scholarly journals D/H ratios of the inner Solar System

2017 ◽  
Vol 375 (2094) ◽  
pp. 20150390 ◽  
Author(s):  
L. J. Hallis
Keyword(s):  
Solar System ◽  
Giant Planet ◽  
Published Data ◽  
Solar System Formation ◽  
Atmospheric Processes ◽  
The Past ◽  
The Earth ◽  
Planetary Bodies ◽  
Original Water

The original hydrogen isotope (D/H) ratios of different planetary bodies may indicate where each body formed in the Solar System. However, geological and atmospheric processes can alter these ratios through time. Over the past few decades, D/H ratios in meteorites from Vesta and Mars, as well as from S- and C-type asteroids, have been measured. The aim of this article is to bring together all previously published data from these bodies, as well as the Earth, in order to determine the original D/H ratio for each of these inner Solar System planetary bodies. Once all secondary processes have been stripped away, the inner Solar System appears to be relatively homogeneous in terms of water D/H, with the original water D/H ratios of Vesta, Mars, the Earth, and S- and C-type asteroids all falling between δD values of −100‰ and −590‰. This homogeneity is in accord with the ‘Grand tack’ model of Solar System formation, where giant planet migration causes the S- and C-type asteroids to be mixed within 1 AU to eventually form the terrestrial planets. This article is part of the themed issue ‘The origin, history and role of water in the evolution of the inner Solar System’.

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 On the Role of the Earth-Moon System in the Stability of the Inner Solar System

1999 ◽  
Vol 117 (5) ◽  
pp. 2561-2562 ◽  
Author(s):  
F. Namouni ◽  
C. D. Murray
Keyword(s):  
Solar System ◽  
Moon System ◽  
The Earth ◽  
The Stability

scholarly journals (GTG)5-PCR Mediated Molecular Typing of Zoonotic Bacteria

2021 ◽  
Vol 11 (2) ◽  
pp. 279-283
Author(s):  
Daryoush Babazadeh ◽  
Reza Ranjbar
Keyword(s):  
Molecular Typing ◽  
Cost Effective ◽  
Present Review ◽  
Published Data ◽  
Bacterial Isolates ◽  
The Past ◽  
Virulent Strains ◽  
Pcr Method ◽  
Zoonotic Bacteria

The present review aimed to reveal the role of (GTG)5-PCR microbial typing in indicating the routes and source of infections, investigate the outbreaks and genotypes of clinical strains, as well as finding virulent strains and epidemiology of bacterial isolates. All available and published data in Google scholar, PubMed, ResearchGate, and Science Direct during the past two decades that used the (GTG)5-PCR method for genotyping the bacterial isolates were included in the current study. The findings have indicated that (GTG)5-PCR can be recommended as a possible, cost-effective, fast, and easy tool for molecular typing of bacterial isolates.

scholarly journals Jupiter – friend or foe? II: the Centaurs

2008 ◽  
Vol 8 (2) ◽  
pp. 75-80 ◽  
Author(s):  
J. Horner ◽  
B.W. Jones
Keyword(s):  
Solar System ◽  
Kuiper Belt ◽  
Giant Planet ◽  
Mass Extinctions ◽  
The Earth ◽  
Impact Rate ◽  
Short Period ◽  
Impact Risk ◽  
Life On Earth ◽  
The Impact

AbstractIt has long been assumed that the planet Jupiter acts as a giant shield, significantly lowering the impact rate of minor bodies upon the Earth, and thus enabling the development and evolution of life in a collisional environment which is not overly hostile. In other words, it is thought that, thanks to Jupiter, mass extinctions have been sufficiently infrequent that the biosphere has been able to diversify and prosper. However, in the past, little work has been carried out to examine the validity of this idea. In the second of a series of papers, we examine the degree to which the impact risk resulting from objects on Centaur-like orbits is affected by the presence of a giant planet, in an attempt to fully understand the impact regime under which life on Earth has developed. The Centaurs are a population of ice-rich bodies which move on dynamically unstable orbits in the outer Solar system. The largest Centaurs known are several hundred kilometres in diameter, and it is certain that a great number of kilometre or sub-kilometre sized Centaurs still await discovery. These objects move on orbits which bring them closer to the Sun than Neptune, although they remain beyond the orbit of Jupiter at all times, and have their origins in the vast reservoir of debris known as the Edgeworth–Kuiper belt that extends beyond Neptune. Over time, the giant planets perturb the Centaurs, sending a significant fraction into the inner Solar System where they become visible as short-period comets. In this work, we obtain results which show that the presence of a giant planet can act to significantly change the impact rate of short-period comets on the Earth, and that such planets often actually increase the impact flux greatly over that which would be expected were a giant planet not present.

The Accuracy of Radiocarbon Dates

Antiquity ◽  
1963 ◽  
Vol 37 (147) ◽  
pp. 213-219 ◽  
Author(s):  
W. F. Libby
Keyword(s):  
Magnetic Field ◽  
Solar System ◽  
Cosmic Ray ◽  
Average Life ◽  
Radiocarbon Dates ◽  
Cosmic Ray Intensity ◽  
Rapid Mixing ◽  
The Past ◽  
The Earth ◽  
The Magnetic Field

The first test of the accuracy of dates obtained by the radiocarbon technique was made by determining whether dates so obtained agreed with the historical dates for materials of known age (n. 1). The validity of the radiocarbon method continues to be an important question, especially in the light of the numerous results that have been accumulated and the greater precision of the technique during the past few years (n. 2).The radiocarbon content of the biosphere depends on three supposedly independent geophysical quantities: (i) the average cosmic ray intensity over a period of 8000 years (the average life of radiocarbon) as measured in our solar system but outside the earth's magnetic field (n. 1); (ii) the magnitude (but not the orientation, because of the relatively rapid mixing over the earth's surface) of the magnetic field in the vicinity of the earth, averaged over the same period (n. 1,3); and (iii) the degree of mixing of the oceans during the same period (n. 1). The question of the accuracy of radiocarbon dates therefore is of interest to geophysicists in general as well as to the archaeologists, geologists and historians who use the dates.Previous workers in this area (n. 1, 2) have reported some discrepancies, and it is the purpose here to consider the matter further.

USES AND ABUSES OF ANTIPYRETIC THERAPY

PEDIATRICS ◽  
1959 ◽  
Vol 23 (4) ◽  
pp. 774-780
Author(s):  
Alan K. Done
Keyword(s):  
Individual Case ◽  
Published Data ◽  
Common Symptom ◽  
Analgesic Drugs ◽  
The Past ◽  
Considerable Confusion ◽  
Mere Presence ◽  
Reduced Toxicity ◽  
The Individual

FEVER is undoubtedly the most common symptom confronting the physician who treats children. It is fought as though it were the patient's primary disease, and its mere presence is often accepted as being sufficient indication for the institution of antipyretic therapy. It is not surprising, therefore, that therapeutists and pharmaceutical concerns have energetically sought new and better drugs for the control of fever. In the past few years there has appeared on the market a number of new formulations which are purported to offer distinct advantages in terms of antipyretic potency, acceptance by children, and/or reduced toxicity. It is axiomatic that virtually any claim regarding a drug can be supported by published data, if the proper study is selected and interpretation is sufficiently influenced by conviction. Particularly is this true of antipyretic-analgesic drugs, where such factors as lability in the case of fever and lack of objectivity in the case of pain, make evaluation difficult. The claims and counterclaims which have been made concerning antipyretic drugs have led to considerable confusion and misunderstanding on the part of clinicians in general. The purpose of this presentation is to attempt to provide some clarification of this problem. IS ANTIPYRESIS INDICATED? More critical than the choice of an antipyretic is the question of whether or not such therapy is indicated in the individual case, for there is little doubt that these drugs are grossly overused, at times to the detriment of the patient. Therefore, before discussing the antipyretics themselves, it seems appropriate to review briefly a number of points which deserve consideration before one elects to use an antipyretic. DuBois summarized a lifetime of study on fever and the regulation of body temperature with the statement: "Fever is only a symptom and we are not sure that it is an enemy. Perhaps it is a friend." The literature concerning the possible role of fever in body defenses is extensive and inconclusive.

New Heavens, New Earth

Dark Skies ◽  
2020 ◽  
pp. 65-104
Author(s):  
Daniel Deudney
Keyword(s):  
Solar System ◽  
Human Life ◽  
Earth System ◽  
Human Control ◽  
The Past ◽  
The Earth ◽  
Orbital Space ◽  
The Many ◽  
Life On Earth ◽  
Modern Astronomy

Humans have always attributed enormous importance to occurrences in the heavens. Over the past several centuries modern astronomy has revealed a cosmos of staggering size, filled with trillions of worlds. Its vacuum, weightlessness, lethal radiations, and fantastic speeds make space harshly inhospitable to human life. To access orbital space requires velocities some thirty-four times as fast as jet aircraft, climbing out of steep gravity wells. Of the many bodies mapped by science in this solar system, asteroids are most practically important because they sometimes collide with great violence, profoundly shaping Earth’s deep history. As knowledge of the cosmos has grown, anticipations of nearby intelligent life have dramatically shrunk. The Space Age has also witnessed a far-reaching revolution in understanding the Earth System. Marked by complexity, chaos, and emergence, life on Earth is incompletely understood and inventoried and much less subject to human control than previously assumed, reducing the feasibility of expansionist visions.

scholarly journals The Role of Clouds in Brown Dwarf and Extrasolar Giant Planet Atmospheres

2004 ◽  
Vol 202 ◽  
pp. 269-276
Author(s):  
Mark S. Marley ◽  
Andrew S. Ackerman
Keyword(s):  
Remote Sensing ◽  
Solar System ◽  
Direct Detection ◽  
Giant Planet ◽  
Brown Dwarfs ◽  
Giant Planets ◽  
Brown Dwarf ◽  
L Dwarfs ◽  
Extrasolar Giant Planet

Clouds and hazes are important throughout our solar system and in the atmospheres of brown dwarfs and extrasolar giant planets. Among the brown dwarfs, clouds control the colors and spectra of the L-dwarfs; the disappearance of clouds helps herald the arrival of the T-dwarfs. The structure and composition of clouds will be among the first remote-sensing results from the direct detection of extrasolar giant planets.

Astromaterials Research of Comet Wild 2: Terameters to Nanometers

MRS Bulletin ◽  
2010 ◽  
Vol 35 (2) ◽  
pp. 150-154 ◽  
Author(s):  
Sean Brennan
Keyword(s):  
Solar System ◽  
Elemental Abundance ◽  
The Sun ◽  
Isotopic Abundance ◽  
Solar System Formation ◽  
Sample Return ◽  
X Ray ◽  
The Past ◽  
Cometary Material ◽  
Sample Return Mission

AbstractStardust, a NASA sample return mission, safely landed in the Utah desert in January 2006 after a seven-year mission, bringing with it the first cometary material from a known parent source, Comet 81P/Wild 2. One of the mission goals is to determine the starting material of the solar system. By sampling a comet, which has spent most of the past 4.6 Gyr beyond the orbit of Neptune, we expect to measure material presumed to be unaffected by the ignition of the sun. The Stardust spacecraft swept through the tail of the comet, collecting hundreds of micron-sized particles from that stream into aerogel, a low-density silica foam. An international team of materials scientists have studied the mineralogy, petrology, and elemental and isotopic abundance of these materials. Our group has studied elemental abundance using an x-ray microprobe; the morphology of the particles was examined using an x-ray microscope, which enables nanotomography of the particles while encased in aerogel. The unexpected conclusions are that much of the material from this comet was formed near the sun, after its ignition, and soon thereafter transported to the outer reaches of the solar system. These results have changed the way astrophysicists think about solar system formation.

scholarly journals On the Past, Present, and Future Role of Biology in NASA’s Exploration of our Solar System

2021 ◽  
Vol 53 (4) ◽  
Author(s):  
Kevin Hand ◽  
Cynthia B. Phillips ◽  
Christopher F. Chyba ◽  
Brandy Toner ◽  
Kakani Katija ◽  
...  
Keyword(s):  
Solar System ◽  
Future Role ◽  
The Past
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