14 DAY TRIAL // In August 2002, the Laser Interferometer Gravitational-wave Observatory, or LIGO, became operational and started looking for the elusive gravitational waves predicted by Albert Einstein. It collected a massive amount of data, probably including some gravitational waves, however when scientists were put to the daunting task of filtering that data, they realized it was close to impossible. Basically, they cannot say whether they have detected or not an actual gravitational wave.
However, the LIGO project is set to receive a critical upgrade, which will be finished by 2014, when the LIGO instrument will be so sensitive that it will be able to detect a gravitational wave every week or so.
The Theory of General Relativity predicts that gravitational waves are distortions in the fabric of space-time, produced by gravitational interactions between massive objects such as two or more black holes, neutron stars and so on. "With the upgrade, either we'll see a signal or Einstein's General Theory of Relativity will be wrong," said LIGO director Jay Marx from Caltech.
Detecting an exotic phenomenon such as a gravitational wave would allow physicists to observe the universe from a totally different perspective, and even to witness events such as the merging of black holes and the background gravitational ripple produced during the Big Bang event. LIGO consists of two detectors, one in Livingston, Louisiana, and the other at Hanford, Washington, each watching for slight changes in the distance between two fixed mirrors.
The upgrade
LIGO is one of the most sensitive instruments on Earth, maybe even in the whole universe, but as you can see it's not sensitive enough, at least not at this moment and for the given task. The odds of detecting gravitational waves is so small, that it may take several decades before we even get the chance of detecting a single wave.
In order to fix this, the National Science Foundation is planning an upgrade called Advanced LIGO, with a total cost of 205 million US dollars. All the laser systems of the current instrument will be replaced with 180-watt lasers, so that in the end it will be able to detect frequencies with a sensitivity 10 times greater than the current configuration.
This basically translates into detecting gravitational waves which are located ten times farther away from the Earth than the estimated detection distance currently available, thus the searched volume will increase by 1,000 times. "With Advanced LIGO, we think we'll be seeing gravitational waves from sources maybe once a week. Advanced LIGO really opens the door to a new form of astronomy," said Marx.