MG11 
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RELATIVISTIC ASTROMETRY WITH GAIA: ADVANCIES IN THE RAMOD PROJECT

Aim of the RAMOD project is to solve the general relativistic ray-tracing problem in the gravitational field of the Solar System to the accuracy of a micro-arcsecond in the measurements of angles. The project consists in the construction of a family of models with increasing complexity and accuracy each one acting as test bed for the more advanced ones. The models are operated by numerical codes in a multimodular structure which allows one to activate specific functions according to the need. Here we discuss the latest contribution to the model structure consisting in a new modulus conceived to analyze the error budjet and solve the condition equations.

NAKED SINGULARITIES, TIME MACHINES AND IMPULSIVE EVENTS

If a curvature singularity is globally naked then the space-time may be causally future ill-behaved admitting closed time-like or null curves which extend to asymptotic distances. This generates a Cosmic Time Machine. Here the conjecture that a Cosmic Time Machine gives rise to an impulsive event is considered in more details.