Equivalence Principle's Test with Improved Accuracy using a Cryogenic Differential Accelerometer Installed on a Pendulum.

We present here a concept for a new experimental test of the Weak Equivalence Principle (WEP) carried out in the gravity field of the Sun. Two test masses of different materials are the central elements of a differential accelerometer with zero baseline. The differential accelerometer is placed on a pendulum, in such a way as to make the common center of mass coincident with the center of mass of the pendulum. Ensuring a very precise centering, such a system should provide a high degree of attenuation of the local seismic noise, which together with an integration time of the order of tens of days would allow verification of the WEP with an accuracy improved by at least an order of magnitude with respect to the state of the art. One of the strengths of this experiment is the know-how acquired from a previous study and technology development (GREAT: General Relativity Accuracy Test) that involved a test of the WEP in the gravity field of the Earth, in free fall inside a co-moving capsule released from a stratospheric balloon. The description of the experiment will be followed by a critical analysis of the challenges associated with its implementation.Astronom

"Galileo Galilei" (GG) a small satellite to test the equivalence principle of Galileo, Newton and Einstein

"Galileo Galilei" (GG) is a small satellite designed to fly in low Earth orbit with the goal of testing the Equivalence Principle-which is at the basis of the General Theory of Relativity-to 1 part in 1017. If successful, it would improve current laboratory results by 4 orders of magnitude. A confirmation would strongly constrain theories; proof of violation is believed to lead to a scientific revolution. The experiment design allows it to be carried out at ambient temperature inside a small 1-axis stabilized satellite (250 kg total mass). GG is under investigation at Phase A-2 level by ASI (Agenzia Spaziale Italiana) at Thales Alenia Space in Torino, while a laboratory prototype (known as GGG) is operational at INFN laboratories in Pisa, supported by INFN (Istituto Nazionale di fisica Nucleare) and ASI. A final study report will be published in 2009

Corrigendum to: The TianQin project: current progress on science and technology

In the originally published version, this manuscript included an error related to indicating the corresponding author within the author list. This has now been corrected online to reflect the fact that author Jun Luo is the corresponding author of the article

Global deformations of the Eurasian plate and variations of the Earth rotation rate

Strain data recorded by two laser interferometer–strainmeters operating in the Baksan (Russia) and Gran Sasso (Italy) underground observatories, and the length-of-day (LOD) data describing the variable rate of the Earth's rotation are used to study the relation between the deformation processes in the lithosphere and the global geodynamics of the Earth over short time intervals. The methods applied are based on analysis of the coherence of the studied processes, and correlation analysis. A significant (90%) correlation is revealed between the local deformation fields at two remote observation stations, which proves the existence of a global (at least on the scale of the Eurasian plate) component in the Earth's deformation field that manifests itself at characteristic time intervals of up to 1–2 months. At the same level of significance, the correlation between the local deformation fields and variations in the rate of the Earth's rotation has also been identified. The found correlations in the tidal low-frequency range are caused by the direct impact of the long-period tidal loading (Mf and Mtm waves) on the lithosphere and the length-of-the-day (LOD). On the contrary, the significant correlation in the non-tidal range is probably linked to irregular perturbations of the continental character, which create a coherent interference in the studied processes. The global mechanism that causes this coherent noise requires further study