This set of articles is the result of an international workshop focused on the various attempts to check the role of General Relativity in Gravity by measurements in space. The book presents all proposals for modification of gravitational theory in one volume.

Observing our Universe and its evolution with ever increasing sensitivity from ground-based or space-borne telescopes is posing great challenges to Fundamental Physics and Astronomy. The remnant cosmic microwave background, as beautifully measured by successive space missions COBE, WMAP, and now PLANCK, provides a unique probe of the very early stages of our Universe. The red-shift of atomic lines in distant galaxies, the dynamics of pulsars, the large scale structure of galaxies, and black holes are a few manifestations of the theory of General Relativity. Yet, today, we understand only 4% of the mass of our Universe, the rest being called dark energy and dark matter, both of unknown origin! A second family of space missions is currently emerging; rather than designing ever more re nedobservationalinstruments,physicistsandengineersseekalsotousethespaceenvironment to perform high-precision tests of the fundamental laws of physics. The technology required for such tests has become available only over the course of the last decades. Clocks of high accuracy are an example. They are based on advances in atomic and laser physics, such as cold atoms, enabling a new generation of highly sensitive quantum sensors for ground and space experiments. Two experiments in space have now tested Einstein's relativity theory: • Several decades ago, Gravity Probe A con rmed the accuracy of the gravitational red-shift ?5 according to general relativity to a level of 7× 10 [R. F. C. Vessot et al. , Test of Relativistic Gravitation with a Space-Borne Hydrogen Maser, Phys. Rev. Lett. 45, 20812084 (1980)].

Covers all aspects in which gravitation plays a role in checking the validity of general relativity Presents all proposals for modification of gravitational theory in one volume Accounts for the possible time dependences of the fundamental constants of physics

Klappentext

This book is the result of an international Workshop on Gravity and the various attempts of checks of the role of General Relativity in Gravity that are based on space data. In its centre stand data on Gravitomagnetism, in particular the results of the Gravity Probe B 'null-experiment' that has measured the Lense-Thirring effect in orbit around the Earth, data derived from observation of astrophysical systems as well as from laser ranging of Earth-orbiting satellites. Tests of possible violations of Newton 's inverse-square law and the equivalence principle are discussed as well as the problem of the constancy of the fundamental physics constants, and constraints on gravitational theory from cosmological observations, Quantum Gravity and Grand Unified Theory. In these respects emphasis is put on the assessment of uncertainty, i.e., to the question as to what extentd high-accuracy measurements are possible in space.

Inhalt
The Confrontation Between General Relativity and Experiment.- From Classical Theory to Quantum Gravity.- Wolfgang Pauli and Modern Physics.- Gravitomagnetism in Physics and Astrophysics.- Gravity Probe B Data Analysis.- Towards a One Percent Measurement of Frame Dragging by Spin with Satellite Laser Ranging to LAGEOS, LAGEOS 2 and LARES and GRACE Gravity Models.- Lense-Thirring Precession in the Astrophysical Context.- New Frontiers at the Interface of General Relativity and Quantum Optics.- The Pioneer Anomaly in the Light of New Data.- The Puzzle of the Flyby Anomaly.- Time-Dependent Nuclear Decay Parameters: New Evidence for New Forces?.- Tests of the Gravitational Inverse Square Law at Short Ranges.- The Equivalence Principle and the Constants of Nature.- Laboratory Tests of the Equivalence Principle at the University of Washington.- Lunar Ranging, Gravitomagnetism, and APOLLO.- Atom-Based Test of the Equivalence Principle.- Testing General Relativity with Atomic Clocks.- Fundamental Constants and Tests of General RelativityTheoretical and Cosmological Considerations.- Testing the Stability of the Fine Structure Constant in the Laboratory.- Constraining Fundamental Constants of Physics with Quasar Absorption Line Systems.- The Role of Dark Matter and Dark Energy in Cosmological Models: Theoretical Overview.- Some Uncomfortable Thoughts on the Nature of Gravity, Cosmology, and the Early Universe.- The Cosmic Microwave Background and Fundamental Physics.- Perspectives on Dark Energy.- An Assessment of the Systematic Uncertainty in Present and Future Tests of the Lense-Thirring Effect with Satellite Laser Ranging.- Misalignment and Resonance Torques and Their Treatment in the GP-B Data Analysis.- Polhode Motion, Trapped Flux, and the GP-B Science DataAnalysis.- The Gravity Probe B Data Analysis Filtering Approach.- GP-B Systematic Error Determination.- Space-Time Metrology for the LISA Gravitational Wave Observatory, and Its Demonstration on LISA Pathfinder.- The Microscope Mission and Its Uncertainty Analysis.- The STEP and GAUGE Missions.- Satellite Test of the Equivalence Principle Uncertainty Analysis.- What Determines the Nature of Gravity? A Phenomenological Approach.