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November 2014 HAD Meeting Abstracts

All sessions and meetings in the JW Marriott Tucson Starr Pass Resort & Spa.

HAD I: History of Planetary Astronomy (Joint with DPS)

Session #106: Monday, 10 Nov 2014, 10:30–11:30 a.m. Tucson Ballroom G
Session Chair: Jay M. Pasachoff, Williams College.

10:30 1. Origins of the Lunar and Planetary Laboratory, University of Arizona
Dale P. Cruikshank, NASA's Ames Research Center & William K. Hartmann, Planetary Science Institute.
The roots of the Lunar and Planetary Laboratory (LPL) extend deep into the rich fabric of G. P. Kuiper's view of the Earth as a planet and planetary systems as expected companions to most stars, as well as the post-war emergent technology of infrared detectors suitable for astronomy. These concepts and events began with Kuiper’s theoretical work at Yerkes Observatory on the origin of the Solar System, his discovery of two planetary satellites and observational work with his near-infrared spectrometer on the then-new McDonald 82-inch telescope in the mid- to late-1940s. A grant for the production of a photographic atlas of the Moon in the mid-1950s enabled him to assemble the best existing images of the Moon and acquire new photographs. This brought E. A. Whitaker and D. W. G. Arthur to Yerkes. Others who joined in the lunar work were geologist Carl S. Huzzen and grad student E. P. Moore, as well as undergrad summer students A. B. Binder and D. P. Cruikshank (both in 1958). The Atlas was published in 1959, and work began on an orthographic lunar atlas. Kuiper’s view of planetary science as an interdisciplinary enterprise encompassing astronomy, geology, and atmospheric physics inspired his vision of a research institution and an academic curriculum tuned to the combination of all the scientific disciplines embraced in a comprehensive study of the planets. Arrangements were made with the University of Arizona (UA) to establish LPL in affiliation with the widely recognized Inst. of Atmospheric Physics. Kuiper moved to the UA in late 1960, taking the lunar experts, graduate student T. C. Owen (planetary atmospheres), and associate B. M. Middlehurst along. G. van Biesbroeck also joined the migration to Tucson; Binder and Cruikshank followed along as new grad students. Astronomy grad student W. K. Hartmann came into the academic program at UA and the research group at LPL in 1961. Senior faculty affiliating with LPL in the earliest years were T. Gehrels, A. B. Meinel, H. L. Johnson, and F. J. Low, each with their own grad students and associates. Work began on IR spectroscopy and a rectified lunar atlas. Kuiper and Johnson started the search for future observatory sites in N. America and Hawaii.

10:40 2. Planetary Radio Astronomy: The 60 Years from Burke and Franklin to ALMA
Paul G. Steffes, Georgia Institute of Technology.
For nearly 60 years, radio astronomy has played a major role in the characterization and monitoring of thermal structure, composition, and temporal changes of the planets and small bodies in our solar system. At this, the 60th anniversary of the initial detection of radio emission by a planet, the role radio astronomy has played in the early characterization of solar system objects, in raising basic scientific questions and motivating planetary exploration missions, and in providing insight into the structure and temporal variations of planets is explored. The evolution of the instrumentation capabilities from crude total-power, or bolometric measurements averaged over an entire planetary disk to today's instrumentation providing radio images of planets and comets with high spectral resolution is also discussed. Major developments such as precise total-power calibration, ultra-large apertures, microwave and millimeter-wave array technology, and supporting laboratory spectroscopy have played major roles in enhancing the effectiveness of radio astronomical observations. The newest generation instruments such as the upgraded Jansky Very Large Array (VLA) and the Altacama Large Millimeter Array (ALMA) now usher in a whole new level of capability in observation of solar system objects.

10:50 3. History of the Terminal Cataclysm Concept: A Cataclysm That Never Happened?
William K. Hartmann, Planetary Science Institute.
The "terminal cataclysm" (or "late heavy bombardment") concept of the last 40 years exhibits curious epistemology, with changing definitions and inconsistent evidence. Pre-Apollo evidence showed that the impact rate prior to ~3.5 Ga ago averaged ~150x the post-mare rate [1]. In 1973-4, Tera et al. [2,3] introduced the term “terminal cataclysm,” widespread metamorphism ~3.9 Ga ago, possibly caused by the Imbrium impact [3, p.15], or more likely by “formation of several major basins [in a] short time interval (less than 0.2AE)” [3, p.18]. In 1990, Ryder [4] reported a strong spike in ages for Apollo impact melt rocks ~3.8-4.0 Ga ago, and proposed this as proof that a Moon-wide cataclysmic bombardment occurred at that time, with no earlier cratering. Three inconsistencies soon appeared. (1) In 2002, Cohen et al. [5, also 2002 & 2005] dated lunar meteorite clasts (aiming at non-Apollo lunar regions) and found no spike or anomaly at 3.9 Ga. (Yet they inferred “support for the lunar cataclysm hypothesis.”) (2) The Nice model in early 2000s predicted many planetesimals scattered from the outer to the inner Solar System [6], with a plausible (unconstrained) date of 3.9 Ga - but asteroidal meteorite impact melt clasts (like lunar meteorites) show no spike at 3.9. (3) Meanwhile, reports of pre-4.0 impact melts have increased among upland breccia clasts. Nice and Grand Tack modelers have introduced “sawteeth” spikes before 4.0 and gradual declines after 3.8 (both had been proposed earlier), thus softening the “cataclysm” spike. A 2014 model by Marchi, Bottke, Morbidelli, Kring, et al. [7] illustrates a curve of impact flux vs. time, 4.4 to 3.5 Ga, showing no spike at 3.9 Ga - signaling a possible demise of the terminal cataclysm hypothesis. [1] Hartmann W.K. 1966. Icarus 5, 406-418. [2] Tera F. et al. 1973. LPSC abstract, p. 723. [3] Tera F. et al. 1974. EPSK 22, 1-21. [4] Ryder G. 1990. EOS 71, 313. [5] Cohen B., Swindle T., Kring D. 2000. Science 290, 1754-1756. [6] Morbidelli A., Bottke W. 2006. 1st Int’l Conf. on Impact Cratering in the Solar System (Noordwijk: ESTEC), abstract [7] Marchi S. et al. 2014. Nature 511, 578–582.

11:00 4. Discovery of a Previously Unrecognised Allusion to the Aurora Borealis in Paradise Lost, and Implications for Edmund Halley Scholarship
Clifford J. Cunningham, University of Southern Queensland.
This research reveals that John Milton employed an allusion to the aurora borealis in the epic poem Paradise Lost which has not been recognised in more than three centuries of scholarly analysis. It further disproves the long-held belief, made popular by the astronomer Edmund Halley, that no notable aurora was visible in England in the seventeenth century. A study of the personal Latin diary of the Elizabethan historian William Camden shows that the famous aurora of 1621 was visible in England. While Pierre Gassendi has been credited with creation of the term 'aurora borealis' based on his report of the 1621 aurora, this study reaffirms a neglected analysis from 1986 that established the term originated with Galileo in 1619.

11:10 5. Christiaan Huygens: Sailing and Flying on Other Worlds
Ralph Lorenz, Johns Hopkins University.
In Christiaan Huygens's posthumous book, The Celestial Worlds Discover'd (1698) he lays out an optimistic vision of a universe of various worlds, some populated by beings like ourselves, and even with a few who might be scientists wondering about the same questions. He offers, in essence, a truly modern perspective on planetary physics and astrobiology. He notes that other worlds may have fluids forming clouds and rain, but that these fluids might be different from water, since for example Jupiter and Saturn are far from the sun and this 'water of ours' would be 'liable to frost.' He even speculates that other atmospheres might be thicker than ours, which would be favorable for the locomotion of the 'volatile animals.' Rather germane to present studies of Titan's seas and giant planet interiors, he even wonders if there might be layers of fluids of different densities : "There may also be many forts of Fluids ranged over one another in Rows as it were. The Sea perhaps may have such a fluid lying on it, which tho’ ten times lighter than Water, may be a hundred Time heavier than Air". Huygens considered that mariners on other worlds might use the same pulleys and anchors (noting essentially the universality of function of such devices) yet that other planets might have advantages or disadvantages for any given approach. Indeed, he rues how easy navigation must be on Jupiter and Saturn, having the benefit of so many moons from which Longitude could be determined (a vexing challenge of his day). He even notes that other worlds might have magnetic fields, allowing their sailors to use the compass. As post-Cassini exploration of Titan contemplates a number of vehicle types, from hot air balloons to sailboats which can exploit the thick atmosphere and low gravity of that environment, it is fitting to recall the perspective of Titan's discoverer on other worlds as being similar, but different. The same laws of physics and logic of design apply, but with different environmental parameters and working materials.

11:20 6. Recreating Galileo's 1609 Discovery of Lunar Mountains
Jay M. Pasachoff, Williams College and California Institute of Technology; Paul S. Needham, Princeton University; Ernest T. Wright, NASA's Goddard Space Flight Center; & Owen Gingerich, Harvard-Smithsonian Center for Astrophysics.
The question of exactly which lunar features persuaded Galileo that there were mountains on the moon has not yet been definitively answered; Galileo was famously more interested in the concepts rather than the topographic mapping in his drawings and the eventual engravings. Since the pioneering work of Ewen Whitaker on trying to identify which specific lunar-terminator features were those that Galileo identified as mountains on the moon in his 1609 observations reported in his Sidereus Nuncius (Venice, 1610), and since the important work on the sequence of Galileo's observations by Owen Gingerich (see "The Mystery of the Missing 2" in Galilaeana IX, 2010, in which he concludes that "the Florentine bifolium sheet [with Galileo's watercolor images] is Galileo's source for the reworked lunar diagrams in Sidereus Nuncius"), there have been advances in lunar topographical measurements that should advance the discussion. In particular, one of us (E.T.W.) at the Scientific Visualization Studio of NASA's Goddard Space Flight Center has used laser-topography from NASA's Lunar Reconnaissance Orbiter to recreate what Galileo would have seen over a sequence of dates in late November and early December 1609, and provided animations both at native resolution and at the degraded resolution that Galileo would have observed with his telescope. The Japanese Kaguya spacecraft also provides modern laser-mapped topographical maps.

11:30 Desert Moon.
A documentary film by Jason Davis. Presented with support from the Division of Planetary Sciences.

12:05 End of session