China to launch first satellite in hunt for gravitational waves
Three satellites will form an equilateral triangle of laser links around the earth to hunt for gravitational waves
China’s first satellite for its space-based gravitational wave detection program, Tianqin, is set to embark on its trek to space by the end of 2019.
The program was initiated by cosmologists from Guangzhou’s Sun Yat-sen University in 2015, with the ultimate goal of launching three purpose-built satellites to form an equilateral triangle around the earth.
“It’s like a harp (tianqin) in space. If the gravitational waves come, the ‘harp’s strings’ – laser communications among the three satellites – will be plucked,” said Luo Jun, president of Sun Yat-sen University and a member of the Chinese Academy of Sciences.
Luo told Xinhua that detection will be based on high-precision laser interferometry technology to measure the changes of the distances and locations of the three satellite probes.
Gravitational waves are “ripples” in the fabric of space-time caused by some of the most violent and energetic processes in the universe. Albert Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity.
The first-ever discovery of gravitational waves by the US Laser Interferometer Gravitational-Wave Observatory, announced in February 2016, has encouraged scientists worldwide to press ahead with their hunt for the disturbances in space.
The Chinese space-based probes will be used to detect gravitational waves at much lower frequencies, and which are generated by the merging of massive or supermassive black holes, said Luo.
“Laser-ranging” is one of the pivotal technologies for such detection. China accomplished the feat in January when scientists projected a 384,400-km laser beam at the moon.
The communication relaying satellite of China’s Chang’e-4 lunar probe, launched in May, carries a laser reflector developed by Luo’s team, and is expected to extend laser projection to a record distance of 460,000 km in 2019.
The European Space Agency has also launched a space-based gravitational wave detection program, the “Laser Interferometer Space Antenna” project.