1,721,043 research outputs found
LARES: a New Laser-Ranged Satellite for Fundamental Physics and General Relativity
No full textIn this paper it is described a new space experiment, using a laser-ranged satellite called LARES, for high precision tests of Einstein's theory of general relativity and for other basic measurements in fundamental physics, geodesy and geodynamics.
Laser-ranged satellites are orbiting spherical objects with embedded on their surface passive devices basically made of glass. These devices are called Cube Corner Retroreflectors (CCRs) and have the property of reflecting back toward the same direction the impinging light. The attitude of the satellite is not a strict requirement since independently of the orientation, there is always at least one CCR visible from one or more ground stations on Earth. Since the satel-lite is totally passive, the orbit determination is performed by measuring the total time of flight of laser pulses sent by the laser-ranging stations located in different regions of the world.
Today, the gravitational theory of Einstein's, i. e. general relativity, is an important field of work in relation to space research and navigation in the solar system. From the basic general relativistic corrections included to describe the motion of the Global Positioning Satellites to the required level of accuracy, to the need of general relativistic corrections in the techniques of Very Long Baseline Interferometry and Satellite Laser Ranging. On the other hand, the attempts to unify the four fundamental interactions of nature, to find a theory which reconciles the gravitational interaction described by general relativity (a classical theory) and quantum mechanics, and other conceptual argumentations have produced various conceivable gravita-tional theories that have to be experimentally tested. Therefore, it is crucial to measure and to test accurately each prediction of general relativity versus alternative theories of gravitation. Several tests and measurements in general relativity and fundamental physics, and also in geodesy and geodynamics, will be performed using LARES (LAser RElativity Satellite)
Testing general relativity with a high-density satellite
Full text linkThe Laser Relativity Satellite is built from a specifically chosen, dense tungsten alloy and is covered with laser retroreflectors to test general relativity and fundamental physics
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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