The announcement of the observation of gravitational waves for the very first time ever has been all over social media in the past few days. It is being described as one of the greatest discoveries, confirming the theory of general relativity that was concocted by Einstein himself decades and decades ago. Scientists promise that the new findings will help us dig further into the nature of our universe. But, what exactly are these gravitational waves that everyone is talking about?
A gravitational wave is an oscillation in space-time created by a gigantic object or two such objects combining or simply moving about. Everything in our universe is thought to produce these waves but they can only be detected when coming from massive events like ones involving black holes; it is only measurable from such great events. The wave has also been described as a “ripple” by Justin Greenhalgh from LIGO, the organisation behind the discovery.
The wave that has been observed resulted from the merging of a pair of black holes: when these two became one, the energy they released as they lost mass equivalent to three of our Sun led to the formation of a ripple in space-time which is the gravitational wave. This event occurred 1.3 billion years ago, and we have detected it now, that is, the wave travelled 1.3 billion light years to us; fortunately, the LIGO detectors were switched on when it passed over us.
Everything started when two of LIGO’s detectors spotted a signal. The subsequent calculations and deductions that ensued from this detection led the scientists to theorise that it must have come from the merging of two black holes. The figures allowed them to estimate the size, mass, and age of the black holes.
The wave reached us because it is said to propagate forever from its source; the energy released causes it to travel in all directions at the speed of light. But, the waves do get weaker the further they go.
Why are scientists saying the discovery would help us study the universe further? This is because gravitational waves are a form of information just like radio waves are. They could potentially allow us to learn of unexplored parts of the universe. The event at hand itself is an ideal example: despite being 1.3 billion light years away, we could learn of their presence and their merging.