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Articles 1 - 8 of 8
Full-Text Articles in Physics
The Meaning Of Dark, Light And Shadows: Inferences In Art, Materiality And Cultural Practices, Frank Prendergast
The Meaning Of Dark, Light And Shadows: Inferences In Art, Materiality And Cultural Practices, Frank Prendergast
Book/Book Chapter
Our visual awareness relies on light acting on the eye to perceive materiality and colour. Medieval thought wrestled to articulate and comprehend its nature. The notebooks of Leonardo Da Vinci, for example, included his descriptions to define light and make comparisons so as to differentiate between light and shadow. His focus was on the illumination of surfaces from the perspective of a painter, seeing shadows as ‘the diminution of light by the intervention of an opaque body’ and ‘the counterpart of luminous rays’. In his mind, a shadow ‘stood between light and darkness’, with darkness being ‘the absence of light’. …
Design And Construction Of A Computer Controlled Astronomical Spectropolarimeter, Jacob Marchio
Design And Construction Of A Computer Controlled Astronomical Spectropolarimeter, Jacob Marchio
Honors College
A theoretical description of a simple optical train, modulated signal based spectropolarimeter is discussed. The design includes, after the telescope optical tube (in this case, a 9.25” Schmidt Cassegrain), a rotating quarter waveplate (compensator), a fixed linear polarizer (analyzer), and transmission grating of 100l/mm, with a ZWO ASI290mm astronomical camera. The practical constraints on implementing such an instrument are discussed, and the construction of the spectropolarimeter is detailed, including the necessary optics, optomechanics, and electromechanics. The rotation and recording of the rotating compensator is facilitated by a motorized connection with proportional feedback control, and the uncertainty in measuring the angle …
Analysis Of Magnetization Directions Of Lunar Swirls, Lillie Cole
Analysis Of Magnetization Directions Of Lunar Swirls, Lillie Cole
Lewis Honors College Capstone Collection
Lunar Swirls are high albedo markings on the Moon that exist in the regions of some crustal magnetic anomalies. The precise mechanism responsible for the swirl features is unknown but a prevailing theory is solar wind standoff, where the magnetic field from subsurface magnetized sources protects the lunar surface from solar wind ions, leading to their lesser maturation and brighter appearance. If this theory is correct, the magnetic field of the anomalies should heavily influence the appearance of the swirl. To better understand the cause of swirls, the magnetization direction of the source creating the field is analyzed. This study …
The Undeniable Attraction Of Lunar Swirls, Dany Waller
The Undeniable Attraction Of Lunar Swirls, Dany Waller
Posters-at-the-Capitol Presentations
Lunar swirls are complex patterns on the Moon with distinct brightness signatures and magnetic characteristics. Current research has suggested that the formation of lunar swirls relies on local magnetic fields to shield impinging solar wind, based on a shift in electromagnetic wavelength peaks related to solar radiation and space weathering. Our research combined recent models and methods to characterize these anomalies at the surface of the Moon, exploring the effects of field strength and position. We have produced a high resolution map of a famous swirl named Reiner Gamma using magnetic dipole modeling. These maps and models are considered when …
The First Cosmic Ray Albedo Proton Map Of The Moon, Jody K. Wilson, Harlan E. Spence, Justin Kasper, Michael Golightly, J. B. Blake, J. E. Mazur, L. W. Townsend, A. W. Case, M. D. Looper, C. Zeitlin, Nathan A. Schwadron
The First Cosmic Ray Albedo Proton Map Of The Moon, Jody K. Wilson, Harlan E. Spence, Justin Kasper, Michael Golightly, J. B. Blake, J. E. Mazur, L. W. Townsend, A. W. Case, M. D. Looper, C. Zeitlin, Nathan A. Schwadron
Physics & Astronomy
[1] Neutrons emitted from the Moon are produced by the impact of galactic cosmic rays (GCRs) within the regolith. GCRs are high-energy particles capable of smashing atomic nuclei in the lunar regolith and producing a shower of energetic protons, neutrons and other subatomic particles. Secondary particles that are ejected out of the regolith become “albedo” particles. The neutron albedo has been used to study the hydrogen content of the lunar regolith, which motivates our study of albedo protons. In principle, the albedo protons should vary as a function of the input GCR source and possibly as a result of surface …
New Measurements Of Total Ionizing Dose In The Lunar Environment, J. E. Mazur, W. R. Crain, M. D. Looper, D. J. Mabry, J. B. Blake, A. W. Case, M. J. Golightly, J. C. Kasper, Harlan E. Spence
New Measurements Of Total Ionizing Dose In The Lunar Environment, J. E. Mazur, W. R. Crain, M. D. Looper, D. J. Mabry, J. B. Blake, A. W. Case, M. J. Golightly, J. C. Kasper, Harlan E. Spence
Physics & Astronomy
[1] We report new measurements of solar minimum ionizing radiation dose at the Moon onboard the Lunar Reconnaissance Orbiter (LRO) from June 2009 through May 2010. The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on LRO houses a compact and highly precise microdosimeter whose design allows measurements of dose rates below 1 micro-Rad per second in silicon achieved with minimal resources (20 g, ∼250 milliwatts, and ∼3 bits/second). We envision the use of such a small yet accurate dosimeter in many future spaceflight applications where volume, mass, and power are highly constrained. As this was the first …
Gcr Access To The Moon As Measured By The Crater Instrument On Lro, A. W. Case, Harlan E. Spence, M. J. Golightly, J. C. Kasper, J. B. Blake, J. E. Mazur, L. W. Townsend, C. J. Zeitlin
Gcr Access To The Moon As Measured By The Crater Instrument On Lro, A. W. Case, Harlan E. Spence, M. J. Golightly, J. C. Kasper, J. B. Blake, J. E. Mazur, L. W. Townsend, C. J. Zeitlin
Physics & Astronomy
[1] Recent modeling efforts have yielded varying and conflicting results regarding the possibility that Earth's magnetosphere is able to shield energetic particles of >10 MeV at lunar distances. This population of particles consists of galactic cosmic rays as well as energetic particles that are accelerated by solar flares and coronal mass ejections. The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) onboard the Lunar Reconnaissance Orbiter is in orbit about the Moon and is thus able to directly test these modeling results. Over the course of a month, CRaTER samples the upstream solar wind as well as various regions …
Double-Glazing Interferometry, Vincent Toal, Emilia Mihaylova
Double-Glazing Interferometry, Vincent Toal, Emilia Mihaylova
Articles
This note describes how white light interference fringes can be seen by observing the Moon through a double-glazed window. White light interferometric fringes are normally observed only in a well-aligned interferometer whose optical path difference is less than the coherence length of the light source, which is approximately one micrometer for white light. Obtaining such fringes in a Michelson interferometer is not a trivial task.1 The interferometer is typically illuminated with a monochromatic source and the path length difference adjusted with a wedge angle between the interferometer mirrors so that five or six vertical fringes are visible, indicating nearly equal …