Galaxies have a history. This has become clear from recent sky surveys which have shown that distant galaxies, formed early in the life of the Universe, differ from the nearby ones. New observational windows at ultraviolet, infrared and millimetric wavelengths (provided by ROSAT, IRAM, IUE, IRAS, ISO) have revealed that galaxies contain a wealth of components: very hot gas, atomic hydrogen, molecules, dust, dark matter ...

A significant advance is expected due to new instruments (VLT, FIRST, XMM) which will allow one to explore the most distant Universe. Three Euroconferences have been planned to punctuate this new epoch in galactic research, bringing together specialists in various fields of Astronomy.

The first one, held in Granada (Spain) in May 2000, addressed the observational clues. The second one took place in October 2001 in St Denis de la Reunion (France) and reviewed the basic building blocks and small-scale processes in galaxy evolution. The third one will take place in July 2002 in Kiel (Germany) and will be devoted to the overall modelling of galaxy evolution. This book contains the proceedings of the second conference. It is suitable for researchers and PhD students in Astrophysics. "

Chaos theory plays an important role in modern physics and related sciences, but -, the most important results so far have been obtained in the study of gravitational systems applied to celestial mechanics. The present set of lectures introduces the mathematical methods used in the theory of singularities in gravitational systems, reviews modeling techniques for the simulation of close encounters and presents the state of the art about the study of diffusion of comets, wandering asteroids, meteors and planetary ring particles. The book will be of use to researchers and graduate students alike.

This book was conceived during the Workshop "Calibration and Orientation of Cameras in Computer Vision" at the XVIIth Congress of the ISPRS (In ternational Society of Photogrammetry and Remote Sensing), in July 1992 in Washington, D. C. The goal of this workshop was to bring photogrammetry and computer vision experts together in order to exchange ideas, concepts and approaches in camera calibration and orientation. These topics have been addressed in photogrammetry research for a long time, starting in the sec ond half of the 19th century. Over the years standard procedures have been developed and implemented, in particular for metric cameras, such that in the photogrammetric community such issues were considered as solved prob lems. With the increased use of non-metric cameras (in photogrammetry they are revealingly called "amateur" cameras), especially CCD cameras, and the exciting possibilities of acquiring long image sequences quite effortlessly and processing image data automatically, online and even in real-time, the need to take a new and fresh look at various calibration and orientation issues became obvious. Here most activities emerged through the computer vision commu nity, which was somewhat unaware as to what had already been achieved in photogrammetry. On the other hand, photogrammetrists seemed to ignore the new and interesting studies, in particular on the problems of orienta tion, that were being performed by computer vision experts."

It was with pleasure that CAUP became for three days the core to the cloud of star formation experts all over the world. Close to the celebration of its 15th anniversary - therefore still in the early stages of institutional evolution - we are proud of our multiple activities in Astronomy: a productive research centre, classi?ed as "Institution of excellence" within the Portuguese research units, but also an "Institution of Public Utility" as recognised by the Government. Fifteen years ago we choose to play a role not only in research, as expected from any research centre but also in the training of the future astronomers and the promotion of science and scienti?c culture. This choice is clearly stated in our by-laws and also in the multiple activities we have carried out since. Along the years we have organized on a regular basis international Workshops similar to "Cores to Clusters." Sometimes we have chosen to organize int- national conferences of a larger size. On other occasions the choice has been for smaller and more informal discussion meetings. Or even doctoral schools with very different objectives. In common all those meetings have always had, besides the formal registered participants, a group of informal participants, our undergraduate students of Astronomy, so eager to be in touch with the real world.

Galaxies have a history. This has become clear from recent sky surveys, which have shown that distant galaxies, formed early in the life of the Universe, differ from the nearby ones. New observational windows at ultraviolet, infrared and millimetric wavelengths (provided by ROSAT, IRAM, IUE, IRAS, ISO) have revealed that galaxies contain a wealth of components: very hot gas, atomic hydrogen, molecules, dust, dark matter. A significant advance is expected due to new instruments (VLT, FIRST, XMM) which will allow one to explore the most distant Universe. Three Euroconferences have been planned to punctuate this new epoch in galactic research, bringing together specialists in various fields of Astronomy. The first, held in Granada (Spain) in May 2000, addressed the observational clues. The second will take place in October 2001 in St Denis de la Reunion (France) and will review the basic building blocks and small-scale processes in galaxy evolution. The third will take place in July 2002 in Kiel (Germany) and will be devoted to the overall modelling of galaxy evolution. This book contains the proceedings of the first conference. It is recommended to researchers and PhD students in Astrophysics."

Some fifty years ago as a cub reporter, Barbree caught space fever the night that Sputnik passed over Albany, Georgia. On a double date where the couples actually did some star gazing, Barbree recognized that exploring space would become one of the most important stories of the century. Convinced that one day astronauts would walk on the moon, Barbree moved to the then sleepy ocean-side community of Cocoa Beach, right outside Cape Canaveral, and began reporting on rockets that soared, exploded, and fizzled. In the decades to come he witnessed a parade of history as space pioneers, hucksters, groupies and politicians participated in the greatest show of technology the world had ever seen. In "Live from Cape Canaveral", Barbree offers his unique perspective on the space program. Warm and perceptive, he reminds us just how thrilling the great moments of the space race were and why America fell in love with its heroic, sometimes larger-than-life astronauts.

Based on material delivered at several summer schools, this book is the first comprehensive textbook at the graduate level encompassing all aspects associated with the emerging field of astrobiology.

Volume II gathers another set of extensive lectures covering topics so diverse as the formation and the distribution of elements in the universe, the concept of habitability from both the planetologists' and the biologists' point of view and artificial life. The contributions are held together by the common goal to understand better the origin of life, its evolution and possible existence outside the Earth's realm.
The volume ends with 120 pages of a very useful appendix comprising "Some Astrophysical Reminders," "Useful Astrobiological Data" and "An Astrobiological Glossary."

Here is a fascinating text that integrates topics pertaining to all scales of the MHD-waves, emphasizing the linkages between the ULF-waves below the ionosphere on the ground and magnetospheric MHD-waves. It will be most helpful to graduate and post-graduate students, familiar with advanced calculus, who study the science of MHD-waves in the magnetosphere and ionosphere. The book deals with Ultra-Low-Frequency (ULF)-electromagnetic waves observed on the Earth and in Space.

This book reviews the current state of knowledge of the atmospheres of the giant gaseous planets: Jupiter, Saturn, Uranus, and Neptune. The current theories of their formation are reviewed and their recently observed temperature, composition and cloud structures are contrasted and compared with simple thermodynamic, radiative transfer and dynamical models. The instruments and techniques that have been used to remotely measure their atmospheric properties are also reviewed, and the likely development of outer planet observations over the next two decades is outlined.
This second edition has been extensively updated following the Cassini mission results for Jupiter/Saturn and the newest ground-based measurements for Uranus/Neptune as well as on the latest development in the theories on planet formation.

In Human Missions to Mars Donald Rapp looks at human missions to Mars from an engineering perspective. He begins by describing the pros and cons of robotic exploration versus human exploration and then examines the ideas for sending humans to Mars from the point of view of both the enthusiast and the skeptic. Chapter 2 describes how space missions are planned and how they may be achieved as a sequence of separate steps. Chapter 3 deals with the complex issues relating to the outward journey to Mars and the return leg. The author deals with propulsion systems and with the analysis of the various trajectories which may be utilized for such a mission. He divides mission into a number of stages: Earth s surface to low-Earth orbit (LEO); departing from LEO; Mars orbit insertion and landing; ascent from Mars; trans-Earth injection from Mars orbit and Earth orbit insertion and landing. Chapter 4 discusses a wide range of elements critical to a human Mars mission, including life support consumables, radiation effects and shielding, microgravity effects, abort options and mission safety, possible habitats on the Martian surface and aero assisted orbit insertion and entry decent and landing.

For any human mission to the Red Planet the possible utilization of any resources indigenous to Mars would be of great value and such possibilities are discussed in Chapter 5. The use of indigenous resources on the Moon is described as a precursor to the availability of similar resources on Mars and issues such as fuelling Mars-bound craft from lunar resources, the use of lunar ferries, staging, assembly and refueling in near-Earth space are all discussed. The important applications arising from the transportation of hydrogen to Mars are also described. Chapter 6 deals with a range of previous Mars mission studies and the technologies they employed. Chapter 7 looks as how NASA is planning for its return to the Moon, and the use of the Moon as a stepping stone to Mars. Chapter 8 presents the author s detailed analysis of why, in his opinion, the current NASA approach will fail to send humans to Mars before 2080. The book concludes with three appendices describing the use of solar energy on the Moon and on Mars and the value of indigenous water on Mars."

Understanding how the Sun changes though its 11-year sunspot cycle and how these changes affect the vast space around the Sun the heliosphere has been one of the principal objectives of space research since the advent of the space age. This book presents the evolution of the heliosphere through an entire solar activity cycle. The last solar cycle (cycle 23) has been the best observed from both the Earth and from a fleet of spacecraft. Of these, the joint ESA-NASA Ulysses probe has provided continuous observations of the state of the heliosphere since 1990 from a unique vantage point, that of a nearly polar orbit around the Sun. Ulysses results affect our understanding of the heliosphere from the interior of the Sun to the interstellar medium - beyond the outer boundary of the heliosphere. Written by scientists closely associated with the Ulysses mission, the book describes and explains the many different aspects of changes in the heliosphere in response to solar activity. In particular, the authors describe the rise in solar activity from the last minimum in solar activity in 1996 to its maximum in 2000 and the subsequent decline in activity."

This volume, published in honor of Prof. Luigi Crocco, appears when Luigi Crocco celebrates his 75th birthday of a life devoted to study, research, and teaching. The events in his life and World War II forced Luigi Crocco, as well as other Italian scientists, to look to foreign countries for the calm haven so vital to study. This notwithstanding, his scientific activity was never inter rupted, and this volume is an acknowledgment of scientists and researchers to his work and life. Prefazione Questo volume in onore del prof. ing. Luigi Crocco vede la luce quando Luigi Crocco compie i 75 anni di una vita dedicata allo studio, alia ricerca e all'insegnamento. a Le vicende della vita, ed anche della 2 guerra mondiale, hanno costretto Luigi Crocco, come altri scienziati italiani, a dover cercare in altri Paesi quella serenita necessaria per dedicarsi allo studio. Ma la sua attivita scientifica non ha avuto interruzioni e questo volume essere la testimonianza di studiosi e di ricercatori alia sua opera e alia sua vita."

An understandable perspective on the types of space propulsion systems necessary to enable low-cost space flights to Earth orbit and to the Moon and the future developments necessary for exploration of the solar system and beyond to the stars.

This is the first collection of review articles in one volume covering the very latest developments in exoplanet research. This edited, multi-author volume will be an invaluable introduction and reference to all key aspects in the field this field. The reviews cover topics such as the properties of known exoplanets and searching for exoplanets in the stellar graveyard. The book provides an easily accessible point of reference in a fast moving and exciting field.

As a star in the universe, the Sun is constantly releas- cover a wide range of time and spatial scales, making ?? ing energy into space, as much as ?. ? ?? erg/s. Tis observations in the solar-terrestrial environment c- energy emission basically consists of three modes. Te plicated and the understanding of processes di?cult. ?rst mode of solar energy is the so-called blackbody ra- In the early days, the phenomena in each plasma diation, commonly known as sunlight, and the second region were studied separately, but with the progress mode of solar electromagnetic emission, such as X rays of research, we realized the importance of treating and UV radiation, is mostly absorbed above the Earth's the whole chain of processes as an entity because of stratosphere. Te third mode of solar energy emission is strong interactions between various regions within in the form of particles having a wide range of energies the solar-terrestrial system. On the basis of extensive from less than ? keV to more than ? GeV. It is convenient satellite observations and computer simulations over to group these particles into lower-energy particles and thepasttwo decades, it hasbecomepossibleto analyze higher-energy particles, which are referred to as the so- speci?cally the close coupling of di?erent regions in the lar wind and solar cosmic rays, respectively. solar-terrestrial environment.

Professor Kondratyev and his team consider the concept of global warming due to the greenhouse effect and put forward a new approach to the problem of assessing the impact of anthropogenic processes. Considering data on both sources and sinks for atmospheric carbon and various conceptual schemes of the global carbon dioxide cycle, they suggest a new approach to studies of the problem of the greenhouse effect. They assess the role of different types of soil and vegetation in the assimilation of carbon dioxide from the atmosphere, and discuss models of the atmosphere ocean gas exchange and its role in the carbon dioxide cycle, paying special attention to the role of the Arctic Basin. The authors also consider models of other global atmospheric cycles for a range of atmospheric constituents, and conclude by drawing together a range of scenarios on modelling the global carbon cycle.

Studying the complex physical systems of stellar jets necessitates the incorporation of nonlinear effects which occur on a wide variety of length and timescales. One of the primary methods used to study the physics of jets is numerical simulations that apply high performance computing techniques. Such techniques are also required for analysing the huge modern astrophysical datasets. This book examines those computing techniques. It is a collection of the lectures from the fifth and final school of the JETSET network, "Jets From Young Stars V: High Performance Computing in Astrophysics." It begins with an introduction to parallel programming techniques, with an emphasis on Message Passing Interface (MPI), before it goes on to review grid technology techniques and offer a practical introduction to Virtual Observatory. The second half of the book, then, is devoted to applications of high performance computing techniques, including 3D radiation transfer, to jet and star formation processes. Aimed at graduate students in astrophysics, this book presents state-of-the-art methods, thereby offering interesting new insights to researchers in the field.

TheideafortheselectureseriesaroseataWorkshoponsolarphysicswhichwas heldattheInterUniversityCentreforAstronomyandAstrophysics(IUCAA), Pune/IndiainDecember2000. ThisWorkshopaimedtopresentacompreh- siveandup-to-dateoverviewofsolarphysicsforinterestedstudentsandfaculty inotherbranchesofastrophysics. Itwasintendedtoshowthatthis?eld,c- centratingonourcloseststar,isavitalandexciting?eldofresearch. Forthis purposeanumberofcomprehensivereviewswereorganisedwhichassumedthat theaudiencewouldhaveonlyabasicphysicsbackgroundbuthadnoprior knowledgeaboutsolarphysics. Thesetoflecturescoveredtopicsrangingfrom thesolarcoretotheconvectionzone,thephotosphere,chromosphere,andcorona andextendingtothesolarwindintheinterplanetarymedium DuringandaftertheWorkshoptherewasmuchenthusiasmforthisform ofpresentationanditwasfeltthattheselectures,augmentedbyincludingthe latestresearch?ndingsinthe?eld,wouldbebene?cialtoamuchlargeraudience. Thustheplanforthisbookoriginatedwhichcouldthenberealisedthanksto thepublishers,Springer-Verlag. Thereare9articlesbasedonthelecturesgivenattheWorkshop. Thearticle byChitreon"OverviewofSolarPhysics"givesanintroductiontothewhole varietyofphenomenaofsolarphysics,theproblemsandtheirsolutionsand salientresults. Thearticleon"InstrumentationandObservationaltechniques relatedtoSolarPhysics"byBhatnagardescribesindetailtheprinciplesof- larinstrumentationnormallyusedtotakesimplewhitelight,monochromatic andspectroscopicobservations. Practicalmethodstomeasureimportantbasic parameters,likearea,positionandtheclassi?cationofsunspotsaredescribed indetail. Antia'sarticleon"SolarInteriorandSeismology"describesthesolar interior,thetechniqueofhelioseismologyandhowthisnewtechniqueallowsa determinationoftheinternalstructureanddynamicsoftheSunandconstrains theoriesofstellarstructure,evolutionandangularmomentumtransport. - bastha'sarticleon"TheActiveandExplosiveSun"givesanoverviewofhighly time-dependentphenomenainthephotosphere,chromosphereandcoronaofthe Sunandprovidessometheoreticalmodelsofthesolar?ares. Hasan'sarticle on"MagneticFluxTubesandActivityontheSun"discussesthegeneration, storageandemergenceofmagnetic?eldsintheformofsmall-scale?uxtubes andexaminestheirroleinheatingofthechromosphere. Ventakrishan'sar- cleon"SolarMagneticFields"givesatheoreticaloverviewofthegeneration VI Preface ofmagnetic?eldsbythedynamomechanism,thegeneralmagnetic?eldtop- ogyandhowthemagnetic?eldsaremeasured. Ulmschneider'scontributionon "ThePhysicsofChromospheresandCoronae"discusseswhyallstarslikethe Sunhavehotouterchromosphericandcoronallayers. Itidenti?estheheating mechanismsanddynamicalprocesseswhichtakeplacebothinthepresenceand absenceofmagnetic?elds. ThearticlebyDwivedion"TheSolarCorona"gives ageneraloverviewofthesolarcorona,howitisobservedandwhatthephy- calprocessesleadingtoitsformationare. FinallyManoharan'scontributionon "TheSolarWind"describesthegenerationandmeasurementofthesolarwind derivedfrominsituobservationsbyspacecraftandinterplanetaryscintillation studies. Wehopethatbyreadingtheselectures,interestedpeople,amateurs,graduate andpostgraduatestudentswillbemotivatedtotakeupsolarphysicsasanarea ofresearch,andshareourexcitementaboutthewondersofourneareststar- theSun. WearethankfultoT. PadmanabhanandtheInterUniversityCentrefor AstronomyandAstrophysics,PunefororganisingandhostingthisWorkshop onSolarPhysics. Mumbai,Udaipur,Heidelberg H. M. Antia February2003 A. Bhatnagar P. Ulmschneider ListofContributors AshokAmbastha S. S. Hasan Udaipur Solar Observatory Indian Institute of Astrophysics Physical Research Laboratory Bangalore560034,India P. O. Box No. 198 hasan@iiap. ernet. in Udaipur313001,India ambastha@prl. ernet. in P. K. Manoharan Radio Astronomy Centre H. M. Antia Tata Institute Tata Institute of Fundamental Research of Fundamental Research P. O. Box 8 Homi Bhabha Road Udhagamandalam (Ooty) 643001, Mumbai400005,India India antia@tifr. res. in mano@racooty. ernet. in ArvindBhatnagar Udaipur Solar Observatory P. Ulmschneider Physical Research Laboratory Institut fur TheideafortheselectureseriesaroseataWorkshoponsolarphysicswhichwas heldattheInterUniversityCentreforAstronomyandAstrophysics(IUCAA), Pune/IndiainDecember2000. ThisWorkshopaimedtopresentacompreh- siveandup-to-dateoverviewofsolarphysicsforinterestedstudentsandfaculty inotherbranchesofastrophysics. Itwasintendedtoshowthatthis?eld,c- centratingonourcloseststar,isavitalandexciting?eldofresearch. Forthis purposeanumberofcomprehensivereviewswereorganisedwhichassumedthat theaudiencewouldhaveonlyabasicphysicsbackgroundbuthadnoprior knowledgeaboutsolarphysics. Thesetoflecturescoveredtopicsrangingfrom thesolarcoretotheconvectionzone,thephotosphere,chromosphere,andcorona andextendingtothesolarwindintheinterplanetarymedium DuringandaftertheWorkshoptherewasmuchenthusiasmforthisform ofpresentationanditwasfeltthattheselectures,augmentedbyincludingthe latestresearch?ndingsinthe?eld,wouldbebene?cialtoamuchlargeraudience. Thustheplanforthisbookoriginatedwhichcouldthenberealisedthanksto thepublishers,Springer-Verlag. Thereare9articlesbasedonthelecturesgivenattheWorkshop. Thearticle byChitreon"OverviewofSolarPhysics"givesanintroductiontothewhole varietyofphenomenaofsolarphysics,theproblemsandtheirsolutionsand salientresults. Thearticleon"InstrumentationandObservationaltechniques relatedtoSolarPhysics"byBhatnagardescribesindetailtheprinciplesof- larinstrumentationnormallyusedtotakesimplewhitelight,monochromatic andspectroscopicobservations. Practicalmethodstomeasureimportantbasic parameters,likearea,positionandtheclassi?cationofsunspotsaredescribed indetail. Antia'sarticleon"SolarInteriorandSeismology"describesthesolar interior,thetechniqueofhelioseismologyandhowthisnewtechniqueallowsa determinationoftheinternalstructureanddynamicsoftheSunandconstrains theoriesofstellarstructure,evolutionandangularmomentumtransport. - bastha'sarticleon"TheActiveandExplosiveSun"givesanoverviewofhighly time-dependentphenomenainthephotosphere,chromosphereandcoronaofthe Sunandprovidessometheoreticalmodelsofthesolar?ares. Hasan'sarticle on"MagneticFluxTubesandActivityontheSun"discussesthegeneration, storageandemergenceofmagnetic?eldsintheformofsmall-scale?uxtubes andexaminestheirroleinheatingofthechromosphere. Ventakrishan'sar- cleon"SolarMagneticFields"givesatheoreticaloverviewofthegeneration VI Preface ofmagnetic?eldsbythedynamomechanism,thegeneralmagnetic?eldtop- ogyandhowthemagnetic?eldsaremeasured. Ulmschneider'scontributionon "ThePhysicsofChromospheresandCoronae"discusseswhyallstarslikethe Sunhavehotouterchromosphericandcoronallayers. Itidenti?estheheating mechanismsanddynamicalprocesseswhichtakeplacebothinthepresenceand absenceofmagnetic?elds. ThearticlebyDwivedion"TheSolarCorona"gives ageneraloverviewofthesolarcorona,howitisobservedandwhatthephy- calprocessesleadingtoitsformationare. FinallyManoharan'scontributionon "TheSolarWind"describesthegenerationandmeasurementofthesolarwind derivedfrominsituobservationsbyspacecraftandinterplanetaryscintillation studies. Wehopethatbyreadingtheselectures,interestedpeople,amateurs,graduate andpostgraduatestudentswillbemotivatedtotakeupsolarphysicsasanarea ofresearch,andshareourexcitementaboutthewondersofourneareststar- theSun. WearethankfultoT. PadmanabhanandtheInterUniversityCentrefor AstronomyandAstrophysics,PunefororganisingandhostingthisWorkshop onSolarPhysics. Mumbai,Udaipur,Heidelberg H. M. Antia February2003 A. Bhatnagar P. Ulmschneider ListofContributors AshokAmbastha S. S. Hasan Udaipur Solar Observatory Indian Institute of Astrophysics Physical Research Laboratory Bangalore560034,India P. O. Box No. 198 hasan@iiap. ernet. in Udaipur313001,India ambastha@prl. ernet. in P. K. Manoharan Radio Astronomy Centre H. M. Antia Tata Institute Tata Institute of Fundamental Research of Fundamental Research P. O. Box 8 Homi Bhabha Road Udhagamandalam (Ooty) 643001, Mumbai400005,India India antia@tifr. res. in mano@racooty. ernet. in ArvindBhatnagar Udaipur Solar Observatory P. Ulmschneider Physical Research Laboratory Institut fur .. Theoretische Astrophysik P. O. Box No. 198 Univ. Heidelberg Udaipur313001,India Tiergartenstr. 15 arvind@prl. ernet. in 69121Heidelberg,Germany ulm@ita. uni-heidelberg. de S. M. Chitre Department of Physics University of Mumbai P. Venkatakrishnan Mumbai400098,India Udaipur Solar Observatory kumarchitre@hotmail. com Physical Research Laboratory P. O. Box No. 198 BholaN. Dwivedi Udaipur313001,India Department of Applied Physics pvk@prl. ernet. in Institute of Technology Banaras Hindu University Varanasi221005,India dwivedi@banaras. ernet. in TableofContents OverviewofSolarPhysics S. M. Chitre...1 1 Introduction...1 2 CompositionandStructureoftheSun...3 2. 1 EquationsofStellarStructure...4 2. 2 TheStandardSolarModel...7 3 ProbesoftheSun'sInterior...10 3. 1 SolarNeutrinoProblem...

Planetary nebulae are the classic subject of astrophysics. The physical pro cesses occurring in this highly ionized gaseous medium, the formation of emis sion lines in clearly specified conditions, the continuous emission extending from the far ultraviolet up to infrared and radio frequencies, the generation of exotic forms of radiation predicted by atomic physics, along with methods for deciphering the observed spectra and detecting physical and kinematic parameters of the radiating medium, etc. - all these problems form the solid foundations of the physical theory of gaseous nebulae. They are an essential part of the arsenal of powerful tools and concepts without which one cannot imagine understanding and interpreting the enormous diversity of processes taking place in the Universe - in gaseous envelopes surrounding the stars of various classes, from cool dwarfs and flare stars up to hot supergiants, as well as in stellar chromospheres and coronae, in atmospheres of unstable and anomalous stars, in circumstellar clouds and gaseous shells born in nova and supernova explosions, in diffuse nebulae and the interstellar medium, in interacting binary systems, in galaxies with emission lines, in quasars, etc. The last thirty years have seen a turning-point in our knowledge concern ing the very nature of planetary nebulae (PNs). The radio emission of PNs was discovered after it was predicted theoretically. On the other hand, the powerful infrared emission discovered both in the continuum and in emission lines was never expected."

New and more accurate techniques for satellite gravimetry will be available soon, with promising applications in Earth sciences. With this special issue the authors want to stimulate discussion among Earth scientists on objectives and preferences for future satellite gravimetry missions. This is an urgently needed discussion. Visions for follow-on missions have to be developed today, if they are to be realized within 10 years, given the required preparation time of such satellite missions.

The last two years have witnessed a continuation in the breakthrough shift toward pulse tube cryocoolers for long-life, high-reliability cryocooler applications. New this year are papers de scribing the development of very large pulse tube cryocoolers to provide up to 1500 watts of cooling for industrial applications such as cooling the superconducting magnets of Mag-lev trains, coolmg superconducting cables for the power mdustry, and liquefymg natural gas. Pulse tube coolers can be driven by several competing compressor technologies. One class of pulse tube coolers is referred to as "Stirling type" because they are based on the linear Oxford Stirling-cooler type compressor; these generally provide coolmg m the 30 to 100 K temperature range and operate ^t frequencies from 30 to 60 Hz. A second type of pulse tube cooler is the so-called "Gifford-McMahon type. " Pulse tube coolers of this type use a G-M type compressor and lower frequency operation (~1 Hz) to achieve temperatures in the 2 to 10 K temperature range. The third type of pulse tube cooler is driven by a thermoacoustic oscillator, a heat engine that functions well in remote environments where electricity is not readily available. All three types are described, and in total, nearly half of this proceedings covers new developments in the pulse tube arena. Complementing the work on low-temperature pulse tube and Gifford-McMahon cryocoolers is substantial continued progress on rare earth regenerator materials.

Dark matter research is one of the most fascinating and active fields among current high-profile scientific endeavours. It holds the key to all major breakthroughs to come in the fields of cosmology and astroparticle physics. The present volume is particularly concerned with the sources and the detection of dark matter and dark energy in the universe and will prove to be an invaluable research tool for all scientists who work in this field.

In these lectures, I have discussed a number of basic concepts that provide the necessary background to the current studies of star formation. A ?rst partwas dedicatedto illustrate the conceptofa protostar, discussing con- tions and propertiesof the collapseof a molecular core. A secondpart deals with circumstellardisks. Disks areimportantnot only to the processofstar formation itself, but also because they are in all probability the site where planets form. The age range of pre-main-sequence stars coincides with the timescales for the formation of very large planetesimals, the building blocks of planets. Studies ofdisk properties in pre-main-sequencestars ofdi?erent age, located in star-forming regions of di?erent properties, may shed light on the characteristics of planet formation processes. ISO observations can provide important (in some cases, unique) inf- mation on the various stages of the star and planet formation. I have illustrated in detail some examples, when, to my knowledge, ISO data had been reduced and analyzed. Many other programs exist, and will certainly contribute to our understanding of star formation in the near future