The Advanced Laser Interferometer Gravitational Wave Observatory project (LIGO) was dedicated on May 19 in a move that could revolutionize the way astronomy is conducted. The National Science Foundation helped dedicate the facility, located in Richland, Wash.
Astronomers once used visual observations alone to study the universe. Later, they learned to separate light into a spectrum of colors to determine the chemical composition of distant bodies. This advance was followed by radio astronomy and X-ray astronomy, each of which examines objects in space in wavelengths unseen by the human eye. By examining targets in different wavelengths of light, it is possible to observe various phenomena. Gravitational astronomy could represent the newest means of carrying out astronomical observations.
Gravity waves, first proposed by Albert Einstein in 1916, are ripples in the fabric of spacetime. They are produced by masses experiencing acceleration in much the same way as accelerating electrons create radio waves. These waves could reveal information about the ultimate nature of gravity as well as the events creating the gravitational ripples. These have never been observed directly by astronomers, and such detectors would need to be exceptionally sensitive.
LIGO is comprised of two L-shaped detectors known as interferometers that are located in Hanford, Wash., and Livingston, La. Inside each facility, a laser beam is split into two paths that travel along both sides of the "L," bouncing off precisely designed mirrors. If gravitational waves exist, Einstein's General Theory of Relativity predicts the length of each path will vary slightly.
LIGO was already capable of detecting changes in the light path 1,000 times smaller than a proton. The latest updates to the LIGO network will increase sensitivity of the detectors by tenfold. Such an advance would increase the number of targets from which gravitational waves might be detected by 1,000 times.
"Advanced LIGO represents a critically important step forward in our continuing effort to understand the extraordinary mysteries of our universe. It gives scientists a highly sophisticated instrument for detecting gravitational waves, which we believe carry with them information about their dynamic origins and about the nature of gravity that cannot be obtained by conventional astronomical tools," said France A. Córdova, director of the NSF.
Cardiff University astronomers, along with colleagues from other institutions, will use a powerful supercomputer to analyze the data collected.
"The operation of Advanced LIGO will herald the beginning of gravitational wave astronomy. We will make use of the Cardiff University supercomputer to search through the detector data to identify the telltale signs of a gravitational wave signal," said Stephen Fairhurst of Cardiff University's School of Physics and Astronomy.
A binary pulsar system, consisting of a pair of neutron stars, exhibit telltale signs of being influenced by gravity waves. Neutron stars are so dense that a thimbleful of their material weighs more than Mount Everest. Due to evidence seen in this compact, massive system, astrophysicists are relatively sure that gravitational waves are a fundamental characteristic of spacetime.
The upgraded detectors will go online later in 2015.