Gravitational waves is a strange phenomena which was predicted already by Albert Einstein. To understand gravitational waves you need to understand gravitation. In this podcast professor Niels Obers describe gravitation in Newtonian terms and in the frame of Einstein's general theory of relativity. Both descriptions are incomplete but due to research with gravitational waves we may reach to a better understanding of these phenomena. Since 2015 where gravitational waves were first detected with certainty, a number of new gravitational wave detectors are being build and researchers are learning more about the ripples in time, space and the fabric of the universe. Science Journalist Jens Degett from Science Stories is interviewing professor Niels Obers from the Niels Bohr Institute at University of Copenhagen.