Fly with the spaceship through the galaxy and save the astronaut from being swallowed by black holes, which even you should not get too close to. In three levels you have the opportunity to prove your skills as a spaceship captain! Why are black holes black? What are gravitational waves? And what can we learn about the universe by observing gravitational waves? The app provides background information on the physics behind mass, gravitational forces and black holes, and gives insights into the s