MG11 |
Participant |
De Felice, Fernando | |
Institution |
Department of Physics The University of Padova - Via Marzolo, 8 - Padova - - ITALY | |
Session |
Talk |
Abstract |
PT2 |
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. |
GT5 |
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. |