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Orfeu Bertolami
Orfeu Bertolami ( São Paulo, Brazil, 1959) is a theoretical physicist who works in problems of astrophysics, cosmology, general relativity and quantum gravity. He worked at Instituto Superior Técnico in Lisbon, Portugal from 1991 to 2010. He is currently professor at Departamento de Física e Astronomia of the Faculdade de Ciências da Universidade do Porto. He is the author of a book to raise the awareness of the public on science about the history of ideas in astronomy, cosmology and theories of gravity (in Portuguese) and of a technical text on the aspects of gravity and propulsion in space published by the European Space Agency: * ''O Livro das Escolhas Cósmicas'', Editora Gradiva 2006 * ''Gravity Control and Possible Influence on Space Propulsion: A Scientific Study'', European Space Agency 2002 In particular, Bertolami studiebaryogengesis thcosmological constant problemand its connection with thequivalence principle thgeneralized Chaplygin gas modelof unifica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Ideas
Intellectual history (also the history of ideas) is the study of the history of human thought and of intellectuals, people who conceptualize, discuss, write about, and concern themselves with ideas. The investigative premise of intellectual history is that ideas do not develop in isolation from the thinkers who conceptualize and apply those ideas; thus the intellectual historian studies ideas in two contexts: (i) as abstract propositions for critical application; and (ii) in concrete terms of culture, life, and history. As a field of intellectual enquiry, the history of ideas emerged from the European disciplines of '' Kulturgeschichte'' (Cultural History) and ''Geistesgeschichte'' (Intellectual History) from which historians might develop a global intellectual history that shows the parallels and the interrelations in the history of critical thinking in every society. Likewise, the history of reading, and the history of the book, about the material aspects of book production (des ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jewish Brazilian Writers
Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The people of the Kingdom of Israel and the ethnic and religious group known as the Jewish people that descended from them have been subjected to a number of forced migrations in their history" and Hebrews of historical Israel and Judah. Jewish ethnicity, nationhood, and religion are strongly interrelated, "Historically, the religious and ethnic dimensions of Jewish identity have been closely interwoven. In fact, so closely bound are they, that the traditional Jewish lexicon hardly distinguishes between the two concepts. Jewish religious practice, by definition, was observed exclusively by the Jewish people, and notions of Jewish peoplehood, nation, and community were suffused with faith in the Jewish God, the practice of Jewish (religious) l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmologists
Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description of the largest-scale structures and dynamics of the universe and allows study of fundamental questions about its origin, structure, evolution, and ultimate fate.For an overview, see Cosmology as a science originated with the Copernican principle, which implies that celestial bodies obey identical physical laws to those on Earth, and Newtonian mechanics, which first allowed those physical laws to be understood. Physical cosmology, as it is now understood, began with the development in 1915 of Albert Einstein's general theory of relativity, followed by major observational discoveries in the 1920s: first, Edwin Hubble discovered that the universe contains a huge number of external galaxies beyond the Milky Way; then, work by Vesto Slipher and others showed that the universe is expanding. These advances made it possible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brazilian Physicists
Brazilian commonly refers to: * Something of, from or relating to Brazil * Brazilian Portuguese, the dialect of the Portuguese language used mostly in Brazil * Brazilians, the people (citizens) of Brazil, or of Brazilian descent Brazilian may also refer to: Sports * Brazilian football, see football in Brazil * Brazilian jiu-jitsu, a martial art and combat sport system *''The Brazilians'', a nickname for South African football association club Mamelodi Sundowns F.C. due to their soccer kits which resembles that of the Brazilian national team Other uses * Brazilian waxing, a style of Bikini waxing * Brazilian culture, describing the Culture of Brazil * "The Brazilian "The Brazilian" is an instrumental piece by the English band Genesis that concludes their 1986 album '' Invisible Touch''. The song features experimental sounds and effects. The band wrote two instrumental pieces for the album, this and "Do the N ...", a 1986 instrumental by Genesis * Brazilian barbecue, known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contributors To Physical Cosmology
This is a list of people who have made noteworthy contributions to cosmology (the study of the history and large-scale structure of the universe) and their cosmological achievements A * Tom Abel (1970–) studied primordial star formation * Roberto Abraham (1965–) studied the shapes of early galaxies * Andreas Albrecht studied the formation of the early universe, cosmic structure, and dark energy * Hannes Alfvén (1908–1995) theorized that galactic magnetic fields could be generated by plasma currents * Ralph A. Alpher (1921–2007) argued that observed proportions of hydrogen and helium in the universe could be explained by the big bang model, predicted cosmic background radiation * Aristarchus of Samos (310–230 BC) early proponent of heliocentrism * Aristotle (circa 384–322 BC) posited a geocentric cosmology that was widely accepted for many centuries * Aryabhata (476–550) described a geocentric model with slow and fast epicycles B * Ja'far ibn Muhammad Ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pioneer Anomaly
The Pioneer anomaly, or Pioneer effect, was the observed deviation from predicted accelerations of the ''Pioneer 10'' and ''Pioneer 11'' spacecraft after they passed about on their trajectories out of the Solar System. The apparent anomaly was a matter of much interest for many years but has been subsequently explained by anisotropic radiation pressure caused by the spacecraft's heat loss. Both ''Pioneer'' spacecraft are escaping the Solar System but are slowing under the influence of the Sun's gravity. Upon very close examination of navigational data, the spacecraft were found to be slowing slightly more than expected. The effect is an extremely small acceleration towards the Sun, of , which is equivalent to a reduction of the outbound velocity by 1 km/h over a period of ten years. The two spacecraft were launched in 1972 and 1973. The anomalous acceleration was first noticed as early as 1980 but not seriously investigated until 1994. The last communication with either spa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modified Models Of Gravity
Modified may refer to: * ''Modified'' (album), the second full-length album by Save Ferris *Modified racing, or "Modifieds", an American automobile racing genre See also * Modification (other) Modification may refer to: * Modifications of school work for students with special educational needs * Modifications (genetics), changes in appearance arising from changes in the environment * Posttranslational modifications, changes to prote ... * Modifier (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotation Curves Of Galaxies
Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional object has an infinite number of possible central axes and rotational directions. If the rotation axis passes internally through the body's own center of mass, then the body is said to be ''autorotating'' or ''spinning'', and the surface intersection of the axis can be called a '' pole''. A rotation around a completely external axis, e.g. the planet Earth around the Sun, is called ''revolving'' or '' orbiting'', typically when it is produced by gravity, and the ends of the rotation axis can be called the '' orbital poles''. Mathematics Mathematically, a rotation is a rigid body movement which, unlike a translation, keeps a point fixed. This definition applies to rotations within both two and three dimensions (in a plane and in s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Matter
Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not absorb, reflect, or emit electromagnetic radiation and is, therefore, difficult to detect. Various astrophysical observationsincluding gravitational effects which cannot be explained by currently accepted theories of gravity unless more matter is present than can be seenimply dark matter's presence. For this reason, most experts think that dark matter is abundant in the universe and has had a strong influence on its structure and evolution. The primary evidence for dark matter comes from calculations showing that many galaxies would behave quite differently if they did not contain a large amount of unseen matter. Some galaxies would not have formed at all and others would not move as they currently do. Other lines of evidence include observa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmic Acceleration
Observations show that the expansion of the universe is accelerating, such that the velocity at which a distant galaxy recedes from the observer is continuously increasing with time. The accelerated expansion of the universe was discovered during 1998 by two independent projects, the Supernova Cosmology Project and the High-Z Supernova Search Team, which both used distant type Ia supernovae to measure the acceleration. The idea was that as type Ia supernovae have almost the same intrinsic brightness (a standard candle), and since objects that are further away appear dimmer, we can use the observed brightness of these supernovae to measure the distance to them. The distance can then be compared to the supernovae's cosmological redshift, which measures how much the universe has expanded since the supernova occurred; the Hubble law established that the further an object is from us, the faster it is receding. The unexpected result was that objects in the universe are moving away from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Energy
In physical cosmology and astronomy, dark energy is an unknown form of energy that affects the universe on the largest scales. The first observational evidence for its existence came from measurements of supernovas, which showed that the universe does not expand at a constant rate; rather, the universe's expansion is accelerating. Understanding the universe's evolution requires knowledge of its starting conditions and composition. Before these observations, scientists thought that all forms of matter and energy in the universe would only cause the expansion to slow down over time. Measurements of the cosmic microwave background (CMB) suggest the universe began in a hot Big Bang, from which general relativity explains its evolution and the subsequent large-scale motion. Without introducing a new form of energy, there was no way to explain how scientists could measure an accelerating universe. Since the 1990s, dark energy has been the most accepted premise to account for the acce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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