In his book Plurality of Worlds, Steven J. Dick (1984) has chronicled the millennia of discourse about other inhabited worlds, based upon deeply held religious or philosophical belief systems. The popularity of the idea of extraterrestrial life has waxed and waned and, at its nadir, put proponents at mortal risk. The several generations of scientists now attending this General Assembly of the International Astronomical Union at the beginning of the 21st century have a marvelous opportunity to shed light on this old question of habitable worlds through observation, experimentation, and interpretation, without recourse to belief systems and without risking their lives (though some may experience rather bumpy career paths). The newly-named and funded, multi-disciplinary field of astrobiology is extremely broad in its scope and is encouraging IAU members to learn and speak the languages of previously disparate disciplines in an attempt to answer the big picture questions: ‘Where did we come from?’, ‘Where are we going?’, and ‘Are we alone?’ These are questions that the general public understand and support, and these are questions that are attracting students of all ages to science and engineering programs. These questions also push the limits of modern instrumentation to explore the cosmos remotely across space and time, as well as to examine samples of interplanetary space returned to the laboratory and samples of distant time teased out of our own Earth.

Within my personal event horizon, the other planetary systems long-predicted by theorists have been uncovered, along with many whose structures were not predicted. The ‘just-so’ conditions requisite for the comfort of astronomers have been understood to be only a very narrow subset of the conditions that nurture extremophilic, microbial life. Thus the potentially habitable real estate beyond Earth has been greatly expanded and within the next few decades it may be possible to detect the biosignatures or technosignatures of inhabitants on distant worlds, should there be any.

The Reynolds Stress Model (RSM) yields the dynamic equations for the second-order moments (e.g., heat fluxes) needed in the equations for the mean variables (e.g., mean temperature). The RSM equations are in general time dependent and non-local. We first discuss the “buoyancy only” case and the tests of the non-local model against a variety of data. We also “plumenize” the model in order to exhibit the up-down flows that characterize convection so as to show that a non-local RSM is fully equipped to account for the “plume aspect” of buoyant flows. Next, we extend the RSM to account for stable and/or unstable stratification and shear, a formalism that is needed to describe the overshooting region contributed by differentail rotation. We conclude by discussing the equation for the dissipation of turbulent kinetic energy which plays a key role in any RSM.

Turbulent convection carries most of the solar luminosity from the stable radiative interior to the visible surface over a substantial fraction of the solar radius. The turbulent motions are highly nonlinear displaying activity on several spatial and temporal scales. The effects of these motions are to redistribute angular momentum, mix light elements, excite gravity waves and power magnetic activity. In this talk, I shall review some of the recent efforts, mostly based on numerical simulations, to model turbulent convection spanning multiple scale heights. I will discuss what we have learnt about the nature of convective transport, and what the relevant timescales are on which convection operates.

The Minimum Orbit Intersection Distance (MOID) between two confocal Keplerian orbits is a useful tool to know if two celestial bodies can collide or undergo a very close approach. We describe some results and open problems on the number of local minimum points of the distance between two points on the two orbits and the position of such points with respect to the mutual nodes. The errors affecting the observations of an asteroid result in uncertainty in its orbit determination and, consequently, uncertainty in the MOID. The latter is always positive and is not regular where it vanishes; this prevents us from considering it as a Gaussian random variable, and from computing its covariance by standard tools. In a recent work we have introduced a regularization of the maps giving the local minimum values of the distance between two orbits. It uses a signed value of the distance, with the sign given to the MOID according to a simple orientation property. The uncertainty of the regularized MOID has been computed for a large database of orbits. In this way we have searched for Virtual PHAs, i.e. asteroids which can belong to the category of PHAs (Potentially Hazardous Asteroids) if the errors in the orbit determination are taken into account. Among the Virtual PHAs we have found objects that are not even NEA, according to their nominal orbit.

We review how the so-called flux-transport solar dynamos work and show that such models calibrate well with solar cycle observations, and simulate well the relative peaks of the past 8 cycles. This success provides a basis for forecasting a strong solar cycle 24. We also show that a previous forecast of the timing of onset of cycle 24 is being verified by recent sunspot area statistics and coronal structures.

The impact on the predicted Teff scale of using the latest MARCS model atmospheres, instead of a fixed atmospheric structure (e.g., the gray T–τ relation) is examined. The former were fitted to stellar interior models at both the photosphere and at τ = 100 to determine the sensitivity of evolutionary tracks and isochrones for [Fe/H] = 0.0 and −2.0 to the chosen fitting point. In the case of solar abundances, the Teff of the giant branch varied by up to 100–150 K, depending on how the outer layers were treated. Much smaller variations were found for metal-poor giants (or main-sequence stars). Interestingly, models for the low solar Z favored by Asplund et al. (Z=0.0125) were unable to reproduce the gap near the turnoff in the C-M diagram of the old open cluster M 67, in contrast to models that assume Z=0.0188.

Any international effort to promote astronomy world wide today must necessarily take into account its cultural and historical component. The past few decades have ushered in an age, which we may call the Age of Cultural Copernicanism. In analogy with the cosmological principle that the universe has no preferred location or direction, Cultural Copernicanism would imply that no cultural or geographical area, or ethnic or social group, can be deemed to constitute a superior entity or a benchmark for judging or evaluating others.

In this framework, astronomy (as well as science in general) is perceived as a multi-stage civilizational cumulus where each stage builds on the knowledge gained in the previous stages and in turn leads to the next. This framework however is a recent development. The 19th century historiography consciously projected modern science as a characteristic product of the Western civilization decoupled from and superior to its antecedents, with the implication that all material and ideological benefits arising from modern science were reserved for the West.

As a reaction to this, the orientalized East has often tended to view modern science as “their” science, distance itself from its intellectual aspects, and seek to defend, protect and reinvent “our” science and the alleged (anti-science) Eastern mode of thought. This defensive mind-set works against the propagation of modern astronomy in most of the non-Western countries. There is thus a need to construct a history of world astronomy that is truly universal and unselfconscious.

Similarly, the planetarium programs, for use the world over, should be culturally sensitive. The IAU can help produce cultural-specific modules. Equipped with this paradigmatic background, we can now address the question of actual means to be adopted for the task at hand. Astronomical activity requires a certain minimum level of industrial activity support. Long-term maintenance of astronomical equipment is not a trivial task. There are any number of examples of an expensive facility falling victim to AIDS: Astronomical Instrument Deficiency Syndrome. The facilities planned in different parts of the world should be commensurate with the absorbing power of the acceptor rather than the level of the gifter.

The Sun's magnetic field is produced throughout the solar interior; it emerges and is dispersed by surface and subsurface flows, and then expands above the surface to dominate the structure of the corona. To resolve the effects of the magnetic field it is necessary to image the interior and measure its rotation and flow systems; track the responses of the magnetic fields to flows in the surface; and to follow the evolution of structures in the corona. Because the Sun is dynamic both high spatial and temporal resolution are essential. Because the Sun's magnetic field effects encompass the entire spherical exterior, the entire surface and outer atmosphere must be mapped. And because the magnetic field is cyclic high-resolution observations must be maintained over multiple cycles.

Microquasars provide new insights into: 1) the physics of relativistic jets from black holes, 2) the connection between accretion and ejection, and 3) the physical mechanisms in the formation of stellar-mass black holes. Furthermore, the studies of microquasars in our Galaxy can provide in the future new insights on: 1) a large fraction of the ultraluminous X-ray sources in nearby galaxies, 2) gamma-ray bursts (GRBs) of long duration in distant galaxies, and 3) the physics in the jets of blazars. If jets in GRBs, microquasars and Active Galactic Nuclei (AGN) are due to a unique universal magnetohydrodynamic mechanism, synergy of the research on these three different classes of cosmic objects will lead to further progress in black hole physics and astrophysics.

In keeping with its co-sponsorship by members of both the “close” and “wide” binary star communities, IAU Symposium 240 has been jointly dedicated to the honor of Czech astronomer Mirek J. Plavec and the memory of U.S. astronomer Charles E. Worley.

We summarize a continuing investigation of turbulence in high-latitude translucent molecular clouds. These low mass (~50–100 M), nearby (~100 pc), non-star forming clouds appear to be condensing out of the atomic cirrus. Unlike star-forming clouds the velocity fields in the clouds must be driven by external processes. Our detailed mapping of the clouds MBM 3,16 and 40 indicates that the dynamics in these clouds result from the combination of shear-flow and thermal instabilities, not shocks. These clouds also show coherent structures, non-Gaussian PDFs but no clear velocity-size relation. Lastly, the energetics of these clouds indicate that radiative loss may terminate the cascade before local heating takes place.

I report on recent measurements of two scaling relations of spheroids in the distant universe, the Fundamental Plane, and the relation between lensing velocity dispersion and stellar velocity dispersion. The joint analysis of the two scaling relations indicates that the most massive (above ~1011.5M⊙) spheroids are consistent with no evolution since z ~ 1 both in terms of star formation and internal structure. Furthermore their total mass density profile is on average well described by an isothermal sphere with no evidence for redshift evolution. At smaller masses the picture appears to be substantially different, as indicated by evidence for substantial recent star formation (as much as 20–40% of stellar mass formed since z ~ 1), and by hints of a reduced dark matter content at smaller masses. A larger sample of lenses extending to velocity dispersions below 200\kms, and to redshifts above >0.5 is needed to verify these trends.

Historically, technological progress with detectors and instrumentation has been essential for advances in any field of observational astronomy, e.g. the advent of CCDs being crucial for high dynamic range imaging and quantitative spectroscopy of galactic PNe, faint object spectrophotometry for the discovery of extragalactic PNe to distances as far as 100 Mpc, etc. The emerging technique of integral field (“3D”) spectroscopy, which is being applied quite successfully to extragalactic astronomy, has unfortunately hardly been used so far for the study of PNe. However, 3D spectroscopy has an enormous potential for various observational problems, ranging from high spatial resolution emission line mapping in different wavelengths simultaneously, over extremely high sensitivity spectroscopy of low surface brightness objects like e.g. PN haloes, to accurate 3D spectrophotometry of extragalactic PNe, and many others. As an attempt to encourage PN researchers to make better use of these new opportunities, the presently existing suite of 3D instruments on 4–8m class telescopes is reviewed, highlighting some examples of successful 3D observations for the study of PNe.

Many similar phenomena occur in astrophysical systems with spatial and mass scales different by many orders of magnitudes. For examples, collimated outflows are produced from the Sun, proto-stellar systems, gamma-ray bursts, neutron star and black hole X-ray binaries, and supermassive black holes; various kinds of flares occur from the Sun, stellar coronae, X-ray binaries and active galactic nuclei; shocks and particle acceleration exist in supernova remnants, gamma-ray bursts, clusters of galaxies, etc. In this report I summarize briefly these phenomena and possible physical mechanisms responsible for them. I emphasize the importance of using the Sun as an astrophysical laboratory in studying these physical processes, especially the roles magnetic fields play in them; it is quite likely that magnetic activities dominate the fundamental physical processes in all of these systems.

As a case study, I show that X-ray lightcurves from solar flares, black hole binaries and gamma-ray bursts exhibit a common scaling law of non-linear dynamical properties, over a dynamical range of several orders of magnitudes in intensities, implying that many basic X-ray emission nodes or elements are inter-connected over multi-scales. A future high timing and imaging resolution solar X-ray instrument, aimed at isolating and resolving the fundamental elements of solar X-ray lightcurves, may shed new lights onto the fundamental physical mechanisms, which are common in astrophysical systems with vastly different mass and spatial scales. Using the Sun as an astrophysical laboratory, “Applied Solar Astrophysics” will deepen our understanding of many important astrophysical problems.

We present the results of six Suzaku observations of the recurrent black hole transient 4U 1630–472 during its decline from its most recent outburst in 2006. All observations show the typical high/soft state spectral shape in the 2–50 keV band, roughly described by an optically thick disk spectrum in the soft energy band plus a weak power-law tail.

The disk temperature decreases from 1.4 keV to 1.2 keV as the flux decreases by a factor 2, consistent with a constant radius as expected for disk-dominated spectra. All the observations reveal significant absorption lines from highly ionized (H-like and He-like) iron Kα at 7.0 keV and 6.7 keV.

The energies of these absorption lines suggest a blue shift with an outflow velocity of ∼1000 km s−1. The H–like iron Kα equivalent width remains approximately constant at ∼30 eV over all the observations, while that of the He–like Kα line increases from 7 eV to 20 eV. Thus the ionization state of the material decreases, as expected from the decline in flux.

The data constrain the velocity dispersion of the absorber to 200–2000 km s−1, and the size of the plasma as ∼1010 cm assuming a source distance of 10 kpc.

The signatures of intermittent dissipation of turbulent energy have been sought in the translucent environment of a low-mass dense core. Molecular line observations reveal a network of narrow filamentary structures, found on statistical grounds to be the locus of the largest velocity shears. Three independent properties of these structures make them the plausible sites of intermittent dissipation of turbulence: (1) gas there is warmer and more diluted than average, (2) it bears the signatures of a non-equilibrium chemistry triggered by impulsive heating due to turbulence dissipation, and (3) the power that these structures radiate in the gas cooling lines (mostly H2) is so large that it balances the total energy injection rate of the turbulent cascade, for a volume filling factor of only a few percents, consistent with other observations in the Solar Neighborhood. These filamentary structures may act as tiny seeds of gas condensation in diffuse molecular gas. They do not exhibit the properties of steady-state low-velocity magneto-hydrodynamic (MHD) shocks, as presently modelled.

The broad range of dynamics exhibited by plasma motions within the solar interior affects many aspects of the generation and transport of magnetic fields during the solar magnetic activity cycle. On the photosphere, such dynamics include the differential rotation, meridional flows, and a hierarchy of convection cells, and these fluid motions are observed to readily advect any small-scale magnetic fields embedded within them. While the effects of large-scale flows on the global activity cycle are well known, it is becoming increasingly apparent that small-scale dynamics can also affect global magnetic activity throughout the solar cycle. Such effects include variations in the strength of the magnetic dipole moment with time, and the timing of the reversals of the polar-cap flux. In this article, several aspects of this coupling between small and large scales will be illustrated, and the implications of such coupling on the solar activity cycle will be discussed.

We report about the results of the Stellar Evolution Challenge, initiated at the Leiden Lorentz Center meeting “Fine-tuning stellar population models” (June, 2006).

In the quest for a better theoretical understanding of the dynamical processes operating in stellar envelopes, increasingly more realistic hydrodynamical models of stellar convection have been developed over the last 25 years. Based on 3D state-of-the-art simulations performed recently with the radiation hydrodynamics code CO5BOLD, we review the present status of hydrodynamical modeling of stellar surface convection and demonstrate the basic differences between 3D hydrodynamical models and 1D ‘classical’ hydrostatic atmospheres where convection is treated by the mixing-length theory. We briefly discuss some of the many possible applications across the Hertzsprung-Russell diagram, including spectroscopic abundance determinations using 3D stellar atmospheres, particularly with regard to the much debated question of the solar oxygen abundance.

We review the present situation of the formal education in astronomy in the Latin American countries. We have concluded that we can divide the countries into three categories according with the different development of the astronomical careers in astronomy.