A revista Cadernos de Astronomia é uma publicação semestral do Núcleo Cosmo-Ufes da Universidade Federal do Espírito Santo e que conta também com recursos humanos do Centro Brasileiro de Pesquisas Físicas e da Universidade Federal de Ouro Preto (vide o Corpo Editorial). Propõe-se a publicar artigos destinados à divulgação científica, história da ciência, ensino e pesquisa em astronomia e áreas correlatas. O objetivo é tornar acessível a um amplo público, que inclui estudantes secundários, graduandos e simpatizantes da área, o conhecimento científico relacionado à astronomia, cosmologia e gravitação. Possuindo acesso totalmente gratuito, cada número dedica uma seção inteira a um tema específico, onde especialistas nacionais e internacionais discutem em detalhes aspectos qualitativos e quantitativos do tópico em questão. A partir de 2023 os números semestrais dos CdA serão publicados nos meses de Março e Setembro. Cada um desses números possuem datas limite para receber submissões: Números publicados em Março - Submissões feitas até 10 de Janeiro; Números publicados em Setembro - Submissões feitas até 1º de Julho. Submissões recebidas após as datas limite acima não terão garantias de que, uma vez aceitas para publicação, façam parte do próximo número. Não sendo publicadas no próximo número, elas são automaticamente programadas para publicação no número subsequente a ser lançado.
Editorial information of the 6th volume, issue 2, from Cadernos de Astronomia (2025). Copyright page, Letter to Readers and Table of Contents.
Copyright (c) 2025 Os Editores https://creativecommons.org/licenses/by/4.0
Niède Guidon, Serra da Capivara and celestial records in rock art: science, culture and archaeoastronomy in the Piauí caatinga
This article explores the trajectory of archaeologist Niède Guidon and her scientific-cultural legacy based on her discoveries in Serra da Capivara, Piauí. Based on her contribution to Brazilian archaeology and the importance of Serra da Capivara National Park as a world heritage site, we discuss the role of science and education in preserving historical memory and valuing indigenous cultures. Finally, we analyze the archaeoastronomical potential of the region's rock paintings, exploring the possible relationship between prehistoric graphic records and celestial observations of its ancient inhabitants. The analysis adopts an interdisciplinary perspective, integrating archaeology, cultural astronomy and history of science.
Divulgação Científica, Ciência e Sociedade
Copyright (c) 2025 Viviana Borges Corte, Rizalva dos Santos Cardoso Rabelo https://creativecommons.org/licenses/by/4.0
<pre id="tw-target-text" class="tw-data-text tw-text-large tw-ta" dir="ltr" tabindex="-1" role="text" data-placeholder="Tradução" data-ved="2ahUKEwiM24zG16uQAxU6rJUCHVvwJVoQ3ewLegQIDBAV" aria-label="Texto traduzido: Brief comments by Brazilian physicists Ulysses Câmara da Silva (Federal University of Espírito Santo), Nelson Pinto Neto (Brazilian Center for Physics Research), and Olival Freire (Federal University of Bahia) on the 2025 Nobel Prize in Physics, which highlights work demonstrating quantum properties in non-microscopic systems.">Brief comments by Brazilian physicists Ulysses Câmara da Silva (Federal University of Espírito Santo), Nelson Pinto Neto (Brazilian Center for Physics Research), and Olival Freire (Federal University of Bahia) on the 2025 Nobel Prize in Physics, which highlights work demonstrating quantum properties in non-microscopic systems.
Copyright (c) 2025 Júlio C. Fabris https://creativecommons.org/licenses/by/4.0
Explanatory note about the so-called little red dots (LRDs), observed by the James Webb Telescope. These compact, high-mass objects would have formed at a time when the universe was still quite young, which raises questions within the scientific community, since there wouldn't be enough time for objects with such pronounced reddish brightness, characteristic of old galaxies, to form.
Copyright (c) 2025 Stéfani Faller https://creativecommons.org/licenses/by/4.0
Commented translation of Heisenberg's paper, “On the reinterpretation of kinematic and mechanical relations in quantum theory”
We present the translation of the article published by Werner Heisenberg in 1925, which constitutes a landmark in the development of quantum mechanics. Some introductory comments are presented, followed by the Portuguese version of the text originally written in German.
Copyright (c) 2025 Júlio C. Fabris, Oliver F. Piattella https://creativecommons.org/licenses/by/4.0
The mathematical symphony of the quantum world
This text explores the profound and beautiful interplay between quantum physics and mathematics. We jour ney from the crisis of classical physics at the turn of the 20th century to the elegant, abstract mathematical frameworks that define modern quantum mechanics. We will see how physical problems forced the invention of new mathematics and how mathematical structures, in turn, provided the language to describe the quantum realm. Key figures like Planck, Einstein, Heisenberg, Born, von Neumann, Weyl, and Dirac will guide us,revealing a story where physical intuition and mathematical formalism are inextricably linked.
Copyright (c) 2025 Giuseppe Dito https://creativecommons.org/licenses/by/4.0
Formation and evolution of large-scale structures from the perspective of halo models
The current era of large-scale structure research, driven by projects such as DESI, Euclid, and LSST, demands efficient methods for modeling and interpreting vast datasets. The matter power spectrum, P(k, z), is a central statistical estimator in these efforts, but its modeling on nonlinear scales remains an ongoing challenge in the literature. In this context, halo models provide a powerful approach by associating the distribution of matter with halos of different masses. Widely used in tools such as HALOFIT and HM-CODE, these models play a fundamental role in data analysis and cosmological parameter inference. This article aims to provide an introductory and didactic resource that reviews the essential components of halo models, highlighting their advantages, such as flexibility beyond the standard ΛCDM model, and their impact on galaxy property predictions, observational studies, and theoretical modeling. The review is presented in a clear and accessible manner, aiming to introduce this approach, which will become increasingly indispensable in modern cosmology.
Copyright (c) 2025 Emanuelly Silva, Rafael C. Nunes https://creativecommons.org/licenses/by/4.0
Quantum mechanics was developed in the early 20th century as a computational algorithm to organize and predict the strange results of a wide variety of experiments involving the microscopic world (molecules, atoms, elementary particles), which appeared random but had a predictable probabilistic distribution. Despite its overwhelming success, the conceptual foundations of this algorithm remain unclear and extremely controversial. How can we connect the microscopic world described by quantum mechanics with the macroscopic world of our daily experience? What is the role of observers in this connection? Why don't strange quantum phenomena occur on macroscopic scales? How can we explain the nonlocal nature of quantum phenomena? In this article I will present some attempts to answer these and other basic questions, which constitute different theories with completely different worldviews, commenting on their strengths and weaknesses. We will conclude that quantum theory is still under construction, as there is no consensual formulation. Its development is a fundamental problem in contemporary physics, and in thought in general.
Copyright (c) 2025 Nelson Pinto Neto https://creativecommons.org/licenses/by/4.0
White dwarfs are highly compact stellar remnants resulting from the evolutionary process of stars with masses up to ten times that of our Sun. Their core is composed predominantly of electronically degenerate matter. In an ordinary star, there is a balance between the intrinsic gravitational attraction and the internal pressure generated by the heat and nuclear radiation from its core. In a white dwarf, collapse is prevented by the electron degeneracy pressure, a quantum effect that arises from the statistical properties of fermions through the Pauli exclusion principle. In this article, we present a simple theoretical model for the structure of white dwarfs and discuss some of its applications in astrophysics.
Copyright (c) 2025 Marco Moriconi, Rodrigo Negreiros https://creativecommons.org/licenses/by/4.0
Density functional theory: foundations, challenges, and new horizons in the quantum mechanics of atoms, molecules, and solids
On the centennial of quantum mechanics, this work provides a comprehensive review of the theoretical foundations, current challenges, and emerging frontiers in many-body quantum theory, with particular emphasis on Density Functional Theory (DFT), the GW approximation, and their applications in fields such as astronomy and in novel methodologies grounded in Machine Learning (ML) and evolutionary algorithms. By surveying these diverse applications, from astrophysical systems to artificial intelligence, we underscore the inherently interdisciplinary character of this sixty-year-old framework, which continues to be indispensable for advancing our understanding of the properties of matter and for driving technological innovation.
Copyright (c) 2025 Matheus S. Barbosa, Leonardo Villegas-Lelovsky, Alberto Torres , Alan B. de Oliveira, Amaury de Melo Souza, Breno R. L. Galvao, Alexandre R. Rocha, Mário S. C. Mazzoni, Matheus J. S. Matos https://creativecommons.org/licenses/by/4.0
Quantum effects in curved spaces: from the particle concept to field theory
Quantum field theory is currently the most accurate description of matter, but this framework is the result of a long evolution of the concept of particle in physics. In this article, we trace this development: starting from classical mechanics, where particles are treated as point-like objects; moving to quantum mechanics, where they are described as waves associated with probabilities; and finally arriving at quantum field theory, where particles appear as excitations of fundamental fields. We show that in curved or expanding spacetimes, the definition of a particle is no longer unique: different observers can adopt different vacuum states and consequently identify particles in different ways. We also discuss the role of the quantum vacuum and its connection to the cosmological constant problem, one of the major open questions in contemporary physics. By connecting quantum theory, general relativity, and cosmology, the article addresses both the progress achieved and the conceptual challenges that remain in describing the universe at its most extreme scales.
Copyright (c) 2025 Sandro Dias Pinto Vitenti https://creativecommons.org/licenses/by/4.0
The problem of time in gravitation and cosmology
IIn this outreach review, we discuss key concepts of quantum theory and their application to the construction of a quantum theory of gravitation and cosmology. Of special significance is the problem of time: how can we understand the evolution of a quantum Universe if there is no classical variable that represents an absolute time?
Copyright (c) 2025 Leonardo Chataignier https://creativecommons.org/licenses/by/4.0
Tests of quantum gravity in the laboratory
This work introduces some of the main topics related to recent efforts to conduct experiments that prove the quantum nature of gravity in the laboratory. An overview of the conceptual problems involved will be presented, describing the most well-known theories as well as discussing some of the most relevant approaches for laboratory experiments, such as the Diósi-Penrose decoherence model. Using the formalism of canonical quantization of linearized gravity, it is demonstrated how predictions are beginning to be extracted from the known theories for a regime that is still little explored experimentally. Next, some of the main experimental proposals in the literature are discussed, particularly the possibility of generating entanglement between two massive sources in a state of quantum superposition and the tests involving optomechanical systems. The conclusions list open problems related to traditional methods of gravity quantization in the low-energy regime and discuss the most promising experimental paths to test predictions that could confirm the quantum nature of the gravitational field.
Copyright (c) 2025 Francisco Bento Lustosa https://creativecommons.org/licenses/by/4.0
In 1974, a discovery shook the scientific community. Stephen Hawking showed that, when quantum mechanics is taken into account, black holes are not black but emit thermal radiation, as measured by stationary observers far away from the black hole. Since then, the resulting process of black hole evaporation has sparked a debate that divides physicists to this day: what happens to the information that falls into the black hole? In this article, we will review the process of black hole evaporation, showing in particular that there is nothing paradoxical about the loss of information in the end. We will then examine the alternatives to information loss, highlighting their pros and cons.
Copyright (c) 2025 André G. S. Landulfo https://creativecommons.org/licenses/by/4.0
Quantum effects in gravitation and gravitational analogues
Modern physics reveals that the quantum vacuum, far from being an absolutely empty space, exhibits peculiar properties when analyzed in a curved spacetime, such as in the vicinity of black holes. The interaction between quantum fields and spacetime geometry is formally described by Quantum Field Theory in Curved Spacetimes, which treats gravitational effects as classical manifestations of spacetime curvature, as established by General Relativity. Hawking radiation, for instance, describes how quantum fluctuations near a black hole lead to thermal emission to the exterior, resulting in its gradual evaporation. Another example is the Unruh effect, which predicts that an accelerated observer perceives a thermal bath of radiation in a region where an inertial observer would see only the particle vacuum. However, these phenomena are difficult to detect directly due to the extreme scales involved, which result in thermal emissions of extremely low temperatures. To overcome this limitation, scientists have developed analogue models of gravity. These analogue models are systems (for example, fluid flows and ultracold gases) that reproduce, in the laboratory, conditions equivalent to curved spacetimes. Experiments based on these models allow us to study how spacetime structure influences the quantum behavior of the vacuum, bridging theory and observation and deepening our understanding of the interface between gravity and quantum mechanics.
quantum field theory in curved spacetimes
Copyright (c) 2025 Lucas Tobias de Paula, Murillo Spadin Domingues, Maurício Richartz https://creativecommons.org/licenses/by/4.0
A forgotten Pioneer: Guido Beck and the prediction of gravitational waves
In 1925, the young Austrian physicist Guido Beck obtained the first exact solution to the equations of general relativity that exhibits the phenomenon of energy transport via gravitational waves. Despite its relevance and pioneering character, Beck's work remained unknown to the physics community for decades. Here we present a translation into Portuguese of the original article, written in German, in which Beck presents these results, along with an overview of the early years of his career, when he worked in the field of general relativity.
Copyright (c) 2025 Alexandre Sampaio da Cruz, Rafael Velloso, Antonio Augusto Passos Videira https://creativecommons.org/licenses/by/4.0
The rebirth of general relativity: theses and historiographical perspectives
In this article, we discuss the thesis, common among physicists and historians, that, after three decades of stagnation, there was a “renaissance” of interest in general relativity in the 1950s and 1960s. We present two versions of this thesis: one places the shift in the 1950s, following the first conferences dedicated to general relativity, and the other identifies the shift in the 1960s, due to advancements in astrophysics. We review the main arguments supporting this thesis by physicists and historians, recall some of the criticisms it has received, and analyze the key historical evidence that emerges in this historiographical debate. Finally, we reflect on the validity of this thesis and on the current challenges in research on the history of general relativity.
Copyright (c) 2025 Juliana Correia Ferreira, Juliana Youssef, Thiago Hartz https://creativecommons.org/licenses/by/4.0
From gravity to water: analyzing climate change in Brazil with computational methods
Predicting droughts and floods in climatically dynamic regions requires rigorous analyses that integrate both spatial and temporal information. This study leverages gravitational data from the GRACE missions to examine hydrological variability in Brazil, an area of strategic importance due to its extensive river network and high sensitivity to global climate phenomena such as El Niño and the Pacific Decadal Oscillation. By adopting a computational framework that includes Singular Value Decomposition (SVD), CFAR (peak detection), and DBSCAN (spatial clustering), key variability patterns are identified and highlight regions with elevated hydrological vulnerability, notably Manaus, Mato Grosso, and Minas Gerais.
Copyright (c) 2025 Fabian Trigo https://creativecommons.org/licenses/by/4.0
Official monitoring of Brazil's native vegetation using satellite images: the BiomasBR program and the Prodes, Deter and TerraClass systems
The Brazilian government has three official satellite monitoring systems for monitoring native vegetation loss in its six biomes, designed and executed by the National Institute for Space Research, through the Brazilian Biomes Monitoring Program (BiomasBR): 1) Prodes - Annual Monitoring of Native Vegetation Suppression; 2) Deter - Daily Monitoring of Suppression and Degradation of Native Vegetation; and 3) TerraClass - Systematic Monitoring of Land Cover and Use. This article presents the main characteristics of each of these systems, the most recent results of Brazilian native vegetation monitoring, the main public policies based on BiomasBR, and the role of the program as a tool for achieving goals within international climate agreements.
João Felipe Sobrinho Kneipp Cerqueira Pinto
Copyright (c) 2025 Cláudio Aparecido de Almeida, Letícia Palazzi Perez, Mariane Souza Reis, Vagner Luis Camilotti , Cassiano Gustavo Messias, Erison Carlos dos Santos Monteiro, Taise Farias Pinheiro, João Felipe Sobrinho Kneipp Cerqueira Pinto, Luciana de Souza Soler, Lubia Vinhas, Luis Eduardo Pinheiro Maurano, Marcos Adami, Tatiana Mora Kuplich, Gustavo F. Balué Arcoverde, Igor da Silva Narvaes da Silva Narvaes, Silvana Amaral https://creativecommons.org/licenses/by/4.0
Climate Change and the Challenges Faced by the Amazonia
The Amazon, one of the most biodiverse biomes on the planet, plays a crucial role in global climate regulation and the hydrological cycle of South America. However, climate change and the intensification of human activities, such as deforestation and wildfires, have significantly impacted the region’s ecological stability. This article analyzes the effects of land-use changes on the Amazonian climate, emphasizing the relationship between forest degradation, greenhouse gas emissions, and alterations in precipitation patterns. It also discusses the impacts of atmospheric pollution, including locally and transcontinentally sourced aerosols, which affect the radiative balance and rainfall formation. Given this scenario, the need for strict environmental policies and international cooperation is reinforced to mitigate the effects of climate change and preserve the biome’s resilience. The upcoming COP 2025 in Belém do Pará is highlighted as a strategic opportunity to strengthen global commitments to forest conservation and environmental impact mitigation.
Copyright (c) 2025 Marco Aurélio de Menezes Franco https://creativecommons.org/licenses/by/4.0
The Production of ignorance about science: an analysis of the relationship between propaganda, the climate emergency and information ethics
Despite an apparent consensus on the strategic value of science for society and the material gains that the development of research and technologies brings to industry, culture and power relations, there is an important debate about the influence of external political and economic values on scientific knowledge. Using the conceptual perspective of agnotology, this article analyzes how propaganda campaigns use the information ethics of digital platforms to produce and disseminate doubt and ignorance about scientific knowledge of anthropogenic climate change and its spokespeople. Based on a literature review, we reinforce the warning of astrophysicists, geologists, sociologists and many other scientists about how the idea of a “neutral science” weakens the community and fuels denialism. We observe the main strategies and discourses that combat the consensus on the climate emergency and its relationship with an unsustainable economic model of exploitation of the planet’s resources, pointing out the responsibilities of the oil industry, agribusiness and big tech in this scenario.
Copyright (c) 2025 Carlos Eduardo Barros https://creativecommons.org/licenses/by/4.0
In this article are discussed the main causes suspected to be responsible for the massive extinction of species during the last 600 million years of the Earth’s history. Generally, cosmic catastrophes and volcanism have been invoked as the main reasons. However, in the present days, there is a consensus among experts that these extinction episodes are due to multiple causes, which modify the habitat, in particular the climate, in a short timescale. Consequently, species do not have enough time to adapt themselves to the new environment and disappear. There are indications that we are in the dawn of a new massive extinction that may have severe implications for the surviving of the humanity.
Copyright (c) 2025 José Antônio de Freitas Pacheco https://creativecommons.org/licenses/by/4.0
The historical supernovae, recorded by different observers around the globe for many centuries, may have also been depicted as rock art by Indigenous peoples of the Americas. There are suggestions of the association of petroglyphs and rupestrian art in the northern hemisphere with some of these events. This work aims to present and discuss whether a set of petroglyphs located in the states of Paraíba and Rio Grande do Norte may represent these historical supernovae. Using Stellarium software, the sky patterns at the time of each supernova explosion were simulated and then compared to the figures found. Considering the well-established cultural practices of the Tarairiú peoples, we identified suggestive correspondences between the figures and the supernovae of 185, 1054, and 1572, although the start of a definitive confirmation depends on dating analysis not yet available.
Copyright (c) 2025 Jorge Ernesto Horvath, Bianca Bulhões Martins, Felipe Felipe Sérvulo Maciel Costa, Luiz Carlos Jafelice https://creativecommons.org/licenses/by/4.0
Some reflections on the construction and legitimization of scientific knowledge
The practice of a scientific activity is an issue not frequently addressed and that has a large impact on the future researchers. In general, a series of postulates and beliefs are presented to the students which are far from reality, much more complex and less ideal that the discourse. We discuss these aspects in some detail, introducing the idea of a pyramidal structure of the scientific community, and point out several difficulties for a successful passage to it, dismounting in passing that ideal utopic picture.
Copyright (c) 2025 Jorge Ernesto Horvath https://creativecommons.org/licenses/by/4.0
Human development, which began around 300,000 years ago, has always occurred in parallel with natural climate variations. However, since the Industrial Revolution, human action has intensified the greenhouse effect, raising the average global temperature and altering weather patterns, resulting in severe impacts such as rising temperatures, changes in precipitation patterns and an increase in the frequency of severe weather events such as storms, tornadoes and hurricanes. This article explores the main current climate changes and how they are monitored through the analysis of historical data. In addition, it presents projections from climate models that allow us to anticipate future scenarios, including rising temperatures and changes in precipitation patterns, especially in South America. Finally, the text highlights the importance of concrete actions to mitigate greenhouse gas emissions, responsible for current climate change, using technologies already available. We conclude that, in order to face the climate emergency, it is essential to integrate Brazil’s human and natural resources, combined with scientific knowledge, in order to implement effective solutions to reduce impacts and protect the most vulnerable populations.
Copyright (c) 2025 Amanda Rehbein, Tercio Ambrizzi https://creativecommons.org/licenses/by/4.0
Cosmic Rays and their Connections to Earth's Climate
There is now a consensus among scientists that human contribution to greenhouse gas emissions has caused a significant increase in global temperature over the last century, with simulations indicating an increase of around 5.0°C by 2100. In these models, cloud dynamics contribute the greatest uncertainties. Although the process is based on a relatively well-known chain, from aerosols evolving into condensation nuclei to macroscopic clouds, the role of ionic induction promoted by cosmic rays as a possible intensifier of nucleating processes in the atmosphere remains inconclusive. Recent research carried out at the particle physics laboratory, CLOUD/CERN, despite the difficult task of emulating the atmosphere in the laboratory, has yielded results that motivate its study in a real system, as in the Brazilian project CRE4AT (Cosmic Ray Experiment for Atmosphere).
Copyright (c) 2025 André Massafferri Rodrigues https://creativecommons.org/licenses/by/4.0
The mean life of CO2 in the Earth's atmosphere and the temperature increase over the 2050 horizon
In this work a toy model is presented describing the evolution of the CO2 level in the Earth’s atmosphere. Using present data on the CO2 emission resulting from the human activity and carbon stockage by mechanisms acting in the biosphere, the average lifetime of CO2 in the atmosphere was estimated to be 120 years. If the emission rate behavior observed in the last decades is maintained, our model predicts around 2050 a CO2 concentration of 513 ppm and a temperature increase of +2,6°C above the limit fixed by the Paris agreement.
Copyright (c) 2025 J. A. F. Pacheco https://creativecommons.org/licenses/by/4.0
The Antarctic Climate and the Four Decades of Research in the Brazilian Antarctic Program
Antarctica plays a key role in the planet’s climate dynamics. Its characteristic cold climate is responsible for maintaining temperatures, global climate modulation, sustaining ecosystems and ice-dependent biodiversity. Likewise, the region is significantly impacted by global climate change. Over the past few decades, the Brazilian Antarctic Program has been making efforts to study the region, with several modules and facilities used to collect climatic, atmospheric, and biological data, among others. This paper characterizes the Antarctic climate, its importance in the global context, the impacts of climate change on Antarctica, and the efforts of the Brazilian Antarctic Program to study the polar climate.
Copyright (c) 2025 Dafne Anjos, Cesar Amaral, Anna Donato, Rodrigo Goldenberg-Barbosa, Letícia Eller https://creativecommons.org/licenses/by/4.0
Front-matter with editorial considerations on the present number from Cadernos de Astronomia.
Commented translation of "On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground" from Svante Arrhenius (1896)
Published in 1896 in the Philosophical Magazine and Journal of Science, Arrhenius' scientific paper is a pioneer in the quantitative study of the greenhouse effect, a central theme in the discussion on global warming. As well as being an important historical record, it is interesting to note that this work contains a methodology that paved the way for today's climate models.
Copyright (c) 2025 Matheus Barbosa Rasch, Maria Tereza Weitzel Dias Carneiro Lima https://creativecommons.org/licenses/by/4.0