Glory revealed in disk-integrated photometry of Venus

Context. Reflected light from a spatially unresolved planet yields unique insight into the overall optical properties of the planet cover. Glories are optical phenomena caused by light that is backscattered within spherical droplets following a narrow distribution of sizes; they are well known on Earth as localised features above liquid clouds. Aims. Here we report the first evidence for a glory in the disk-integrated photometry of Venus and, in turn, of any planet. Methods. We used previously published phase curves of the planet that were reproduced over the full range of phase angles with model predictions based on a realistic description of the Venus atmosphere. We assumed that the optical properties of the planet as a whole can be described by a uniform and stable cloud cover, an assumption that agrees well with observational evidence. Results. We specifically show that the measured phase curves mimic the scattering properties of the Venus upper-cloud micron-sized aerosols, also at the small phase angles at which the glory occurs, and that the glory contrast is consistent with what is expected after multiple scattering of photons. In the optical, the planet appears to be brighter at phase angles of 11-13 deg than at full illumination; it undergoes a maximum dimming of up to 10 percent at phases in between. Conclusions. Glories might potentially indicate spherical droplets and, thus, extant liquid clouds in the atmospheres of exoplanets. A prospective detection will require exquisite photometry at the small planet-star separations of the glory phase angles.Comment: In press. Astronomy & Astrophysics. Letter to the Editor; 201

The swan song: the disappearance of the nucleus of NGC 4051 and the echo of its past glory

BeppoSAX observed the low-luminous Seyfert 1 Galaxy NGC4051 in a ultra-dim X-ray state. The 2-10 keV flux (1.26 x 10^{-12} erg/cm^2/s) was about 20 times fainter than its historical average value, and remained steady along the whole observation (~2.3 days). The observed flat spectrum (\Gamma ~ 0.8) and intense iron line (EW ~600 eV) are best explained assuming that the active nucleus has switched off, leaving only a residual reflection component visible.Comment: 5 pages, Latex, 3 Postscript figures, accepted for publication in MNRA

Titan brighter at twilight than in daylight

Investigating the overall brightness of planets (and moons) provides insight into their envelopes and energy budgets [1, 2, 3, 4]. Titan phase curves (a representation of overall brightness vs. Sun-object-observer phase angle) have been published over a limited range of phase angles and spectral passbands [5, 6]. Such information has been key to the study of the stratification, microphysics and aggregate nature of Titan's atmospheric haze [7, 8], and has complemented the spatially-resolved observations first showing that the haze scatters efficiently in the forward direction [7, 9]. Here we present Cassini Imaging Science Subsystem whole-disk brightness measurements of Titan from ultraviolet to near-infrared wavelengths. The observations reveal that Titan's twilight (loosely defined as the view when the phase angle 150deg) outshines its daylight at various wavelengths. From the match between measurements and models, we show that at even larger phase angles the back-illuminated moon will appear much brighter than when fully illuminated. This behavior is unique to Titan in our solar system, and is caused by its extended atmosphere and the efficient forward scattering of sunlight by its atmospheric haze. We infer a solar energy deposition rate (for a solar constant of 14.9 Wm-2) of (2.84+/-0.11)x10^14 W, consistent to within 1-2 standard deviations with Titan's time-varying thermal emission spanning 2007- 2013 [10, 11]. We propose that a forward scattering signature may also occur at large phase angles in the brightness of exoplanets with extended hazy atmospheres, and that this signature has valuable diagnostic potential for atmospheric characterization.Comment: Pre-print of a manuscript published in Nature Astronomy 1, 0114 (2017) DOI: 10.1038/s41550-017-0114, http://www.nature.com/nastronom

'This New Conquering Empire of Light and Reason:' Edmund Burke, James Gillray, and the Dangers of Enlightenment

This article examines the use of images of “light” and “enlightenment” in Edmund Burke’s Reflections on the Revolution in France and in the controversy that greeted the book, with an emphasis on caricatures of Burke and his book by James Gillray and others. Drawing on Hans Blumenberg’s discussion of the metaphor of “light as truth,” it situates this controversy within the broader usage of images of light and reason in eighteenth-century frontispieces and (drawing on the work of J.G.A. Pocock and Albert O. Hirschman) explores the ways in which Burke’s critique of Richard Price operates with a rhetoric that views Price as part of an enlightenment that was inherently “radical” and, hence, a threat to the “enlightenment” that, in Burke’s view, had already been achieved

University High Highlights 2/19/1958

This is the student newspaper from University High School, the high school that was on the campus of Western Michigan University, then called University High Highlights, in 1958

State Highlights 11/7/1956

This is the student newspaper from Western State High School, the high school that was on the campus of Western Michigan University, then called State Highlights, in 1956

“The Cloud of Unseeing”: Myths Transformed and Pseudo-scientific Interpretations of the Book of Genesis

This paper, delivered at the Tolkien Seminar (Kalamazoo, MI) on May 9, 2018, traces the potential influence of popular late 19th-century Biblical commentaries on the Book of Genesis on Tolkien\u27s post Lord Of the Rings cosmologies, in particular the problem of the creation of the Sun and Moon

Aphasia

Poem sequence relating to colony collapse in bee