India approves LIGO, Hanford equipment to be used

India has agreed to establish a Laser Interferometer Gravitational-wave Observatory to be equipped with a detector now stored in boxes at the LIGO at Hanford.

India had first been offered the gravitational wave detection equipment on October 2011.

The Indian Cabinet, led by Prime Minister Shri Narendra Modi, granted in-principle approval for a LIGO in India following the historic announcement last week of the first observation of gravitational waves arriving at the earth.

“The discovery didn’t hurt,” said Fred Raab, head of the LIGO at Hanford.

A very aggressive schedule has been set to have the observatory in India operating in a little more than seven years, Raab said. Researchers in India have been doing a significant amount of work on the project while waiting for a government decision.

The detector that will be used in India is near identical to the one used at the Hanford LIGO and its twin in Louisiana, ensuring it will come quickly up to speed and match the performance of the U.S. detectors. The two U.S. LIGOs made the first observation of gravitational waves on Sept. 14, confirming their existence predicted by Albert Einstein’s general theory of relativity 100 years ago.

Gravitational waves from the violent merger of two black holes 1.3 billion years ago caused one of the 2.5-mile long arms of the Hanford LIGO to stretch an infinitesimal amount and the other to shorten as they passed through the earth.

The same thing happened seven-thousands of a second earlier at the Louisiana LIGO. The observatories can detect a change in the length of the arms smaller than one-ten-thousandth the diameter of a proton.

At one time there was talk of placing the nation’s third LIGO at Hanford, and the uninstalled detector equipment remains there. But it made more sense to find another nation willing to be home to the LIGO to allow triangulation of data. When Australia declined, India, which had scientists already interested in the project, was approached.

The LIGO in India can help make a dramatic improvement in the ability to locate the sources of gravitational waves in the sky, Raab said.

Upgrades are being installed at the Virgo interferometer near Pisa, Italy, and it is expected to come on line next. Japan also is working on an interferometer, which with the Indian LIGO, will make five observatories searching for gravitational waves.

The detection of gravitational waves opens up a new way for scientists to explore universe and answer fundamental questions about it, including answers to questions no one has yet thought to ask.

“Any time you turn on some new type of telescope or microscope, you discover things you couldn’t anticipate,” said David Reitze, executive director of LIGO, in a statement.

Researchers would like to also use other astronomical devices to look for electromagnetic displays from gravitational waves, increasing the knowledge about them. A battery of gamma ray, X-ray, light, infrared, radio and underwater neutrino telescopes could use different technologies to also search for signals from the waves.

But those observatories need to narrow down the area of the sky where they should search for light or other electromagnetic displays, and that can be better pinpointed by interferometers first detecting the waves at multiple locations around the globe.

Raab calculates that if you draw a circle around the Earth with a radius from Earth to the source of the recently detected gravitational waves, it would encompass 5 million galaxies.

The National Science Foundation has paid for most of the U.S. LIGO work, including the detector that eventually will be shipped from Hanford to India, through a program jointly managed by the California Institute of Technology and the Massachusetts Institute of Technology. India will build its observatory and staff it.

Raab and other LIGO scientists already have made many trips to India to work with Indian colleagues at the three leading research institutions there involved in the project.

“Together, we have identified an excellent site for the facilities and have transferred detailed LIGO drawings of the facilities … after adapting them for conditions in India,” Raab said.

This story was originally published February 18, 2016 at 7:14 PM with the headline "India approves LIGO, Hanford equipment to be used."