* Astronomy

The Laser Interferometer Gravitational-Wave Observatory (LIGO) has reached its target detection sensitivity, but the goal of finding the elusive phenomena known as gravity waves remains as elusive as ever.

The two facilities, one in Hanford, Washington, and the other in Livingston, Louisiana, began a planned one-year continuous operation – the fifth and longest duration so far – last November. The instruments are able to resolve sudden distortions in space-time as small as 10-18 meter, or one-thousandth the diameter of a proton. But even such sensitivity is not sufficient to catch most cosmological events that could cause gravity waves.

"So far, there has been no direct detection" - Nergis Mavalvala, LIGO team member at MIT.

That should change with the installation of LIGO's next generation of instruments. Where the current configuration can detect only the "brightest" of events, such as the head-on collision of two super massive black holes, the Advanced LIGO package – funding for which is scheduled to be added to the National Science Foundation's budget in fiscal year 2008 – is expected to produce a tenfold improvement in sensitivity.

"The increased sensitivity is firmly set by the astrophysics that we know today" - Nergis Mavalvala.

The Advanced LIGO should improve the chances of gravity-wave detection by a factor of 1,000. This enhanced sensitivity will allow LIGO to detect the space-time implications of cosmic events such as the collisions of smaller black holes, or the absorption by black holes of neutron stars, events estimated to occur somewhere in the universe as often as once per day.
In particular, the team wants to observe a black-hole collision.

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