In 1916, now a century ago, Albert Einstein predicted the existence of ripples in the fabric of space known as “gravitational waves”. On February 11, 2016, scientific communities from all around the world cheered when scientists announced the first direct detection of gravitational waves, ripples in the fabric of space-time. The waves came from two black holes that were circling each other, getting closer, and eventually colliding.
According to physicists, while the announcement by LIGO (Laser Interferometer Gravitational Wave Observatory) represents the first direct evidence of gravitational waves and supports Einstein’s vision of the universe in which space and time are interwoven and dynamic, it also provides powerful experimental confirmation of the existence of black holes in our Universe.
Such a major discovery was made possible by a team which consists of only three scientists: Kip Thorne of the California Institute of technology, Rainer Weiss of the Massachusetts Institute of Technology, and Ronald Drever (formerly of Caltech). Pursuing paradigm shifting discoveries are not easy tasks, and these three individuals who bet their careers on the dream of measuring these ripples in space-time should be applauded for their courage.
In an email, Dr. Thorne said, “Until now, we scientists have only seen warped space-time when it’s calm. It’s as though we had only seen the ocean’s surface on a calm day but had never seen it roiled in a storm, with crashing waves. The black holes that LIGO observed created a storm in which the flow of time speeded, then slowed, then speeded. A storm with space bending this way, then that.”
But, more importantly, Dr. Thorne and his team are extremely confident about the experimental results because the LIGO results were recorded by two separate detectors, in Louisiana and Washington State, each of which recorded the same observation.
Using Lasers for Experimental Evidence
Over the course of human development, we have always been confined to limitations of our senses. Regardless of how hard we try and push for greatness, human senses have proven that they cannot possibly convey, grasp, and understanding the unseen world around us. Decades of major scientific discoveries remind us that we are incomplete sensory beings and require new technologies to reach new plateaus.
When the microscope and telescope were invented, they opened vistas on realms that were not even suspected to exist. The fields of biology and cosmology would have remained closed to us without these instruments.
LIGO promises the same thing, and it is currently the world’s largest gravitational wave observatory and a cutting-edge physics experiment. LIGO has two enormous laser interferometers located thousands of miles apart; they exploit the properties of both space and light to detect the origin of gravitational waves and understand them.
Various fields of engineering and science also use interferometers for many different applications. They work by merging two or more sources of light to create interference patterns which can be measured. France Cordova, director of the foundation, said in an interview, “It’s been decades, through a lot of different technological innovations.”
The Evolution of the LIGO Observatory – Sensitivity Improvements
David Reitze, LIGO Executive Director of the Caltech, said, “LIGO is the most sensitive instrument ever built.” In fact, all the technological discoveries and advances made while building the observatory are likely to enable various applications that we cannot yet predict. 
According to Reitze, however, LIGO is not in the final version yet because its sensitivity continues to improve. In the future, the instruments can be sensitive enough to detect black holes that are 500 times the mass of the sun and located further away from our planet. The black holes detected by LIGO were only 29 and 36 times the mass of the sun.
The first version of the experiment started in 2000 and ran for over a decade. It is commonly referred as Initial LIGO and was mostly designed to show that it could work on the scale required. Over the course of five years, the entire system was rebuilt to increase the sensitivity to a point where scientists could realistically expect to detect these ripples.
Even with such sensitivity, only the most violent and massive events would be significant enough to make the detectors ring.
Gravitational Waves, Looking Forward
The existence of black holes has already been supported by evidence, but LIGO provides what many scientists believe is conclusive experimental evidence of their existence.   Meanwhile, Astronomers now also know that binary black holes exist, and they are rushing to explain how each one can get so big.
Meanwhile, Astronomers now also know that binary black holes exist, and they are rushing to explain how each one can get so big. Before gravitational waves were discovered, no one knew that black holes could merge to form a more massive black hole, but now there is measurable proof.
But what is truly monumental about this detection is that it gives humanity a totally new way to observe this Universe and explore its unseen connections.  Dr. Thorne is now retired from LIGO, but he said, “There just have to be big, momentous surprises, which there always have been when a new window is opened.”