Schools of Cosmology and Gravitation

One of the most important contributions accomplished by the Group of Cosmology and Gravitation of the Centro Brasileiro de Pesquisas Físicas (Brazilian Center of Physical Research) towards the development and improvement of Brazilian young physicists is to promote and organize the Brazilian Schools of Cosmology and Gravitation (Escolas Brasileiras de Cosmologia e Gravitação). They were created to constitute a forum of studies and analysis of the main subjects associated to Cosmology, and a quick examination of the historical profile of these events allows one to understand how this idea has been developing since the year of 1978, when the first meeting of this kind took place. Such profile will be presented concisely in the ensuing paragraphs.

Both the I and II Schools (in the years of 1978 and 1979, respectively) were envisaged to become a means of consolidation, for our young physicists, of the knowlegde about the basic structure of the Theory of the Gravitation, as well as of the conceptual tools and mathematical techniques that are required for a deeper understanding of the Theory of the General Relativity and its characterization of the evolutionary structure of space-time. Besides this foundational work, some fundamental concepts of theories related to Gravitation and General Relativity, involving rudiments of Unified Theories and some basic aspects of Relativistic Astrophysics, were also presented.

In the III and IV Schools ( respectively, in 1982 and 1984) the notions of Astrophysics presented at the previous Schools were enlarged. Besides, great attention was given to the study of the Theory of Elementary Particles and its intimate association with the so-called Standard Model of Cosmology - identified with the notion of an explosive and hot beginning of the Universe (known in the literature as the Hot Big Bang Hypothesis).

In the year of 1987, the V School was aimed at enlarging the knowledge and analysis basis presented at the previous Schools, evolving to a wider and deeper discussion of the possible viable alternatives of explaining the behavior in large scale of the universe. On this occasion, courses based on the Standard Model were presented, as well as other courses examining the idea of an Eternal Universe, with neither beginning nor end. Besides these specific approaches, it was possible to examine, in larger detail, the relationship between Quantum Physics and Gravitation. Although this union is still far from being considered complete, in the V School some basic ideas were presented that were later developed in the VI School.

The V School was also the first to be open to the international scientific community: researchers and students of twenty-four (24) countries enrolled in this School. The courses then offered also reflected this internationalization. Soon after, during the two weeks of the VI School, in 1989, the ideas first presented at the previous School were developed in basic courses, with great emphasis given to quantum processes in Cosmology. Such fact constituted an natural evolution of the previous events, reflecting the important paper performed, nowadays, by the study of quantum processes in Cosmology. Besides these courses - with duration of one week each - small workshops were carried out, based on parallel courses. Among these additional events, two were of particular importance: the opening of a seminar session of student participants, promoting in this way a stronger interaction between them and the invited speakers; and the opening of an extraordinary session of debates, in the which the ten invited teachers exposed, individually, their opinion about the main current issues in Cosmology and correlate areas. This experience was so satisfactory that was integrated in the organization of the subsequent Schools.

In the year of 1991, due to financial difficulties of the system of Science and Technology of the country, it was not possible to keep the periodicity of the Schools. However, in order to avoid the harming of an entire generation of young scientists, a small meeting took place in CBPF - a "Mini-school", with a ten-days duration. This Mini-school was attended by 79 students of different Brazilian universities and constituted an important basis for subsequent studies and projects.

In 1993, the VII School was again accomplished in two weeks. Besides presenting a general overview on both the main achievements and the unsolved problems of Cosmology to the day, this School continued - as in the previous ones - the discussion on one of the most formidable questions: the creation of the universe. The great innovation was due to the general change in scientists' attitude with respect to the remote past of our universe: while, until recently, it was attributed to an inaccessible initial explosion the task of generating anf explanation for all ulterior processes of nature, present Physics - in several competitive proposals - endeavors to gain access to the mechanisms of creation, both classical and quantum. Therefore, models of Eternal Universes, without singularity, were discussed in several occasions and by several scientists. There was, however, a general consensus that the universe underwent an extremely hot primordial period. This means that either a process of quantum tunelling or a previous classical colapsing phase should provide for the conditions allowing an era of tremendous matter/energy concentration to take place. Different propositions in this line of reasoning were examined in the courses and seminars of this School.

The VIII School, in 1995, consolidated its international character, not only for counting with speakers of great prestige in the international scientific community, but mainly for the large number of students coming from many countries. In this School, special emphasis was given to quantum processes and their consequences in an expanding Universe. Quantum processes of matter were examined not just in a classical background (semi-classical approach), as different proposals of quantum treatment of the gravitaitional field itself were also presented. Recent attempts of explaining the existence and formation of large structures (galaxies, clusters, etc) were further examined and discussed, either through a more observational and classical perspective, or through elementary quantum processes.

The most recent version of the School (number IX) was carried out in 1998 and celebrated its twenty years of existence. On this occasion Prof. Yvonne Choquet-Bruhat was honored with a tribute delivered by Prof. Werner Israel. The issues of the cosmic microwave background radiation, the thermodynamical properties of black holes and the physics of time machines, among other themes of great interest, were discussed. The next meeting, the X Brazilian School of Cosmology and Gravitation, shall happen in 2002.