I.—On Aggregate Deposits, and their Relations to Zones

1898 ◽  
Vol 5 (11) ◽  
pp. 481-488
Author(s):  
J. F. Blake
Keyword(s):  
The Sun ◽  
Geological Time ◽  
The Earth ◽  
Rotation Of The Earth

Geological time, like all other kinds of time, can only be measured by the succession of events. If the events considered are constant in their recurrence and uniform in their nature, their number will afford the means of measuring the length of time. Thus the oscillations of a given pendulum, the rotation of the earth on its axis, and its revolution round the sun are sufficiently constant and uniform to afford a basis for our seconds, days, and years. Of such uniform and constantly recurring events geology affords no examples by which we could measure the length of geological time.

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 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.

scholarly journals On the Devonian age of the World

The Geologist ◽  
1861 ◽  
Vol 4 (8) ◽  
pp. 332-347
Author(s):  
W. Pengelly
Keyword(s):  
Thermal Conditions ◽  
The Sun ◽  
Geological History ◽  
Geological Time ◽  
The Earth ◽  
The World ◽  
Astronomical Time ◽  
History Of ◽  
Time Required ◽  
Devonian Age

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.

Astronomical Influences on Biomagnetic Activity Some 120 MA ago: the Potential for Estimating the Evolution of Ancient Planetary Orbits within the Solar System

1997 ◽  
Vol 161 ◽  
pp. 245-252
Author(s):  
Donald H. Tarling ◽  
Bruno D’argenio ◽  
Marina Iorio
Keyword(s):  
Magnetic Properties ◽  
Biological Activity ◽  
Solar System ◽  
Geomagnetic Field ◽  
Sedimentary Rocks ◽  
The Sun ◽  
The Earth ◽  
Geological Past ◽  
Planetary Orbits ◽  
Rotation Of The Earth

AbstractStudies of the magnetic properties of sedimentary rocks provide a record of biological activity in the geological past of the Earth. There is increasing evidence that the rate of biological activity reflects, in part, the direct and indirect influence of the Earth’s orbit around the Sun. These orbital changes also influence the strength and direction of the geomagnetic field, showing that orbital changes directly affect the processes generating the geomagnetic field. Therefore the presence of these effects means that past changes in the Earth’s orbit and the rate of rotation of the Earth can be investigated from such geological and geophysical records.

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.

scholarly journals Resonance in the perturbations of a synchronous satellite due to angular rate of the earth-moon system around the sun and the earth’s rotation rate

2016 ◽  
Vol 4 (2) ◽  
pp. 68
Author(s):  
Sushil Yadav ◽  
Rajiv Aggarwal ◽  
Bhavneet Kaur
Keyword(s):  
Rotation Rate ◽  
Angular Rate ◽  
Earth’S Rotation ◽  
The Sun ◽  
Earth's Rotation ◽  
Moon System ◽  
The Earth ◽  
Time Period ◽  
Rotation Of The Earth ◽  
Small Change

This paper investigates resonances in the perturbations of a synchronous satellite including its latitude, angular rate of the earth-moon system around the sun and the earth’s rotation rate about its axis. This is found that resonances occur due to the commensurability between (i) angular velocity of the satellite and angular rate of earth’s rotation about its axis and (ii) angular rate of the earth-moon system around the sun and angular rate of the rotation of the earth. Amplitude and time-period of the oscillation at the resonance points are determined using the procedure of Brown and Shook [3]. Effect of  (orbital angle of the mass-centre of the earth-moon system around the sun) on amplitude and time period is also analyzed. It is found that for increasing the values of  from to  amplitude decreases and time period also decreases. Effect of time on the latitude of the satellite including earth oblateness is also studied. It is seen that for increasing the value of , there is a small change in ,  the latitude of the synchronous satellite.

scholarly journals On the nonlinear and Solar-forced nature of the Chandler wobble in the Earth's pole motion

2019 ◽  
Author(s):  
Dmitry M. Sonechkin
Keyword(s):  
Solar Activity ◽  
Activity Index ◽  
Nonlinear Differential Equations ◽  
Harmonic Oscillation ◽  
Chandler Wobble ◽  
The Sun ◽  
Solar Activity Index ◽  
The Earth ◽  
Rotation Of The Earth

Abstract. About 250 years ago L. Euler has derived a system of three quadratic-nonlinear differential equations to depict the rotation of the Earth as a rigid body. Neglecting a small distinction between the equatorial inertia moments, he reduced this system to much simpler linear one, and concluded that the Earth's pole must experience a harmonic oscillation of the 304-day period. Astronomers could not find this oscillation, but instead, S.C Chandler has found two powerful wobbles with the 12- and ~ 14-month periods in reality. Adhering to the Euler's linearization, astronomers can not explain the nature of the later wobble up to now. I indicate that the neglect by the above small distinction (“a small parameter” of the Euler's primary nonlinear equations) is not admissible because the effect of this parameter is singular. Analysing the primary equations by an asymptotic technique, I demonstrate that the Chandler wobble tones are formed from combinational harmonics of the Euler's 304-day oscillation, long-term Luni-Solar tides as well as the 22-year cycle of the heliomagnetic activity. Correlating simultaneous variations of the wobble and a solar activity index, I corroborate that the Chandler wobble is really affected by the Sun.

scholarly journals Heraclides of Pontus. Astronomical fragments

2019 ◽  
Vol 13 (2) ◽  
pp. 740-754
Keyword(s):  
The Sun ◽  
Maximum Elongation ◽  
Philosophy Of Nature ◽  
Literary Genres ◽  
The Earth ◽  
Literature History ◽  
Rotation Of The Earth ◽  
Evening Star ◽  
Diurnal Rotation

Heraclides of Pontus (c. 388–310 BCE), a Platonic philosopher, worked in various literary genres and wrote on such topics as psychology, politics, literature, history, geography, astronomy and the philosophy of nature. Nothing is preserved. The present publication contains a collection of the testimonies about Heraclides’ astronomical writings. He thought of an infinite universe, in fact believing that every star is a kosmos, located in the infinite either. He famously advanced the theory of terrestrial rotation, hypothesizing that the apparent diurnal rotation of the heavens is better explained by the rotation of the Earth, and in this context correctly observed that, unlike other planets, Venus as morning and evening star has the maximum elongation from the Sun’s position (that is to say is never located far from the Sun). The evidences are translated and numbered according to a new edition by Schütrumpf et al. 2008.

VII.—Radium and the Radial Shrinkage of the Earth

1906 ◽  
Vol 3 (2) ◽  
pp. 79-80
Author(s):  
T. Mellard Reade
Keyword(s):  
South African ◽  
Small Proportion ◽  
Presidential Address ◽  
British Association ◽  
The Sun ◽  
Geological Time ◽  
Active Materials ◽  
The Earth ◽  
Radial Shrinkage

IN his Presidential Address to the British Association, South African Meeting, 1905, Professor G. H. Darwin points out that the presence of radio-active materials in small proportion in the sun would serve to explain the present radiation, and “that concentration of matter is not the only source from which the sun may draw its heat.” Professor Darwin goes on to explain how this enables us to extend the possibilities of geological time beyond that to which some physicists would limit us.

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