Razmišljanja o kopernikanskem mnenju

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Dialog o dveh velikih sistemih sveta

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OPTIC-04

Se denomina telescopio (del griego τηλε 'lejos' y σκοπέω, 'observar') al instrumento óptico que permite ver objetos lejanos con mucho más detalle que a simple vista. Se presenta un telescopio astronómico refractor de bronce o latón y hierro, de dimensión media, con montura ecuatorial y equilibrado. Posee ocular desmontable, buscador y una barra de alza para apuntar en altura hacia el astro observado. Muestra soporte o trípode de apoyo de tubo de hierro pesado y tornillos. Todas sus piezas son las originales. Materiales: bronce, latón y hierro.Tamaño(altoxlargoxancho): 93x96x27 cmSu invención no está clara, generalmente, se le atribuye a Hans Lippershey, un fabricante de lentes alemán, aunque recientes investigaciones atribuyen la autoría a un gerundense llamado Juan Roget en 1590. Galileo Galilei, al recibir noticias de este invento, decidió diseñar y construir uno y utilizarlo para la astronomía. Destaca la observación, el 7 de enero de 1610, de cuatro de las lunas de Júpiter girando en torno a ese planeta y obtuvo pruebas de que la Tierra orbitaba en torno al Sol. Desde aquel momento, los avances en este instrumento han sido muy grandes como mejores lentes y sistemas avanzados de posicionamiento

Strong quantum violation of the gravitational weak equivalence principle by a non-Gaussian wave-packet

The weak equivalence principle of gravity is examined at the quantum level in two ways. First, the position detection probabilities of particles described by a non-Gaussian wave-packet projected upwards against gravity around the classical turning point and also around the point of initial projection are calculated. These probabilities exhibit mass-dependence at both these points, thereby reflecting the quantum violation of the weak equivalence principle. Secondly, the mean arrival time of freely falling particles is calculated using the quantum probability current, which also turns out to be mass dependent. Such a mass-dependence is shown to be enhanced by increasing the non-Gaussianity parameter of the wave packet, thus signifying a stronger violation of the weak equivalence principle through a greater departure from Gaussianity of the initial wave packet. The mass-dependence of both the position detection probabilities and the mean arrival time vanish in the limit of large mass. Thus, compatibility between the weak equivalence principle and quantum mechanics is recovered in the macroscopic limit of the latter. A selection of Bohm trajectories is exhibited to illustrate these features in the free fall case.Comment: 11 pages, 7 figure

Science, Art and Geometrical Imagination

From the geocentric, closed world model of Antiquity to the wraparound universe models of relativistic cosmology, the parallel history of space representations in science and art illustrates the fundamental role of geometric imagination in innovative findings. Through the analysis of works of various artists and scientists like Plato, Durer, Kepler, Escher, Grisey or the present author, it is shown how the process of creation in science and in the arts rests on aesthetical principles such as symmetry, regular polyhedra, laws of harmonic proportion, tessellations, group theory, etc., as well as beauty, conciseness and emotional approach of the world.Comment: 22 pages, 28 figures, invited talk at the IAU Symposium 260 "The Role of Astronomy in Society and Culture", UNESCO, 19-23 January 2009, Paris, Proceedings to be publishe

Discorso particolare intorno all'unisono

Vincenzo Galilei was among the first music theorists to advocate for a new system of tuning based on performance, instead of the mathematical principles of music set fourth by Pythagoras. Pythagorean music theory bases pitch on the mathematical proportions of dividing a string. Vincenzo's primary problem with this system is that, although it is great for the mathematician and the music theorist, it is impractical for the performer. All music based on this particular system of tuning would inevitably sound out of tune and unpleasant. In this learning leaflet learn about the tuning systems in the late-Renaissance period

Statistical physics of fracture and earthquakes

Manifestations of emergent properties in stressed disordered materials are often the result of an interplay of strong perturbations in the stress field around defects. The collective response of a long-ranged correlated multi-component system is an ideal playing field for statistical physics. Hence, many aspects of such collective responses in widely spread length and energy scales can be addressed by tools of statistical physics. In this theme issue some of these aspects are treated from various angles of experiments, simulations and analytical methods, and connected together by their common base of complex-system dynamics