CUHK Research: Changing the world

Gravitational-wave physics Opening a newwindow to understanding the universe “One of the grand challenges in modern physics is that 95% of the universe is dark, meaning that it doesn’t emit light,” says Professor Tjonnie Li from CUHK’s Department of Physics who has made significant contributions to the discovery of gravitational waves. “It is problematic because when we look up at the sky, nothing is visible. We see the effect, but not the universe itself.” Professor Li, heading the CUHK gravitational- wave resea rch g roup wi t h Pro f es so r Hannuksela Otto Akseli, strives to uncover and interpret signals from gravitational waves that can open a new window to understanding the universe. Gravitational waves, which can be regarded as ripples in spacetime, are emitted by anything that accelerates. The challenge is that these waves are extremely weak, and massive, explosive mechanisms are required for detection. While Albert Einstein predicted the existence of gravitational waves a hundred of years ago, he noted that these waves were too weak to be measurable. Today, technological advancement has made it possible – In 2015, they were first detected by the twin Laser Interferometer Tjonnie Li Associate Professor of Physics Source: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/ 74