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A Relatividade Geral é a teoria atual que melhor descreve os fenômenos gravitacionais, fornecendo a base para a astrofísica e a cosmologia modernas. Além disso, algumas de suas previsões, como a possibilidade de existência de buracos negros, ocupam um lugar de destaque na cultura e no imaginário populares. No entanto, a complexidade matemática da teoria frequentemente dificulta sua inserção efetiva tanto a nível de ensino médio, quanto a nível superior, na formação de docentes em Física. Neste trabalho, propomos o estudo de órbitas relativísticas como uma possível porta de entrada para discussões sobre buracos negros e outros tópicos em Relatividade Geral. Como forma de apoiar esta inserção, apresentamos aqui dois simuladores de órbitas relativísticas que desenvolvemos para esse propósito. O primeiro, que se baseia na análise da energia potencial efetiva associada ao problema, foi pensado como ferramenta para disciplinas de graduação; o segundo, que exige entradas com significado mais intuitivo, pode servir de apoio a atividades a nível de ensino médio. Após apresentar o problema em questão e o funcionamento dos simuladores, discutimos algumas sugestões de uso em sequências didáticas potencialmente significativas.

General Relativity is the current theory that best describes gravitational phenomena, providing the basis for modern astrophysics and cosmology. Furthermore, some of its predictions, such as the possibility of the existence of black holes, occupy a prominent spot in popular culture and imagination. However, the theory's mathematical complexity often makes it difficult to effectively insert it both at secondary and undegraduate levels. In this work, we propose the study of relativistic orbits as a possible gateway to discussions about black holes and other topics in General Relativity. As a way of supporting this insertion, we present here two simulators of relativistic orbits we developed for this purpose. The first, which is based on the analysis of the effective potential energy associated with the problem, was designed as a tool for undergraduate courses; the second, which requires input with a more intuitive meaning, can support activities at high school level. After discussing the problem in question and the usage of the simulators, we discuss some suggestions for its use in potentially significant didactic sequences. [ABSTRACT FROM AUTHOR]

En este estudio se presenta una simulación realizada en python como herramienta didáctica para la enseñanza de la mecánica celeste. El programa que hace la simulación se diseñó para que los estudiantes de cursos introductorios de astronomía visualicen las posibles trayectorias y comprendan las características principales de transferencias orbitales usando como ejemplo el viaje de una nave espacial de la Tierra a Marte y a Júpiter. Se encuentra que el programa también puede utilizarse para determinar las características principales de las órbitas planetarias y relacionar los parámetros de las elipses con la energía y el momentum angular de los planetas, y en general con las leyes de Kepler.

Los CubeSat son pequeños satélites que, debido a las restricciones propias de sus dimensiones, tienen como única fuente de energía celdas foto-voltaicas sobre su superficie. El propósito de este artículo es estimar la cantidad máxima de potencia que puede obtenerse de estas celdas solares, de manera que sea posible realizar un balance de energía cuando se diseñan misiones espaciales con este tipo de satélites. En el escenario analizado, un CubeSat de 10cm x 10cm x 10cm (1U) tiene una cara siempre orientada hacia la Tierra. Se consideran las pérdidas por el coseno del ángulo y la variación de la temperatura debido a la órbita del satélite. Para la estimación se usa un modelo matemático de las celdas solares, con el cual se calcula el punto de máxima potencia según el ángulo de incidencia de la radiación solar y la temperatura sobre una órbita baja alrededor de la Tierra. Los resultados muestran la variación de la potencia eléctrica máxima suministrada por los paneles sobre la porción iluminada de la órbita, sin considerar el albedo de la Tierra. Además de la potencia, se estiman las curvas corriente-voltaje para diferentes ubicaciones sobre la órbita del CubeSat.

El artículo no presenta resumen.

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The fundamental properties of the Ellis wormholes are reviewed. Using the Hamilton-Jacobi formalism, we have derived the effective potentials and the orbit equation for a particle around a wormhole in both Ellis and Morris-Thorne geometries. Finally, we apply the equation obtained in the Morris-Thorne case for a Schwarzschild wormhole.

Apresenta-se aqui uma tradução da demonstração original de um teorema que se deve a J. Bertrand e que diz respeito às leis de atração que admitem órbitas fechadas e limitadas para condições iniciais arbitrariamente escolhidas.

Extraocular muscles are important references in strabismus surgery and in placement of intraorbital devices. We analyzed extraocular muscles morphometry and possible anatomical variances of 20 orbits. We report the length, width, and points of insertion of the extraocular muscles. No anatomical variations in length, width and points of insertion were found. With regard to the rectus muscles, it was found that the superior rectus and lateral rectus are the longest muscles and that the width difference between the superior and inferior rectus is greater than that between the medial and lateral rectus and that the point of insertion of the rectus muscles has a variable morphology. The superior oblique muscle was smaller in caliber than the inferior oblique, as consistent with previous anatomical studies. Knowledge of the detailed morphology of extraocular muscles is fundamental in strabismus surgery and represents a key factor for the innovation of surgical techniques and orbital procedures. [ABSTRACT FROM AUTHOR]

It has planned, designed and elaborated a code on Java that allows to use observations of the position in the time of an object to determine its orbital elements. An interfaces friendly graph, allows to the user to introduce the right ascension, the declination and the time in which the observations are realized and the calculation computational will provide the orbital elements of the observed object. This tool computational will be implemented in line on the Internet net in order that it is useful in the study and analysis of the observations of the solar system. [ABSTRACT FROM AUTHOR]

Copyright of Latin-American Journal of Physics Education is the property of Latin-American Physics Education Network and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ginecología y Obstetricia de México is the property of Federacion Mexicana de Ginecologia y Obstetricia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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