By Aaron Gotkin
It is remarkable how one man alone could be so connected to the universe that his predictions and hypotheses could prove to be true even though they came from his intuition. It may sound to most as typical routine to say, “Of course Einstein was right,” but, now at the time of the latest proof of one of his predictions, his body of work appears even more extraordinary. From Special Relativity to the Photoelectric Effect, the man was brilliant. He may be the man most in tune with nature of all-time, but he himself was a freak of nature.
In 2015, The Laser Interferometer Gravitational-Wave Observatory (thankfully also known as L.I.G.O.) detected the first observed gravitational waves in human history. The waves are propagating disturbances in the fabric of space-time itself and were formed from the collision and merger of two black holes. Each black hole was the equivalent mass of 30 suns and collided approximately 1.3 billion light years away from Earth. However, at the time, the only possible observed consequences of the collision were those detected gravitational waves. The difficulty being that there was no emission of light from the event so it could not be seen. However, visibility is not fundamentally necessary for proof. The reason for the lack of visual evidence lies in the nature of black holes.
Black holes are defined as exact points in space that contain extreme amounts of mass known as a singularity. This then makes them the densest astronomical objects in the universe. Due to their absurd mass and density, they have an immensely strong gravitational force associated with them. The strength is so great that light, even being the fastest entity in the universe, cannot escape the gravitational attraction of a black hole. In fact, it sounds quite creepy, like a monster under a child’s bed that’s grip is so strong it will definitely succeed in pulling the terrified child into the darkness below. Anyhow, this property of black holes, that it absorbs all light and emits none is what makes them visually undetectable especially when two of them collide.
Black holes are defined as exact points in space that contain extreme amounts of mass known as a singularity.
If only these gravitational waves could be observed along with this desired visual evidence of light. Well, that is just what happened a few months ago. L.I.G.O. detected another collection of gravitational waves, although this time coming from the collision and merger of two neutron stars instead of black holes. This is huge because unlike black holes, neutron stars (which in themselves are intensely interesting objects) are in fact made of visible matter. They, like black holes, are dense and massive which allows for the possibility of their gravitational wave detection. However, most importantly when neutron stars collide they release tons of energy in the form of light. On October 16th 2017, L.I.G.O. announced that they detected the gravitational waves and the high-energy gamma rays from the collision of two neutron starts on August 17th, 2017. The best part of all is that the collision could be seen in the night sky with telescopes, thus giving the visual evidence associated with gravitational waves.
This great feat of human collaboration towards the proof of a scientific phenomenon, like most things in physics, relates back to Einstein. The entire project of detecting gravitational waves and the construction of L.I.G.O. was to essentially find out if Einstein was right. In 1915, Einstein completed his 10-year battle in completing his era-defining General Theory of Relativity. In his theory, Einstein described gravity as the curvature of space-time when objects of mass are placed in it. One year after the publication of his theory, using the equations of General Relativity, Einstein predicted the existence of gravitational waves. Now we have proof that he was right, once again.