By Pacôme Delva (Observatoire de Paris) et Guillaumle Lion (IPGP Géodésie)
Thursday the 21st of novembre 2019 at 11H00 – Salle 310 – IPGP – ÎLOT CUVIER
The measurement of time has always been closely related to the
observation of the Earth. Today, the best optical atomic frequency
standards can reach inacurracies around 10?18 in terms of relative
frequency. Because time flow is affected by gravity, it means optical
clock comparisons could measure gravity potential differences with an
accuracy of 0.1 m2/s2, which is equivalent to 1-cm in height difference,
opening new fields of fundamental and applied research.
In this talk, we will introduce what is an optical atomic clock and
how remote clock comparisons could help us improve the knowledge of the
Earth’s gravity field. Then, we will present various applications that
could bring the exploitation of clock measurements in geodesy:
determination of the geopotential with high spatial resolution, vertical
reference system, and we will discuss the possible applications
associated to the geodynamic processes related to mass transfers.