scholarly journals II. On the relations of the secular variation of the magnetic declination and inclination at London, Cape of Good Hope, St. Helena and Ascension Island, as exhibited on the magnetarium

1894 ◽  
Vol 55 (331-335) ◽  
pp. 210-217 ◽  
Keyword(s):  
Experimental Science ◽  
Cape Of Good Hope ◽  
The Earth ◽  
Magnetic Elements ◽  
Ascension Island ◽  
Secular Variations ◽  
Short Period ◽  
St Helena ◽  
Northern And Southern Hemispheres ◽  
Diurnal Rotation

In a paper which was read before the Royal Society in June, 1890, I showed that the principal phenomena of terrestrial magnetism and the secular changes in its horizontal and vertical components could be explained on the assumption of an electro-dynamic substance (presumably liquid or gaseous) rotating within the crust of the earth in the plane of the ecliptic, and a little slower than the diurnal rotation. By means of some electro-mechanism, new to experimental science, which I termed a magnetarium, the period of backward rotation of the internal electro-dynamic sphere required for the secular variations of the magnetic elements on different parts of the earth’s surface was found to be 960 years, or 22.5 minutes of a degree annually. It was also demonstrated that the inclination of the axes of the electro-dynamic and terrestrial globes to each other of 20° 30', was the cause of the inequality of the declination periods about the same meridian in the northern and southern hemispheres; as instanced in the short period of outward westerly declination at London, and the long period of outward westerly declination at the Cape of Good Hope and St. Helena.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

scholarly journals New Tools for the Optimized Follow-Up of Imminent Impactors

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Maddalena Mochi ◽  
Giacomo Tommei
Keyword(s):  
Orbit Determination ◽  
Main Belt ◽  
Impact Monitoring ◽  
The Earth ◽  
Current Observation ◽  
Short Period ◽  
Fly Eye ◽  
Near Earth Asteroids ◽  
Near Earth Objects

The solar system is populated with, other than planets, a wide variety of minor bodies, the majority of which are represented by asteroids. Most of their orbits are comprised of those between Mars and Jupiter, thus forming a population named Main Belt. However, some asteroids can run on trajectories that come close to, or even intersect, the orbit of the Earth. These objects are known as Near Earth Asteroids (NEAs) or Near Earth Objects (NEOs) and may entail a risk of collision with our planet. Predicting the occurrence of such collisions as early as possible is the task of Impact Monitoring (IM). Dedicated algorithms are in charge of orbit determination and risk assessment for any detected NEO, but their efficiency is limited in cases in which the object has been observed for a short period of time, as is the case with newly discovered asteroids and, more worryingly, imminent impactors: objects due to hit the Earth, detected only a few days or hours in advance of impacts. This timespan might be too short to take any effective safety countermeasure. For this reason, a necessary improvement of current observation capabilities is underway through the construction of dedicated telescopes, e.g., the NEO Survey Telescope (NEOSTEL), also known as “Fly-Eye”. Thanks to these developments, the number of discovered NEOs and, consequently, imminent impactors detected per year, is expected to increase, thus requiring an improvement of the methods and algorithms used to handle such cases. In this paper we present two new tools, based on the Admissible Region (AR) concept, dedicated to the observers, aiming to facilitate the planning of follow-up observations of NEOs by rapidly assessing the possibility of them being imminent impactors and the remaining visibility time from any given station.

scholarly journals Self-Organization of Water Molecules Over 11-Year Solar Cycle

2021 ◽  
Author(s):  
Igor Shevchenko
Keyword(s):  
Solar Activity ◽  
Water Clusters ◽  
The Self ◽  
Self Organization ◽  
Water Molecules ◽  
Annual Variations ◽  
The Earth ◽  
Rate Of Hydrolysis ◽  
Rotation Of The Earth ◽  
Northern And Southern Hemispheres

Abstract The variations of solar activity and distribution of solar energy due to the rotation of the Earth around its axis and around the Sun exert a strong influence on the self-organization of water molecules. As a result, the rate of hydrolytic processes with the participation of water clusters displays diurnal, very large annual variations, and is also modulated by the 11-year cycles of solar activity. It also depends on the geographic latitude and can be different at the same time in the Northern and Southern Hemispheres. This phenomenon is well accounted for by the influence of muons on the self-organization of water molecules. Muons are constantly generated in the upper atmosphere by the solar wind. They reach the surface of the Earth and can penetrate to some depth underground. Buildings also absorb muons. For this reason, the rate of hydrolysis outside and inside buildings, as well as underground, can differ significantly from each other.

scholarly journals Radar Observations of Comet Nuclei and Comae

2005 ◽  
Vol 13 ◽  
pp. 763-763
Author(s):  
Donald B. Campbell ◽  
John K. Harmon ◽  
Micael C. Nolan ◽  
Steven J. Ostro
Keyword(s):  
Cross Sections ◽  
Cometary Nucleus ◽  
Size Distributions ◽  
Radar Systems ◽  
The Earth ◽  
Radar Cross Sections ◽  
Short Period ◽  
Grain Size Distributions ◽  
Resolution Imaging

Nine comets have been detected with either the Arecibo (12.6 cm wavelength) or Goldstone (3.5 cm) radar systems. Included are six nucleus detections and five detections of echoes from coma grains. The radar backscatter cross sections measured for the nuclei correlate well with independent estimates of their sizes and are indicative of surface densities in the range of 0.5 to 1.0 g cm-3. Like most asteroids, comets appear to have surfaces that are very rough at scales much larger than the radar wavelength. Coma echo models can explain the radar cross sections using grain size distributions that include a substantial population of cm-sized grains. A long term goal of the cometary radar program has been the high resolution imaging of a cometary nucleus. Eleven short period comets are potentially detectable over the next two decades a few of which may be suitable for imaging. We are always waiting for the arrival of a new comet with an orbit that brings it within 0.1 AU of the earth.

The strength of the Earth’s magnetic field from Pre-Pottery to Pottery Neolithic, Jordan

2021 ◽  
Author(s):  
Anita Di Chiara ◽  
Lisa Tauxe ◽  
Thomas Levy ◽  
Mohammand Najjar ◽  
Fabio Florindo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Dipole Moments ◽  
Ancient Egypt ◽  
Archaeological Sites ◽  
Southern Levant ◽  
Short Term ◽  
The Past ◽  
The Earth ◽  
Secular Variations ◽  
Geological Formations

<p>Constraining the secular variations of the Earth’s magnetic field strength in the past is fundamental to understanding short term processes of the geodynamo. Such records constitute a powerful and independent dating tool for archaeological sites and geological formations. In this study, we present 10 new and robust archaeointensity results from Pre-Pottery to Pottery Neolithic and, for one of the first times, flint (burnt chert) from Jordan. Two of these results constitute the oldest archaeointensity data for the entire Levant, ancient Egypt and Mesopotamia extending the archaeomagnetic dating reference for the Holocene. Virtual Axial Dipole Moments (VADM)s show that the Earth’s magnetic field in the Southern Levant was weak (about half the present field) at around 7,600 years BCE, recovering its strength to greater than the present field around 7,100 BCE and gradually weakening again around 5,200 years BCE. In addition, successful results obtained from burnt flint demonstrate the potential of this rarely used material in archaeomagnetic research, in particular for prehistoric periods from the first use of fire to the invention of pottery.</p>

scholarly journals Investigation of the Orbital Stability of Minor Planets with Cometary Eccentricities

1972 ◽  
Vol 45 ◽  
pp. 431-436 ◽  
Author(s):  
G. A. Chebotarev ◽  
N. A. Belyaev ◽  
R. P. Eremenko
Keyword(s):  
Orbital Stability ◽  
Minor Planets ◽  
The Earth ◽  
Short Period ◽  
Account Information

The evolution of the orbits of 19 asteroids of particular interest has been studied over the interval 1660–2060, perturbations by Venus to Pluto being taken into account. Information was obtained about the encounters with Venus, the Earth, and Mars. A few approaches of Hidalgo to Jupiter were noted. In distinction to the orbits of short-period comets, the orbits of the 19 asteroids are stable throughout the 400-yr interval.

scholarly journals On a collection of caridean shrimps (Decapoda, Caridea) from St. Helena, south-central Atlantic, with further records from Ascension Island

Crustaceana ◽  
2019 ◽  
Vol 92 (7) ◽  
pp. 869-879
Author(s):  
Sammy De Grave ◽  
Judith Brown ◽  
Peter Wirtz ◽  
Arthur Anker
Keyword(s):  
Atlantic Ocean ◽  
Endemic Species ◽  
The South ◽  
Number Of Species ◽  
South Central ◽  
Ascension Island ◽  
Recent Collection ◽  
St Helena ◽  
Central Atlantic

Abstract We report on a recent collection of caridean shrimps from St. Helena in the south-central Atlantic Ocean, raising the total number of species known from the island to 24. Six species are newly recorded for the area, with no endemic species present. Additional three species are recorded from Ascension Island. A close biogeographical connection between the caridean faunas of St. Helena and Ascension Island is evident.

scholarly journals The Period of Organization of the International Latitude Service: 1889–1899

2000 ◽  
Vol 178 ◽  
pp. 121-138
Author(s):  
E. Proverbio
Keyword(s):  
Principal Axis ◽  
Rotation Axis ◽  
Systematic Errors ◽  
Rotational Axis ◽  
The Earth ◽  
Secular Variations ◽  
Relative Motions

Around 1880, and for some time after that, the possibility of revealing a variation in latitude as a consequence of a separation of the instantaneous rotation axis from the Earth’s axis of inertia gave rise to much perplexity due to the complexity of the problem and the existence of non-negligible and hard-to-find systematic errors in observations of a personal and instrumental nature. These errors also depended on effects of refraction and imprecise knowledge of star declinations.To this must be added the fact that the very idea that the rotational axis and the axis of inertia were distinct and in relative motions raised difficult problems of a physical and theoretical nature. At that time the idea of the Earth’s rigidity was still generally accepted and, even admitting the hypothesis of an Earth endowed with sufficient elasticity and plasticity, the theory of which had been partly examined by G.H. Darwin, it was then almost impossible, just as it still is today, to create a model of the movements of mass inside the Earth which could offer an explanation of possible aperiodic and secular variations. In reality, more than on the existence of periodic variations, the attention and interest of geodesists and astronomers was in those years focused on the problem of the existence or non-existence of secular variations in the Earth’s principal axis.

I. On local magnetic disturbance in Islands situated far from a continent

1886 ◽  
Vol 40 (242-245) ◽  
pp. 83-93
Keyword(s):  
Magnetic Disturbance ◽  
British Government ◽  
Magnetic Attraction ◽  
Magnetic Elements ◽  
St Helena

It has been known for many years past that in the islands of St. Helena and Ascension observations of the three magnetic elements made at different stations gave remarkably divergent results, caused by some undefined local magnetic attraction. Thus in the observations at St. Helena, carried out under the auspices of the British Government in 1840-46, it was found that the observed inclination and intensity differed considerably at the two stations of Longwood and Sister’s Walk, 2½ miles apart, and these again differed from those made on board ships in the anchorage.

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