Atmospheric Composition, Chemistry, and Clouds

Venus’ atmosphere has a rich chemistry involving interactions among sulfur, chlorine, nitrogen, hydrogen, and oxygen radicals. The chemical regimes in the atmosphere range from ion-neutral reactions in the ionosphere to photochemistry in the middle atmosphere to thermal equilibrium chemistry and surface-atmosphere reactions in the lower atmosphere. This variety makes Venus an important planet to understand within the context of terrestrial-like planets, both in our own solar system and outside it. The primary chemical cycles are believed known but surprisingly few details about these cycles have been fully verified by concurrence among observations, experiments, and modeling. Good models have been developed that account for many properties of the cloud layers, but the size distribution, shape, and composition of the majority of the aerosol mass are still open issues. This chapter reviews the state of knowledge prior to the Venus Express mission for the composition, chemistry, and clouds of the neutral atmosphere on Venus. Observations by instruments on Venus Express, in combination with ground-based observations, laboratory experiments, and numerical modeling, should answer some of the major open questions regarding the composition, chemistry, and clouds of Venus’ atmosphere

Future Venus Probe Missions

Probes are essential to understanding Venus Direct implications for Earth's formation and history, origin of life, extra solar planets Range of desired capability includes: a) Multiprobes; b) Descenders; c) Landers; d) Balloons; and e) Long-lived landers

Meter-Sized Moonlet Population in Saturn\u27s C Ring and Cassini Division

Stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph reveal the presence of transparent holes a few meters to a few tens of meters in radial extent in otherwise optically thick regions of the C ring and the Cassini Division. We attribute the holes to gravitational disturbances generated by a population of similar to 10 m boulders in the rings that is intermediate in size between the background ring particle size distribution and the previously observed similar to 100 m propeller moonlets in the A ring. The size distribution of these boulders is described by a shallower power-law than the one that describes the ring particle size distribution. The number and size distribution of these boulders could be explained by limited accretion processes deep within Saturn\u27s Roche zone

Assessing Community Foundation Needs and Envisioning the Future

Community foundations have several attributes that, taken together, distinguish them from many of their philanthropic brethren, including a local orientation, relationships with many living donors, and a public charity tax status. This affects everything from their approach to solving problems to their business model. Because of this, community foundations have sought out support services that are designed for their particular needs. The infrastructure of organizations serving community foundations has evolved, and there has been confusion among community foundations over where to get their needs met and some frustration over the perceived fragmentation of services.In response to these concerns and to create some clarity, CFLeads and CF Insights, both of which exclusively serve community foundations, decided to map out the current support services and lead a discussion exploring a vision for the future. The findings from a survey of a dozen large community foundations and a one-day symposium are summarized here. Hopefully the results of this partnership provide a better understanding of the ecosystem of organizations serving community foundations and some initial thinking on how to meet needs in the future