This volume contains the lectures presented at the second course of the International School of Space Chemistry held in Erice (Sicily) from October 20 - 30 1991 at the "E. Majorana Centre for Scientific Culture." The course was attended by 58 participants from 13 countries. The Chemistry of Life's Origins is well recognized as one of the most critical subjects of modem chemistry. Much progress has been made since the amazingly perceptive contributions by Oparin some 70 years ago when he first outlined a possible series of steps starting from simple molecules to basic building blocks and ultimate assembly into simple organisms capable of replicating, catalysis and evolution to higher organisms. The pioneering experiments of Stanley Miller demonstrated already forty years ago how easy it could have been to form the amino acids which are critical to living organisms. However we have since learned and are still learning a great deal more about the primitive conditions on earth which has led us to a rethinking of where and how the condition for prebiotic chemical processes occurred. We have also learned a great deal more about the molecular basis for life. For instance, the existence of DNA was just discovered forty years ago.

The book presents the most recent developments of laboratory studies in astrophysics and space research. The individual chapters review laboratory investigations under simulated space conditions, studies for the design of successful space experiments or for supporting the interpretation of astronomical and space mission recorded data. Related theoretical models, numerical simulations and in situ observations demonstrate the necessity of experimental work on the Earth's surface. The expertise of the contributing scientists covers a broad spectrum and is included in general overviews from fundamental science to recent space technology. The book intends to serve as a reference for researchers and graduate students on the most recent activities and results in laboratory astrophysics, and to give reviews of their applications in astronomy, planetology, cosmochemistry, space research and Solar System exploration.

This volume contains the lectures presented at the first course of the Inter national School of Space Chemistry held in Erice (Sicily) from May 10 to May 20 at the 'E. Majorana Centre for Scientific Culture'. The course was attended by 57 participants from 11 countries. The recognition by Professor A. Zichichi that space chemistry is one of the important and rapidly growing scientific disciplines with many and varied appli cations provided the stimulation to initiate this new school. Historically, the study of chemistry in space had its major origins in comets, the solar nebula and circumstellar envelopes before the interstellar medium achieved its current prominence. A remarkably rapid development in interstellar chemistry was precipitated by the discovery of formaldehyde in the late 1960's made possible by the new radio observational techniques. A four atom molecule in interstellar space was indeed a surprise considering that only a short time ear lier there were still arguments about the existence of the simplest of all molecules - the hydrogen molecule. The application of ion-molecule reactions to interstellar cloud chemistry provided a rich variety of new possibilities which were, however, continuously under pressure to keep pace with radio-astronomical discoveries of more and more complex molecules."

The fundamentals of astrochemistry in the gas phase are relatively well established, in contrast to the special relevance attributed to processes involving interstellar dust grains - the solid component of matter diffused among the stars.
This book presents the state of the art in relation to the ways grains interact with gases, the catalytic role played by dust that allows key molecular species (H2 as well as many complex, possibly prebiotic species) to be formed on its surface - which cannot be obtained efficiently by any other mechanisms, and the interaction between solids (dust grains, icy mantles, cometary nuclei, satellites of the giant planets and minor bodies in the Solar system) in space and energetic agents such as UV photons and fast particles.
The presence and importance of PAH, which may represent the smallest component of the grains, is considered in relation to possible astrobiological pathways and the ever-present mystery of the ubiquitous presence of Diffuse Interstellar Bands and their carriers.

The fundamentals of astrochemistry in the gas phase are relatively well established, in contrast to the special relevance attributed to processes involving interstellar dust grains - the solid component of matter diffused among the stars.
This book presents the state of the art in relation to the ways grains interact with gases, the catalytic role played by dust that allows key molecular species (H2 as well as many complex, possibly prebiotic species) to be formed on its surface - which cannot be obtained efficiently by any other mechanisms, and the interaction between solids (dust grains, icy mantles, cometary nuclei, satellites of the giant planets and minor bodies in the Solar system) in space and energetic agents such as UV photons and fast particles.
The presence and importance of PAH, which may represent the smallest component of the grains, is considered in relation to possible astrobiological pathways and the ever-present mystery of the ubiquitous presence of Diffuse Interstellar Bands and their carriers.

The book presents the most recent developments of laboratory studies in astrophysics and space research. The individual chapters review laboratory investigations under simulated space conditions, studies for the design of successful space experiments or for supporting the interpretation of astronomical and space mission recorded data. Related theoretical models, numerical simulations and in situ observations demonstrate the necessity of experimental work on the Earth's surface. The expertise of the contributing scientists covers a broad spectrum and is included in general overviews from fundamental science to recent space technology. The book intends to serve as a reference for researchers and graduate students on the most recent activities and results in laboratory astrophysics, and to give reviews of their applications in astronomy, planetology, cosmochemistry, space research and Solar System exploration.

The now recognized extensive existence of life on earth very shortly after the destructive bombardment of the earth's surface by early solar system debris has stimulated inquiry into possible exogenous sources of prebiotic molecules from space as well as intensified studies of the early earth's atmosphere. The chapters in this book cover the possible sources of prebiotic molecules and avenues by which life could have evolved, starting from the birth and evolution of the solar system. The relevance of the classic experiments by Stanley Miller on the formation of life's building blocks on an early earth is reexamined. The role of chemistry in space is covered by chapters on interstellar dust, and meteorites to which experimental as well as theoretical investigations have been directed. In various chapters the existence of amino acids as well as other prebiotic molecules in meteorites is clearly established and inferred for interstellar dust and comets. Theories of molecular synthesis in the solar nebula are considered. Extensive coverage is given to the physical conditions and to prebiotic systems on the early earth. Possible pathways to life on an early Mars and the possible messages to be obtained by space exploration are discussed. Questions of effects of clays and of chirality on early chemical evolution are discussed. Recent ideas on the RNA world as the precursor to life are reviewed. The open-endedness of the study of life's origins and the need to investigate whether the prebiotic building blocks formed in outer space or on the earth is emphasized. A good deal of the book is suitable to graduate students.

This volume contains the lectures presented at the first course of the Inter national School of Space Chemistry held in Erice (Sicily) from May 10 to May 20 at the 'E. Majorana Centre for Scientific Culture'. The course was attended by 57 participants from 11 countries. The recognition by Professor A. Zichichi that space chemistry is one of the important and rapidly growing scientific disciplines with many and varied appli cations provided the stimulation to initiate this new school. Historically, the study of chemistry in space had its major origins in comets, the solar nebula and circumstellar envelopes before the interstellar medium achieved its current prominence. A remarkably rapid development in interstellar chemistry was precipitated by the discovery of formaldehyde in the late 1960's made possible by the new radio observational techniques. A four atom molecule in interstellar space was indeed a surprise considering that only a short time ear lier there were still arguments about the existence of the simplest of all molecules - the hydrogen molecule. The application of ion-molecule reactions to interstellar cloud chemistry provided a rich variety of new possibilities which were, however, continuously under pressure to keep pace with radio-astronomical discoveries of more and more complex molecules."