Gravitational waves detected for the first time


Collision of two black holes detected for the first time by LIGO.
Image: SXS

The Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration announced today that it has detected gravitational waves, a discovery that opens new avenues of exploration into the history and structure of our universe. Gravitational waves carry information on the motions of objects in the universe. First predicted a century ago by Albert Einstein in his general theory of relativity, gravitational waves had not been directly detected—until now. Over 1,000 researchers from 83 organizations and universities participated in the effort, including researchers of the South American Institute for Fundamental Research (ICTP-SAIFR), a UNESCO Category 2 Centre affiliated with the International Centre for Theoretical Physics (ICTP)*.

Gravitational waves are produced by massive accelerating objects in the universe such as neutron stars or black holes orbiting each other. Einstein predicted that their actions would produce waves of distorted space that travel through the universe at the speed of light. According to Einstein, these waves carry information with them about their origins.

Today’s announcement by LIGO means that we now have the capability to intercept those waves and study the clues they contain about our universe. The LIGO data will also be able to tell us more about the nature of gravity. “One thing you can do with the LIGO signals is to start seeing what they imply for the modification of gravity, which was predicted in General Relativity,” says ICTP cosmologist Paolo Creminelli, adding that the waves could also be used as tools to explore how black holes are formed or the features of neutron stars.

The LIGO achievement represents the work of more than a thousand scientists from 83 research organizations and universities around the world. ICTP’s partner institute in Brazil, the South American Institute for Fundamental Research (ICTP-SAIFR), is one of them.

For the past two and a half years, ICTP-SAIFR has supported a research group that collaborates with LIGO, in particular with the subgroup analysing compact binary coalescence data, information produced when two objects -such as black holes- form a compact orbit around each other and eventually merge.

* ICTP is a UNESCO Category 1 Centre; it operates under a tripartite agreement between the Italian Government, the International Atomic Energy Agency (IAEA), and UNESCO.