For more than a decade, scientists have been able to detect gravitational waves- ripples in space-time that help us understand the universe's evolution and the most violent events in the cosmos-using the US National Science Foundation's Laser Interferometer Gravitational-wave Observatory (LIGO) , managed by Caltech and MIT. Now, a new ear on the cosmos will be joining a global network of gravitational-wave detectors that also includes observatories in Italy ( Virgo ) and Japan ( KAGRA ). LIGO-India broke ground on April 23, 2026, at Aundha in the Hingoli district of Maharashtra, located in the western peninsular region of India.
"This has been 20 years in the making, and we are finally making it happen," says Rana Adhikari, professor of physics at Caltech and a longtime member of the LIGO collaboration. "The clock has turned on, so it's time for us to really get it going."
Funded by the Indian government, the new LIGO-India observatory will sit on a 174-acre site selected for its low seismic noise to reduce vibrations that could interfere with the detection of gravitational-wave signals. It will be identical in design to the LIGO detectors in Hanford, Washington, and Livingston, Louisiana, and will house an Advanced LIGO laser interferometer with two 4-kilometer-long arms. Caltech and the LIGO Laboratory are providing key interferometer components and technical designs, along with training and support.
LIGO ushered in the field of gravitational-wave astronomy in 2015 when it made the first-ever direct detection of gravitational waves, a discovery that subsequently earned three of its founders the Nobel Prize in Physics in 2017 . In subsequent years, Virgo and KAGRA came online and joined the LIGO Scientific Collaboration , giving researchers from around the world more opportunities to share data, collaborate on observation runs, and advance the field of gravitational-wave science. LIGO-India extends the global network of detectors into a true worldwide array.
"By making a major investment in constructing the LIGO-India Observatory, India is not only enhancing our ability to detect, locate, and identify high energy cosmic collisions, it is positioning itself as a world leader in one of the most exciting frontiers of astrophysics," says David Reitze, the executive director of LIGO and a research professor of physics at Caltech.
Researchers have made major advances in technology since LIGO began observations, so although LIGO-India is a copy of the first-generation detectors in most ways, Adhikari says the team expects the new observatory to be more sensitive and more modern than the original instruments. Advances in artificial intelligence have enhanced LIGO's capabilities and boosted its performance to detect a larger variety of blacks holes and black hole mergers while helping automate some of the operations that used to be manual.
LIGO researchers have also made recent advances in quantum technology, including a technique called "squeezing" that allows them to measure undulations in space-time across the entire range of gravitational frequencies detected by LIGO.
"A lot of technology has improved in the last decade, so the stuff that we'll install will be more advanced than what we have in the US detectors right now," Adhikari says. "It'll be fresh off the block."
As of early 2026, the global detector network has confirmed more than 200 gravitational-wave detections across four completed observing runs, with hundreds of additional candidates from the most recent run under analysis. Sources include mergers of black holes, neutron stars, and mixed black hole-neutron star systems. Adding LIGO-India to the network is predicted to enable incredible scientific gains in physics, astronomy, and more.
For example, by having a counterpart to the US observatories across the globe, LIGO-India will allow researchers to gather data from another angle, making it easier to triangulate the location of a given cosmic event. In addition, LIGO-India's unique orientation will help resolve a current challenge involving polarization, a measurement used to map magnetic fields around black holes, among other uses. Polarization is a fundamental property of gravitational waves and represents which direction the oscillatory component of a gravitational wave is oriented with respect to the wave's general direction of travel. Being able to view colliding black holes-the source of most of the gravitational waves detected-from a different position could help answer some of the fundamental questions that remain about the universe.
"We happen to be using black holes to map out what space-time is doing, like, what happens at the edge of a black hole? What happens when something gets swallowed? All those same questions that kids have, we're still trying to figure out," Adhikari explains. "LIGO-India will be the first time we'll make this new map of the sky that will show us the polarization of all of these things. It'll be like a bug's-eye view of the universe that helps tell the cosmic story."
Mansi Kasliwal (PhD '11), professor of astronomy at Caltech, uses LIGO to help confirm astrophysical transients-kilonovae, gamma-ray bursts, and other extreme phenomena-by correlating signals from across the electromagnetic spectrum gathered by telescopes with different measurements of gravitational waves resulting from the same cosmic blast. Combining this data is called multi-messenger astronomy, and the new observatory in India holds the potential to vastly improve the technique.
"LIGO-India adds a new long baseline to the network of gravitational-wave interferometers that dramatically improves signal triangulation," says Kasliwal, who is also director of Caltech's Palomar Observatory and originally from India. "Thus, neutron star mergers will get triangulated to a much smaller area than is possible today, and astronomers will have a much better chance to literally see the light from neutron star mergers! Seeing both photons and gravitational waves from the same source unveils astrophysics that no one messenger could probe alone."
In addition to advancing technology and providing new insights into the universe, the LIGO-India project has been assembling a pipeline of trained experimentalists. Their efforts are bolstered by a long-standing collaboration with Caltech, in which the summer undergraduate research fellowship (SURF) program brings Indian students to the Institute for hands-on research experience with LIGO instrumentation.
"I've been having undergrads come over for over a decade and some of them have gone on to do PhDs in this field," Adhikari says. "They're kind of my secret power. I'm hoping to call on those people to maybe move back to India and work on LIGO or even send their own students to learn there."
Indian institutions are responsible for building the site systems, civil infrastructure, and significant interferometer hardware as well as all installation, commissioning, and long-term operations. More than 60 Indian institutions and hundreds of scientists, engineers, and students are expected to contribute to the project over its lifetime.
