k hole image, two earlier detections of gravitational waves from

black hole mergers also were products of international collaboration.

In February 2016, the Laser Interferometer Gravitational-Wave Observatory in the United States announ

ced the first observation of gravitational waves generated by a black hole merger. The following June, it annou

nced the second detection of a gravitational wave event from colliding black holes.

Wu said Tianqin has potential for even greater discoveries.

“LIGO used interferometers on the ground with an arm length of 4 km. But with satellites, the arm length will increas

e to 170,000 km. So the space-based probes (enabled by Tianqin) will be able to detect gravitational waves at much l

ower frequencies generated by the merging of massive or supermassive black holes,” he said.

“It will also enable us to see the smaller black holes during the infancy of the universe, as w

ell as understand the history of black hole growth and the evolution of galaxies,” he said