Testing gravitational physics with satellite laser ranging
Abstract
Laser ranging, both Lunar (LLR) and Satellite Laser Ranging (SLR), is one of the most accurate techniques to test gravitational physics and Einstein's theory of General Relativity. Lunar Laser Ranging has provided very accurate tests of both the strong equivalence principle, at the foundations of General Relativity, and of the weak equivalence principle, at the basis of any metric theory of gravity; it has provided strong limits to the values of the socalled PPN (Parametrized PostNewtonian) parameters, that are used to test the postNewtonian limit of General Relativity, strong limits to conceivable deviations to the inverse square law for very weak gravity and accurate measurements of the geodetic precession, an effect predicted by General Relativity. Satellite laser ranging has provided strong limits to deviations to the inverse square gravity law, at a different range with respect to LLR, and in particular has given the first direct test of the gravitomagnetic field by measuring the gravitomagnetic shift of the node of a satellite, a framedragging effect also called LenseThirring effect. Here, after an introduction to gravitomagnetism and framedragging, we describe the latest results in measuring the LenseThirring effect using the LAGEOS satellites and the latest gravity field models obtained by the space mission GRACE. Finally, we describe an update of the LARES (LAser RElativity Satellite) mission. LARES is planned for launch in 2011 to further improve the accuracy in the measurement of framedragging.
 Publication:

European Physical Journal Plus
 Pub Date:
 August 2011
 DOI:
 10.1140/epjp/i2011110722
 Bibcode:
 2011EPJP..126...72C