he states expressly that they were taken from the maps of Kirchhoff, Ǻngström, and Thalén, and Watts’s “Index of Spectra.” But our object was not to criticise Young’s work, but only to use it for the purpose of comparing the behaviour of certain metals on the earth and in the sun, and the conditions under which certain lines appear, or do not appear, or are reversed.

III. On Fessel's gyroscope

1856 ◽  
Vol 7 ◽  
pp. 43-48
Keyword(s):  
Royal Society ◽  
Rotary Motion ◽  
The Earth ◽  
Rotation Of The Earth ◽  
Mechanical Proof ◽  
Present Opportunity

Since the announcement of M. Foucault’s beautiful experiment which has afforded us a new mechanical proof of the rotation of the earth on its axis, the phenomena of rotary motion have received renewed attention, and many ingenious instruments have been contrived to exhibit and to explain them. One of the most instructive of these is the Gyroscope invented by M. Fessel of Cologne, described in its earlier form in Poggendorff’s Annalen for September 1853, and which, with some improvements by Prof. Plücker and some further modifications suggested by myself, I take the present opportunity of bringing before the Royal Society.

Sign in / Sign up

Export Citation Format

Share Document