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Articles 61 - 73 of 73

Full-Text Articles in The Sun and the Solar System

Experimental Simulations Of Dark Slope Streaks On Mars, Kelly Howe May 2012

Experimental Simulations Of Dark Slope Streaks On Mars, Kelly Howe

Graduate Theses and Dissertations

Martian slope streaks were first observed in Viking images but their formation still remains ambiguous. Martian slope streaks are currently occurring geological phenomenon on Mars, which requires any formation theory to be in agreement with Mar's current temperature and pressure conditions. Planar morphology of martian slope streaks suggest a potential fluvial formation, but current conditions on Mars are not conducive to water remaining liquid long enough to erode the surface. Debris flows, fluid stains and dry dust avalanches have all been previously cited as a potential formation mechanism for martian slope streaks. Recent experimental simulations indicate that a fluvial source …


New Methods For The Discovery And Characterization Of Lunar Lava Tubes Using Lunar Reconnaissance Orbiter Data, Jonathan Arthur Meyer Jan 2012

New Methods For The Discovery And Characterization Of Lunar Lava Tubes Using Lunar Reconnaissance Orbiter Data, Jonathan Arthur Meyer

Open Access Theses & Dissertations

Lava tubes have the potential to serve as a sustainable solution to long-term lunar habitation by providing protection from radiation and micrometeorite bombardment while potentially providing resources in the form of trapped water ice. They also pose compelling science targets in their own right. While the potential benefits of utilizing lunar lava tubes is clear, their discovery is less straightforward. Formation processes for lava tubes do not always result in a surface expression, making their discovery using remotely sensed imagery difficult. Furthermore, there is the potential for lava tubes to be covered by secondary lava flows, impact ejecta, or other …


Phreatomagmatic Activity On The Moon: Possibility Of Pseudocraters At Mare Frigoris, Jose Humberto Garcia Jan 2012

Phreatomagmatic Activity On The Moon: Possibility Of Pseudocraters At Mare Frigoris, Jose Humberto Garcia

Open Access Theses & Dissertations

The discovery of water on the Moon raises the possibility that lava-water, or phreatomagmatic, interactions have occurred on the lunar surface in the past. Such interactions may have formed pseudocraters, crater-like landforms that result from steam explosions that occur when lava flows come in contact with surface or near-surface water or ice. We present a study of Mare Frigoris, a volcanic plain just north of the Mare Imbrium impact basin on the Moon. Clusters of irregular, circular features on the basaltic lava flows in this area resemble pseudocrater fields in Iceland, and they are located in a region with inferred …


Numerical Modeling Of Tectonics And Fault Activity Of Icy Satellites, John Olgin Jan 2012

Numerical Modeling Of Tectonics And Fault Activity Of Icy Satellites, John Olgin

Open Access Theses & Dissertations

Enceladus, one of the satellites of Saturn, exhibits evidence of recent fault activity, which may be due to gravitational fluctuations, or tidal stresses, generated by its orbit around Saturn. Recent Cassini spacecraft observations of Enceladus reveal water-ice plume activity at the south polar region, originating from locations that correlate with four geologically young, linear fracture-like features, named the "tiger stripes". It is the goal of this investigation to determine the ideal geophysical and geological factors (e.g., fault depths, frictional coefficients, ice layer thickness, ocean layer thickness, tidal stress sources) that support fault activity on Enceladus. The core of this work …


Characterization Of Thrust Faults On The Moon Using Fault Dynamics And 3d Visualizations, Jaclyn Danielle Clark Jan 2012

Characterization Of Thrust Faults On The Moon Using Fault Dynamics And 3d Visualizations, Jaclyn Danielle Clark

Open Access Theses & Dissertations

Many small, lobate scarps, interpreted to be the surface traces of thrust faults, have been found all over Earth's moon by previous researchers. Fault dynamical calculations, assuming an initially completely molten Moon, have shown that these scarps can form due to compressional stresses that accumulate over time as the result of large-scale contraction of the Moon as it cooled. With high-resolution images from the Lunar Reconnaissance Orbiter Camera (LROC), previously undetected lobate scarps can be found globally and viewed at high resolution. By investigating these fault scarps, we can determine better constraints on the amount of crustal shortening and improve …


Book Review: Stars Above, Earth Below: A Guide To Astronomy In The National Parks, T. D. Oswalt Nov 2010

Book Review: Stars Above, Earth Below: A Guide To Astronomy In The National Parks, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Stars Above, Earth Below : a Guide to Astronomy in the National Parks by Tyler Nordgren. Springer/Praxis, 2010 444p, 9781441916488 $29.95.


A Two-Dimensional, Linear–Elastic Model To Explain Radial Extensional Fractures, Pantheon Fossae, Caloris Basin, Mercury, Brianne Mcdonough Jan 2010

A Two-Dimensional, Linear–Elastic Model To Explain Radial Extensional Fractures, Pantheon Fossae, Caloris Basin, Mercury, Brianne Mcdonough

Undergraduate Review

In this study, two-dimensional linear elasticity theory is used to model the lithospheric stress field that produces radial extensional fractures observed at Pantheon Fossae in the Caloris Basin of Mercury. These fractures were imaged by the MESSENGER mission flyby of Mercury on January 14, 2008 and show radial fractures extending outward from a 40-kilometer impact crater named Apollodorus. Recent studies have proposed several different mechanisms to explain these fractures, including magmatic processes, central basin uplift, and stresses produced by the formation of the impact crater itself.


Martian Life Detection With Xylose Enantiomers, Arturo White, Gaosun Zhang, Henry J. Sun Aug 2009

Martian Life Detection With Xylose Enantiomers, Arturo White, Gaosun Zhang, Henry J. Sun

Undergraduate Research Opportunities Program (UROP)

Ability of Martian soil to degrade carbohydrates, shown by the Viking mission, has two interpretations. One possibility is that the soil harbors living microorganisms. Alternatively, the soil is sterile but chemically oxidizing, i.e. it is laden with photochemical oxidants. It was shown by REU research last summer that these two possibilities can be distinguished by the use of glucose enantiomers. Life is selective: Earth organisms use D-glucose, but ignore Lglucose. This stereo selectivity is absent in chemical reactions. The goal of this project is to test if xylose, a five carbon sugar, is also suitable for chiral life detection. Mixed …


Martian Life Detection With Amino Acid Enantiomers, Ali Jamil, Gaosen Zhang, Henry J. Sun Aug 2009

Martian Life Detection With Amino Acid Enantiomers, Ali Jamil, Gaosen Zhang, Henry J. Sun

Undergraduate Research Opportunities Program (UROP)

The Viking mission showed that Martian soil can degrade a heterotrophic medium to carbon dioxide as if live microorganisms were present. The result is considered inconclusive, however, because abiotic oxidants, such as superoxides, may also exist on Mars and would explain the Viking result. One way to resolve this ambiguity is to repeat the Viking experiment with a isomerically pure medium. The consumption of one isomer, either D or L, would indicate biological activity. Indiscriminate destruction of both isomers would indicate abiotic redox processes. This idea was validated for glucose by REU research last summer (Sun et al. 2009). The …


The Very Basics Of Sustainability - An Alternative Viewpoint (Slides With Audio) (Large File! To Speed Up Download, Right-Click On "Download" Link To Save To Own Pc.), Jim Mcgovern Aug 2009

The Very Basics Of Sustainability - An Alternative Viewpoint (Slides With Audio) (Large File! To Speed Up Download, Right-Click On "Download" Link To Save To Own Pc.), Jim Mcgovern

Other resources

This presentation sets out the very basics of ‘sustainability’, although a definition of sustainability is not attempted. Some of the very basics are the context in which the Earth and humankind exist in space and time, the Earth’s climate, the Earth’s population and humankind’s options and choices. The author advocates keeping an open mind on all available options, including the use of oil, gas, coal, tar sands, carbon capture and sequestration, nuclear power etc., as well as the technologies that are more widely considered ‘green’. The author also argues that, in addressing the challenges that humankind faces, globally concerted effort …


Stereospecificity In Glucose Consumption: A New Approach To Martian Life Detection, Vienna R. Saccomanno, Henry J. Sun Aug 2008

Stereospecificity In Glucose Consumption: A New Approach To Martian Life Detection, Vienna R. Saccomanno, Henry J. Sun

Undergraduate Research Opportunities Program (UROP)

In 1976, the Viking mission made a remarkable discovery: Martian soil was capable of decomposing an organic nutrient broth to carbon dioxide as if it contained live microorganisms. However, a biological interpretation of this finding is in apparent contradiction with the gas chromatograph-mass spectrometer aboard the Viking landers, which showed Martian soil to be devoid of indigenous organics. To reconcile these findings, it has been hypothesized that unknown abiotic oxidants, such as peroxide and superoxide, are present on Mars and that they were responsible for its soil reactivity. The objective of this research is to develop a life detection method …


Ua94/6/2/7 Physiography Notebook, Carl Ellis Jan 1911

Ua94/6/2/7 Physiography Notebook, Carl Ellis

Student/Alumni Personal Papers

Atlas Science Table for Laboratory Notes and Drawings in Physiography notebook used by Carl Ellis for Robert Green's class.


Ua94/6/2/14 Physiography Notebook, Annie Reis Jan 1910

Ua94/6/2/14 Physiography Notebook, Annie Reis

Student/Alumni Personal Papers

Physiography notebook kept by student Annie Reis in 1910. Notebook includes notes and drawings related to physical geography such as solar systems, rivers, faults, weather and glaciers.