On September 14th 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) made a major announcement they had detected gravitational waves for the first time, from a pair of massive black holes more than a billion light years from the Earth. This spectacular measurement was a result of these two black holes merging together, producing ripples in the fabric of space-time. Their detection confirmed the theoretical predictions of Albert Einstein and represented our first ever direct detection of black holes. LIGO estimated that the power radiated during the final moments of the black holes merging was about 50 times greater than the combined light power from all the stars and galaxies in the observable Universe.
Albert Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity. His theory showed that massive accelerating objects (such as neutron stars or black holes orbiting each other) would disrupt space-time in such a way that ‘waves’ of distorted space would radiate from the source (like the ripples from a stone thrown into a pond). These ripples would travel at the speed of light through the Universe, carrying information about their origins and clues into the nature of gravity itself.
The gravitational waves that are detected by LIGO will be caused by some of the most energetic events in the universe – colliding black holes and even the birth of the Universe itself – by detecting these waves, we will be able to observe the Universe in a way not previously possible.
This Festival talk by Joe Giaime, head of LIGO Livingstone observatory, will tell the amazing story of this discovery. Join him and learn about the amazing technology behind the LIGO detectors, which can measure the signatures of spacetime ripples less than a million millionths the width of a human hair, and explore the exciting new possibilities of gravitational-wave astronomy.