LIGO to get major upgrade in sensitivity

[MeteorWayne]

<p>http://www.space.com/businesstechnology/080409-tw-ligo-advanced.html</p><p>&nbsp;</p><p class="MsoNormal"><span style="font-size:10pt;font-family:Arial">A $205 million upgrade will allow a laser-wielding observatory to monitor tens of thousands of galaxies for mysterious gravitational waves.</span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:Arial">Leading investigators are confident that the Advanced LIGO (Laser Interferometer Gravitational-wave Observatories) Project will be able for the first time to detect gravitational waves from neutron stars and black holes, as predicted by Einstein's theory of general relativity.</span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:Arial">"With the limited LIGO range at time, it wasn't guaranteed detection," said </span><span style="font-size:10pt;font-family:Arial">Albert Lazzarini</span><span style="font-size:10pt;font-family:Arial">, deputy director of LIGO at the California Institute of Technology. "With Advanced LIGO, it'd be very surprising from a relativity perspective if we didn't observe anything."</span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:Arial">Gravitational waves are ripples thought to occur in the fabric of space-time that result from interstellar collisions, explosions, or the dramatic movement of large and extremely dense objects such as neutron stars. Those ripples can then pass through the space-time that Earth occupies, causing a slight distortion which Advanced LIGO is meant to pick up on.</span></p><p class="MsoNormal"><strong><span style="font-size:10pt;font-family:Arial">How it works</span></strong></p><p class="MsoNormal"><span style="font-size:10pt;font-family:Arial">LIGO tries to detect gravitational waves using highly precise lasers to measure the time it takes light to travel between mirrors. Two sets of facing mirrors sit at a 90 degree angle, forming something like an "L" shape that meets at a corner. A laser beam is shot through an "L" shaped splitter at the corner, which splits the beam into two beams that strike each set of mirrors.</span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:Arial">The laser interferometer measures how long the laser light bounces back and forth between the mirrors on the "L" legs before returning to a light detector at the "L" corner. They should theoretically return to the light detector at the same time because the mirror legs are identical distances &ndash; unless a passing gravitational wave distorts the local space-time fabric and changes the distance.</span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:Arial">But the observatory, operational since 2002, has yet to detect the elusive, still-theoretical waves. </span></p><p style="text-indent:0in" class="MsoNormal"><span style="font-size:10pt;font-family:Arial">Scientists foresaw that advances in laser technology and mirrors would allow for even greater sensitivity when LIGO was first proposed, and so the Advanced LIGO Project became a natural upgrade for the observatory. The National Science Foundation recently approved the proposal to upgrade LIGO over the next seven years, starting with $32.75 million in 2008.</span></p><p class="MsoNormal"><span style="font-size:10pt;font-family:Arial">"The first several hours of observation with new instruments will equal almost the first year of observation with LIGO's current instruments," Lazzarini said. "We can probe something like several hundred galaxies out to the Virgo cluster [59 million light-years away] with LIGO, but increase that by a factor of one thousand and you go to the cosmological regime of measuring many tens of thousands of galaxies."</span></p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>