TESTING EINSTEIN

How attempting to break the theory of general relativity has migrated beyond the limits of the Milky Way

- Robert Lea

Testing Einstein’s geometric theory of gravity, or general relativity (GR), was never going to be a straightforward task. At the heart of GR are the effects that massive objects such as planets, stars and even entire galaxies cause on the fabric of space. Such tremendous masses aren’t easily replicated in the lab, especially before the debut of complex computer simulations. In the century since its introduction, physicists have moved GR experiments into space, out past the limits of the Solar System and even beyond our galaxy.

“Space is the most ideal laboratory for testing general relativity, as its effects in and around the Solar System are so minuscule,” Vivek Venkatraman Krishnan, an astrophysicist at the Max Planck Institute for Radio Astronomy, Germany, explains. “The effects of GR are significant only around objects that have strong gravitational fields – such as neutron stars and black holes – which makes them ideal laboratories for testing.” During this journey, scientists have studied some of the most powerful and mysterious objects in the universe.