A century ago, Albert Einstein - a great scientist - developed many of the ideas we have today about relationships between gravity in space. He predicted that something special would happen when two bodies such as planets or stars orbit each other. He believed this kind of movement caused ripples in space. These ripples, known as gravitational waves, would then spread out like ripples in a pond when a stone is dropped through the water's surface. Little did Einstein know 1.3 billion years ago, two massive black holes collided. This collision released massive amounts of energy in a fraction of a second sending gravitational waves in all directions. On September 14, 2015 those waves finally reached Earth and were detected by researchers at the Laser Interferometer Gravitational wave Observatory - LIGO. In 1915, Enstein published a the Theory of Relativity whereby he predicted the existence of gravitational waves. In 1974, physicists discovered that two neutron stars orbiting each other were getting closer in a way similar to what Einstein had predicted. It was not until 2015, when LIGO upgraded their instruments making them more sensitive that they were able to detect the presence of actual gravitational waves - confirming the important piece of Einstein's theory.