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G. Randall Gladstone

Bio: G. Randall Gladstone is an academic researcher from Southwest Research Institute. The author has contributed to research in topics: Jupiter & Atmosphere. The author has an hindex of 28, co-authored 108 publications receiving 3309 citations. Previous affiliations of G. Randall Gladstone include California Institute of Technology & University of Texas at San Antonio.
Topics: Jupiter, Atmosphere, Spectrograph, Jovian, Pluto


Papers
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Journal ArticleDOI
01 Feb 2000-Icarus
TL;DR: In this paper, a diurnally averaged model that couples hydrocarbon and oxygen photochemistry, molecular and eddy diffusion, radiative transfer, and condensation was developed to investigate the details of hydrocarbon photochemistry on Saturn, and the model results are compared with observations from the Infrared Space Observatory (ISO) to place tighter constraints on molecular abundances, to better define Saturn's eddy coefficient profile, and to identify important chemical schemes that control the abundances of the observable hydrocarbons in Saturn's upper atmosphere.

293 citations

Journal ArticleDOI
01 Jan 1996-Icarus
TL;DR: There is a great need for laboratory measurements of basic reaction rates and photodissociation quantum yields, even for such simple species as methylacetylene and allene, until such laboratory measurements exist there will be considerable uncertainty in the understanding of the C3 and higher hydrocarbons in the atmospheres of the jovian planets.

269 citations

Journal ArticleDOI
10 Oct 1980-Science
TL;DR: Subsequent reactions of formaldehyde in primeval aquatic environments would have implications for the abiotic synthesis of complex organic molecules and the origin of life.
Abstract: Formaldehyde could have been produced by photochemical reactions in Earth's primitive atmosphere, at a time when it consisted mainly of molecular nitrogen, water vapor, carbon dioxide, and trace amounts of molecular hydrogen and carbon monoxide. Removal of formaldehyde from the atmosphere by precipitation can provide a source of organic carbon to the oceans at the rate of 10(11) moles per year. Subsequent reactions of formaldehyde in primeval aquatic environments would have implications for the abiotic synthesis of complex organic molecules and the origin of life.

230 citations

Journal ArticleDOI
01 May 2000-Icarus
TL;DR: In this paper, a diurnally averaged model of photochemistry and diffusion in the stratosphere of Saturn's stratosphere was used to investigate the influence of extraplanetary debris on atmospheric chemistry, in particular the effects of an influx of oxygen from micrometeoroid ablation or from ring-particle diffusion.

166 citations

Journal ArticleDOI
TL;DR: A review of the development of our current understanding of auroral emissions from Jupiter, Saturn, Uranus, and Neptune, as revealed through multispectral observations and supplemented by plasma measurements can be found in this paper.
Abstract: Auroras are (generally) high-latitude atmospheric emissions that result from the precipitation of energetic charged particles from a planet's magnetosphere. Auroral emissions from the giant planets have been observed from ground-based observatories, Earth-orbiting satellites (e.g., International Ultraviolet Explorer (IUE), Hubble Space Telescope (HST), and Roentgensatellit (ROSAT)), flyby spacecraft (e.g., Voyager 1 and 2), and orbiting spacecraft platforms (e.g., Galileo) at X-ray, ultraviolet (UV), visible, infrared (IR), and radio wavelengths. UV, visible, and IR auroras are atmospheric emissions, produced or initiated when ambient atmospheric species are excited through collisions with the precipitating particles, while radio and X-ray auroras are beam emissions, produced by the precipitating species themselves. The emissions at different wavelengths provide unique and complementary information, accessible to remote sensing, about the key physical processes operating in the atmospheric and magnetospheric regions where they originate. This paper reviews the development of our current understanding of auroral emissions from Jupiter, Saturn, Uranus, and Neptune, as revealed through multispectral observations and supplemented by plasma measurements.

162 citations


Cited by
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Journal ArticleDOI
23 Jan 1987-Science
TL;DR: A better understanding of past atmospheric evolution is important to understanding the evolution of life and to predicting whether Earth-like planets might exist elsewhere in the galaxy.
Abstract: Ideas about atmospheric composition and climate on the early Earth have evolved considerably over the last 30 years, but many uncertainties still remain. It is generally agreed that the atmosphere contained little or no free oxygen initially and that oxygen concentrations increased markedly near 2.0 billion years ago, but the precise timing of and reasons for its rise remain unexplained. Likewise, it is usually conceded that the atmospheric greenhouse effect must have been higher in the past to offset reduced solar luminosity, but the levels of atmospheric carbon dioxide and other greenhouse gases required remain speculative. A better understanding of past atmospheric evolution is important to understanding the evolution of life and to predicting whether Earth-like planets might exist elsewhere in the galaxy.

1,205 citations

Journal ArticleDOI
09 Jan 1992-Nature
TL;DR: Estimates of these sources for plausible end-member oxidation states of the early terrestrial atmosphere suggest that the heavy bombardment before 3.5 Gyr ago either produced or delivered quantities of organics comparable to those produced by other energy sources.
Abstract: The contribution of organic-rich comets, carbonaceous asteroids, and interplanetary dust particles and of impact shock-synthesized organics in the atmosphere to the origin of life on earth is studied and quantitatively compared with the principal non-heavy-bombardment sources of prebiotic organics. The results suggest that heavy bombardment before 3.5 Gyr ago either produced or delivered quantities of organics comparable to those produced by other energy sources.

1,127 citations