A Predator-Prey Model For Moon-Triggered Clumping In Saturn\u27S Rings

UVIS occultation data show clumping in Saturn\u27s F ring and at the B ring outer edge, indicating aggregation and disaggregation at these locations that are perturbed by Prometheus and by Mimas. The inferred timescales range from hours to months. Occultation profiles of the edge show wide variability, indicating perturbations by local mass aggregations. Structure near the B ring edge is seen in power spectral analysis at scales 200-2000. m. Similar structure is also seen at the strongest density waves, with significance increasing with resonance strength. For the B ring outer edge, the strongest structure is seen at longitudes 90° and 270° relative to Mimas. This indicates a direct relation between the moon and the ring clumping. We propose that the collective behavior of the ring particles resembles a predator-prey system: the mean aggregate size is the prey, which feeds the velocity dispersion; conversely, increasing dispersion breaks up the aggregates. Moons may trigger clumping by streamline crowding, which reduces the relative velocity, leading to more aggregation and more clumping. Disaggregation may follow from disruptive collisions or tidal shedding as the clumps stir the relative velocity. For realistic values of the parameters this yields a limit cycle behavior, as for the ecology of foxes and hares or the boom-bust economic cycle. Solving for the long-term behavior of this forced system gives a periodic response at the perturbing frequency, with a phase lag roughly consistent with the UVIS occultation measurements. We conclude that the agitation by the moons in the F ring and at the B ring outer edge drives aggregation and disaggregation in the forcing frame. This agitation of the ring material may also allow fortuitous formation of solid objects from the temporary clumps, via stochastic processes like compaction, adhesion, sintering or reorganization that drives the denser parts of the aggregate to the center or ejects the lighter elements. Any of these more persistent objects would then orbit at the Kepler rate. We would also expect the formation of clumps and some more permanent objects at the other perturbed regions in the rings... including satellite resonances, shepherded ring edges, and near embedded objects like Pan and Daphnis (where the aggregation/disaggregation cycles are forced similar to Prometheus forcing of the F ring). © 2011 Elsevier Inc

NASA Science4Girls: Engaging Girls in STEM at Their Local Library

The NASA Science Mission Directorate (SMD) Science Education and Public Outreach Forums coordinate the participation of SMD education and public outreach (EPO) programs inWomen’s HistoryMonth through the NASA Science4Girls and Their Families initiative. The initiative partners NASA science education programs with public libraries to provide NASA-themed hands-on education activities for girls and their families. The initiative has expanded from the successful 2012 Astro4Girls pilot to engage girls in all four NASA science discipline areas, which broadens the impact of the pilot by enabling audiences to experience the full range of NASA science topics and the different career skills each requires. The events focus on engaging underserved and underrepresented audiences in Science, Technology, Engineering, and Mathematics (STEM) via use of research-based best practices, collaborations with libraries, partnerships with local and national organizations, and remote engagement of audiences

NASA’s Coordinated Efforts to Enhance STEM Education: Bringing NASA Science into the Library

Libraries are community-centered, free-access venues serving learners of all ages and backgrounds. Libraries also recognize the importance of science literacy and strive to include science in their programming portfolio. Scientists and educators can partner with local libraries to advance mutual goals of connecting the public to Earth and Space Science. In this interactive Special Interest Group (SIG) discussion, representatives from the NASA Science Mission Directorate (SMD) Education and Public Outreach (EPO) community’s library collaborations discussed the opportunities for partnership with public and school libraries; explored the resources, events, and programs available through libraries; explored NASA science programming and professional development opportunities available for librarians; and strategized about the types of support that librarians require to plan and implement programs that use NASA data and resources. We also shared successes, lessons learned, and future opportunities for incorporating NASA science programming into library settings

Moonlets And Clumps In Saturn\u27S F Ring

Cassini UVIS star occultations by the F ring detect 13 events ranging from 27 m to 9 km in width. We interpret these structures as likely temporary aggregations of multiple smaller objects, which result from the balance between fragmentation and accretion processes. One of these features was simultaneously observed by VIMS. There is evidence that this feature is elongated in azimuth. Some features show sharp edges. At least one F ring object is opaque and may be a moonlet. This possible moonlet provides evidence for larger objects embedded in Saturn\u27s F ring, which were predicted as the sources of the F ring material by Cuzzi and Burns [Cuzzi, J.N., Burns, J.A., 1988. Icarus 74, 284-324], and as an outcome of tidally modified accretion by Barbara and Esposito [Barbara, J.M., Esposito, L.W., 2002. Icarus 160, 161-171]. We see too few events to confirm the bi-modal distribution which Barbara and Esposito [Barbara, J.M., Esposito, L.W., 2002. Icarus 160, 161-171] predict. These F ring structures and other youthful features detected by Cassini may result from ongoing destruction of small parent bodies in the rings and subsequent aggregation of the fragments. If so, the temporary aggregates are 10 times more abundant than the solid objects. If recycling by re-accretion is significant, the rings could be quite ancient, and likely to persist far into the future. © 2007 Elsevier Inc. All rights reserved

Introducing Recent NASA Discoveries into the Astro 101 Classroom with Modular Slide Sets

This paper summarizes the special interest group discussion about slides sets for use by Astronomy 101 instructors. The NASA Science Mission Directorate Astrophysics Education and Public Outreach Forum is coordinating the development of a pilot series of slide sets to help Astronomy 101 instructors incorporate new discoveries in their classrooms. The “Astro 101 slide sets” are presentations of 5–7 slides on a new development or discovery from a NASA Astrophysics mission relevant to topics in introductory astronomy courses. We intend for these slide sets to help Astronomy 101 instructors include new developments (discoveries not yet in their textbooks) into the broader context of the course. With their modular design and non-technical language, the slide sets may also serve audiences beyond Astronomy 101 instruction and are adaptable to different needs. An example on exoplanets was highlighted in this session. In this paper, we outline the community feedback, which falls into the broad categories of content, format, uses, relevant topics, and future adaptations

NASA Astrophysics EPO Community: Enhancing STEM Instruction

The NASA Science Mission Directorate (SMD) Astrophysics Education and Public Outreach (EPO) community and Forum work together to capitalize on the cutting-edge discoveries of NASA Astrophysics missions to enhance Science, Technology, Engineering, and Math (STEM) instruction. In 2010, the Astrophysics EPO community identified online professional development for classroom educators and multiwavelength resources as a common interest and priority for collaborative efforts. The result is NASA’s Multiwavelength Universe, a 2–3 week online professional development experience for classroom educators. The course uses a mix of synchronous sessions (liveWebEx teleconferences) and asynchronous activities (readings and activities that educators complete on their own on the Moodle, and moderated by course facilitators). The NASA SMD Astrophysics EPO community has proven expertise in providing both professional development and resources to K–12 Educators. These mission and grant-based EPO programs are uniquely poised to foster collaboration between scientists with content expertise and educators with pedagogy expertise. We present examples of how the NASA Astrophysics EPO community and Forum engage the K–12 education community in these ways, including associated metrics and evaluation findings

NASA Astrophysics EPO Community: Increasing and Sustaining Youth and Public Engagement in STEM

The NASA Science Mission Directorate (SMD) Astrophysics Education and Public Outreach (EPO) community and Forum work together to capitalize on the cutting-edge discoveries of NASA Astrophysics missions to enable youth to engage directly in doing Science, Technology, Engineering, and Mathematics (STEM) inside and outside of school. The NASA SMD Astrophysics EPO community has proven expertise in providing student opportunities that reinforce research skills; exhibits, multimedia shows, and visualizations that inspire and engage; professional development for informal educators; and partnerships that provide local, regional, and national reach. These mission- and grant-based EPO programs are uniquely poised to foster collaboration between scientists with content expertise and educators with pedagogy expertise. We present examples of how the NASA Astrophysics EPO community and Forum support youth and public engagement in STEM in these ways, including associated metrics and evaluation findings

NASA Astrophysics EPO Community: Enhancing STEM Experience of Undergraduates

The NASA Science Mission Directorate (SMD) Astrophysics Education and Public Outreach (EPO) community and Forum work together to capitalize on the cutting-edge discoveries of NASA Astrophysics missions to enhance the Science, Technology, Engineering, and Math (STEM) experience of undergraduates. The NASA SMD Astrophysics EPO community has proven expertise in providing both professional development and resources to faculty at two- and four-year institutions and in offering internships and student collaboration opportunities. These mission- and grant-based EPO programs are uniquely poised to foster collaboration between scientists with content expertise and educators with pedagogy expertise. We present examples of how the NASA Astrophysics EPO community and Forum engage the higher education community in these ways, including associated metrics and evaluation findings

NASA Astrophysics EPO Community: Serving Groups Historically Underrepresented in STEM Fields

Four Science Education and Public Outreach Forums support and coordinate the NASA Science Mission Directorate (SMD) education and public outreach (EPO) community. The mission- and grant-based EPO programs of this EPO community are uniquely poised to foster collaboration between scientists with content expertise and educators with pedagogy expertise. The Forums engage underserved audiences through coordinated efforts such as NASAScience4Girls and Their Families, which partners NASA science education programs with public libraries to provide NASA-themed, hands-on education activities for girls and their families, along with training for librarians. We present examples of how the NASA EPO community and Forums serve groups historically underrepresented in STEM fields via the NASAScience4Girls and Their Families initiative, including associated metrics and evaluation findings