IIHE invited seminar: Advanced Virgo: Probing the dynamics of spacetime
by
Prof.Jo van den Brand(NIKHEF / Vrije Universiteit Amsterdam)
→
Europe/Brussels
Universe
Universe
Description
Albert Einstein's theory of general relativity, published in 1915, gave science a radically new way of understanding how space, time and gravity are related. Gravity is defined as the curvature of spacetime and is caused by the four-momentum of matter and radiation. Einstein predicted that accelerating objects will cause vibrations in the fabric of spacetime itself, so-called gravitational waves. The detection of gravitational waves is the most important single discovery to be made in the physics of gravity. Gravitational waves exist in any theory of gravity that incorporates a dynamical gravitational field, be it a metric theory such as general relativity (or one of its generalizations), or a non-metric theory such as string theory.
Observations of binary pulsars, whose orbital motion evolves in agreement with general relativity, revealed that gravitational radiation must exist. However, no direct observation of gravitational waves has been reported to date. Discovering gravitational waves would confirm once and for all that gravity is a fundamental dynamical phenomenon.
The Virgo detector for gravitational waves consists mainly of a Michelson laser interferometer made of two orthogonal arms being each 3 kilometres long. Virgo is located within the site of EGO, European Gravitational Observatory, based at Cascina, near Pisa on the river Arno plain. Virgo scientists, in collaboration with LIGO in the USA and GEO in Germany, have developed advanced techniques in the field of high power ultra-stable lasers, high reflectivity mirrors, seismic isolation and position and alignment control. In 2015 these collaborations with turn on their advanced instruments in their quest for first detection of gravitational wave events.