Cadernos de Astronomia

Galaxies are large star systems, containing hundreds of millions to hundreds of billions of stars. Its dimensions range from a few to tens of kiloparsecs. These immense cosmic structures are separated by distances that can reach megaparsecs, and a large galaxy can be surrounded by smaller satellite galaxies. Furthermore, they can form gravitationally bound systems containing from dozens to thousands of galaxies. Understanding the distribution of galaxies in the universe constitutes one of the greatest challenges for universe models. This issue of the Cadernos de Astronomia aims to provide a broad overview of what we understand and how much remains to be understood about these intriguing astronomical objects. The texts are written in such a way that they can be read by laypeople who want to know something about this vast topic, as well as by students and researchers in astrophysics and cosmology who wish to have a general overview of current research into galaxies.

In other sections of CdA, topics such as astrophotography, exoplanets, gravitational lenses, the materialism-idealism dichotomy in physics, Amoroso Costa's contribution to science in Brazil, the space race between the USA and USSR, among others, are covered. In its technical notes, the CdA also pays tribute to the Russian cosmologist Alexey Starobinsky and the Italian-Brazilian physicist Ennio Candotti, who recently passed away, and who left us legacies of extreme relevance in their respective areas of activity.