High school physics has taught us (hopefully) what waves are and the characteristics that define them. Simply put, waves are something that transfers energy. Perhaps the most quintessential example is, when a pebble is dropped in a pool of still water, waves ripple from the point of impact, indicating the transfer of energy outward.
Now, imagine this: two black holes, both around 30 times the mass of the sun, collide with speeds approaching the speed of light. The resulting energy released must be enormous! Perhaps enough to even solve the energy crisis millions, maybe billions, of times over.
This event occurred a little more than a billion years ago, resulting in the propagation of gravitational waves from the point of impact. However, the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO), detected the presence of such waves just weeks ago 2. This means that when this collision occurred, dinosaurs were probably roaming the Earth, suggesting the unfathomable distance that separate Earth from these black holes.
Gravitational waves are simply disturbances in space and time. Einstein viewed mass as being capable of bending space, leading to the force of gravity. For instance, earth exerts a force of gravity on us because it can bend space much like a marble that rolls toward a person standing on a trampoline. The collision between the black holes led to disturbances in space that have reached Earth.
Why this is such a remarkable event lies in how it affects our current understanding of Einstein’s theory of relativity. While Einstein predicted the existence of gravitational waves, a topic on which he would frequently oscillate, it is important to note that this discovery is notable for offering a new perspective at looking at reality that Einstein couldn’t have even predicted.
Firstly, gravitational waves prove quantum entanglement, a concept that Einstein rejected because it was “spooky” 1. Quantum entanglement simply suggests that two objects, irrelevant of the distance between them, can influence each other. This means that a massive star situated a billion light years away (a big distance), can produce disturbances in space and time that can, albeit to a small extent, influence a baseball that is thrown in the air or vice versa.
You have probably have heard that black holes have such a great mass that even light cannot hope to escape. This phenomenon, called gravitational lensing, was suggested by Einstein but qualified its discovery by saying that a direct discovery was impractical 1. However, the LIGO discovery provided the direct evidence. While Einstein only considered how stars influence the lensing, recent scientists working for LIGO considered galaxies; the larger mass of galaxies compared to stars made the lensing phenomenon more apparent.
Lastly, Einstein coined the term “cosmological constant,” 1 representing a repulsive force to counter the force of gravity. Implicit in this idea is that the universe is static – or so Einstein believed. As it turns out, Einstein showed, without realizing it, that the universe is expanding in his “mathematical blunder.” 1 How is this relevant to the recent discovery? According to NASA, this constant apparently plays an adept role in describing how dark energy behaves.
Though the discovery of gravitational waves has given credence to one of Einstein’s theories, namely quantum entanglement, it also sheds light on his mistakes. These mistakes, however, have led to a greater comprehension of the universe and can, perhaps, even offer a different set of lens which we use to view the world.
1 – http://www.nytimes.com/interactive/2016/02/12/science/when-albert-einstein-was-wrong.html?_r=0
