Now, it has finally succeeded in directly measuring gravitational waves, which were predicted 100 years ago in Einstein's general theory of relativity. It is the last big piece that falls into place in our theory of gravity. The measurement of gravity waves was made with the two LIGO experiments in the United States in 2015. The discovery ranks among the greatest in physics in line with the discovery of the Higgs particle in 2012 and must be high on the list for the year's Nobel Prize in physics.
Gravitational waves that are vibrations in the space-time structure itself occur when large masses are accelerated sharply. The event seen by LIGO came from two black holes more than one billion light years away that melted together. In the last fraction of a second, gravitational waves were sent out with an energy that, for a short moment, exceeded the sum of the energy from all other objects in the universe.
While the existence of gravitational waves is a cornerstone of physics, they open a completely new window for observing extreme events in the universe. With LIGO, and upcoming space-based gravitational wave detectors like LISA, astrophysicists get a whole new tool to study black holes and neutron stars in unprecedented detail. And not least, Discover brand new phenomena that nobody has thought of!