Oxygen

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Scientific Evidence ◽  
Earth’S Atmosphere ◽  
The Earth ◽  
Evolution Of Life ◽  
History Of ◽  
Earth's Atmosphere ◽  
Book Covers ◽  
Over Time ◽  
The Way

The air we breathe is 21 percent oxygen, an amount higher than on any other known world. While we may take our air for granted, Earth was not always an oxygenated planet. How did it become this way? This book covers this vast history, emphasizing its relationship to the evolution of life and the evolving chemistry of the Earth. The book guides readers through the various lines of scientific evidence, considers some of the wrong turns and dead ends along the way, and highlights the scientists and researchers who have made key discoveries in the field. Showing how Earth's atmosphere developed over time, the book takes readers on a remarkable journey through the history of the oxygenation of our planet.

scholarly journals In-Situ Cosmogenic 14C: Production and Examples of its Unique Applications in Studies of Terrestrial and Extraterrestrial Processes

Radiocarbon ◽  
2001 ◽  
Vol 43 (2B) ◽  
pp. 731-742 ◽  
Author(s):  
D Lal ◽  
A J T Jull
Keyword(s):  
Half Life ◽  
Earth Science ◽  
Chemical Properties ◽  
Radioactive Isotopes ◽  
Earth’S Atmosphere ◽  
The Earth ◽  
Wide Range ◽  
History Of ◽  
Earth's Atmosphere

Nuclear interactions of cosmic rays produce a number of stable and radioactive isotopes on the earth (Lai and Peters 1967). Two of these, 14C and 10Be, find applications as tracers in a wide variety of earth science problems by virtue of their special combination of attributes: 1) their source functions, 2) their half-lives, and 3) their chemical properties. The radioisotope, 14C (half-life = 5730 yr) produced in the earth's atmosphere was the first to be discovered (Anderson et al. 1947; Libby 1952). The next longer-lived isotope, also produced in the earth's atmosphere, 10Be (half-life = 1.5 myr) was discovered independently by two groups within a decade (Arnold 1956; Goel et al. 1957; Lal 1991a). Both the isotopes are produced efficiently in the earth's atmosphere, and also in solids on the earth's surface. Independently and jointly they serve as useful tracers for characterizing the evolutionary history of a wide range of materials and artifacts. Here, we specifically focus on the production of 14C in terrestrial solids, designated as in-situ-produced 14C (to differentiate it from atmospheric 14C, initially produced in the atmosphere). We also illustrate the application to several earth science problems. This is a relatively new area of investigations, using 14C as a tracer, which was made possible by the development of accelerator mass spectrometry (AMS). The availability of the in-situ 14C variety has enormously enhanced the overall scope of 14C as a tracer (singly or together with in-situ-produced 10Be), which eminently qualifies it as a unique tracer for studying earth sciences.

9. A very brief history of the Earth

2018 ◽  
pp. 121-138
Author(s):  
Jan Zalasiewicz
Keyword(s):  
Earth’S Atmosphere ◽  
Organic Life ◽  
The Earth ◽  
History Of ◽  
Cenozoic Era ◽  
Earth's Atmosphere

Our planet is ancient—at 4.6 billion years—and over that time it has changed enormously. ‘A very brief history of the Earth’ describes how the Earth and Moon were created in the Chaotian Eon from the collision of two planets: Tellus and Theia. It outlines the heavy meteorite bombardment of the Hadean Eon; the Archean Eon (c.3.8 billion years ago) when rocks were first preserved; the arrival of oxygen in Earth’s atmosphere and explosion of organic life in the Proterozoic Eon; and the Phanerozoic Eon, in which we still live. The various eras of this eon are described: the Palaeozoic Era, the Mesozoic Era, and the Cenozoic Era.

History of the Earth’s Atmosphere

1987 ◽  
Author(s):  
Michael I. Budyko ◽  
Alexander B. Ronov ◽  
Alexander L. Yanshin
Keyword(s):  
Earth’S Atmosphere ◽  
History Of ◽  
Earth's Atmosphere

scholarly journals High-resolution spectroscopy and spectropolarimetry of the total lunar eclipse January 2019

2020 ◽  
Vol 635 ◽  
pp. A156
Author(s):  
K. G. Strassmeier ◽  
I. Ilyin ◽  
E. Keles ◽  
M. Mallonn ◽  
A. Järvinen ◽  
...  
Keyword(s):  
Large Scale ◽  
Solar Spectrum ◽  
High Resolution Spectroscopy ◽  
Strong Increase ◽  
Lunar Eclipse ◽  
The Sun ◽  
The Moon ◽  
Earth’S Atmosphere ◽  
The Earth ◽  
Earth's Atmosphere

Context. Observations of the Earthshine off the Moon allow for the unique opportunity to measure the large-scale Earth atmosphere. Another opportunity is realized during a total lunar eclipse which, if seen from the Moon, is like a transit of the Earth in front of the Sun. Aims. We thus aim at transmission spectroscopy of an Earth transit by tracing the solar spectrum during the total lunar eclipse of January 21, 2019. Methods. Time series spectra of the Tycho crater were taken with the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope in its polarimetric mode in Stokes IQUV at a spectral resolution of 130 000 (0.06 Å). In particular, the spectra cover the red parts of the optical spectrum between 7419–9067 Å. The spectrograph’s exposure meter was used to obtain a light curve of the lunar eclipse. Results. The brightness of the Moon dimmed by 10.m75 during umbral eclipse. We found both branches of the O2 A-band almost completely saturated as well as a strong increase of H2O absorption during totality. A pseudo O2 emission feature remained at a wavelength of 7618 Å, but it is actually only a residual from different P-branch and R-branch absorptions. It nevertheless traces the eclipse. The deep penumbral spectra show significant excess absorption from the Na I 5890-Å doublet, the Ca II infrared triplet around 8600 Å, and the K I line at 7699 Å in addition to several hyper-fine-structure lines of Mn I and even from Ba II. The detections of the latter two elements are likely due to an untypical solar center-to-limb effect rather than Earth’s atmosphere. The absorption in Ca II and K I remained visible throughout umbral eclipse. Our radial velocities trace a wavelength dependent Rossiter-McLaughlin effect of the Earth eclipsing the Sun as seen from the Tycho crater and thereby confirm earlier observations. A small continuum polarization of the O2 A-band of 0.12% during umbral eclipse was detected at 6.3σ. No line polarization of the O2 A-band, or any other spectral-line feature, is detected outside nor inside eclipse. It places an upper limit of ≈0.2% on the degree of line polarization during transmission through Earth’s atmosphere and magnetosphere.

The influence of scientific knowledge on mollusk and arthropod illustration

2021 ◽  
Author(s):  
Consuelo Sendino
Keyword(s):  
Nineteenth Century ◽  
Scientific Knowledge ◽  
Original Form ◽  
General Shape ◽  
New Techniques ◽  
History Of ◽  
Over Time ◽  
The Way

ABSTRACT Our attraction to fossils is almost as old as humans themselves, and the way fossils are represented has changed and evolved with technology and with our knowledge of these organisms. Invertebrates were the first fossils to be represented in books and illustrated according to their original form. The first worldwide illustrations of paleoinvertebrates by recognized authors, such as Christophorus Encelius and Conrad Gessner, considered only their general shape. Over time, paleoillustrations became more accurate and showed the position of organisms when they were alive and as they had appeared when found. Encyclopedic works such as those of the Sowerbys or Joachim Barrande have left an important legacy on fossil invertebrates, summarizing the knowledge of their time. Currently, new discoveries, techniques, and comparison with extant specimens are changing the way in which the same organisms are shown in life position, with previously overlooked taxonomically important elements being displayed using modern techniques. This chapter will cover the history of illustrations, unpublished nineteenth-century author illustrations, examples showing fossil reconstructions, new techniques and their influence on taxonomical work with regard to illustration, and the evolution of paleoinvertebrate illustration.

XXXIX.—Did the Tail of Halley's Comet affect the Earth's Atmosphere?

1910 ◽  
Vol 30 ◽  
pp. 529-550
Author(s):  
John Aitken
Keyword(s):  
The Sun ◽  
Earth’S Atmosphere ◽  
Magnetic Condition ◽  
The Earth ◽  
Electrical Condition ◽  
Halley's Comet ◽  
Earth's Atmosphere ◽  
Pass Through

The return of Halley's Comet in May of this year gave rise to much speculation as to its possible effects on the earth. As it was expected that the earth would pass through the tail of the comet when the comet passed between us and the sun, many observations were arranged for in order to see if the tail, whatever it was composed of, had any effect on the earth or on its atmosphere. If the tail was composed of matter in any form, gaseous, or fine solid or liquid particles, then it seemed possible to get some evidence of its presence in the atmosphere; or if the tail was composed of electrons, then these would disturb the electrical condition of the atmosphere, and also the magnetic condition of the earth.

History of the Earth's Atmosphere

Eos ◽  
1988 ◽  
Vol 69 (38) ◽  
pp. 869 ◽  
Author(s):  
Robert A. Berner
Keyword(s):  
Earth’S Atmosphere ◽  
History Of ◽  
Earth's Atmosphere
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