One hundred years ago, Albert Einstein predicted the existence of gravitational waves through his theory of general relativity. Yesterday, an international group of scientists leading the LIGO (Laser Interferometer Gravitational-Wave Observatory) announced the first direct detection of these waves. This discovery not only concludes a race that lasted nearly a century, but also opens an entirely new field of research.
The LIGO Experiment
The LIGO experiment (Laser Interferometer Gravitational-Wave Observatory) was born in 1992 as a sustained effort by several universities, including MIT and Caltech. In total, more than 900 scientists from around the world have collaborated with LIGO to make a single discovery: detect gravitational waves. The first time these waves were discussed was between 1916 and 1918, when Albert Einstein published papers anticipating their existence. LIGO "listened" for thirteen years, until September 14, 2015, when, after some upgrades, the results arrived. When we say "arrived", it is with very special emphasis, because the waves traveled for 1.3 billion years at the speed of light.
The Detection Announced Yesterday
In yesterday's official announcement, LIGO's executive director David Reitze and several members of the scientific team shared specific details with the press. Gravitational waves are caused by events of chilling magnitude, and in this case, their origin was the approach, collision and inevitable merger of two black holes with approximately 26 and 39 solar masses. How sure are they? Matthew Evans, a physics professor at MIT and one of LIGO's collaborators, spoke of "Sigma 5.1 at a minimum", meaning the probability of error is one in six million. This LIGO result is, by far, the most precise measurement ever made by the human species.
Why This Discovery Matters
Why is this detection so important? Well… where do we start? Scientists have said several things in the last few hours. First, it opens the doors to gravitational astronomy. Second, it confirms the existence of black holes. And third, it reveals the first "merger" of black holes, something that until now was just a prediction. In the name of scientific skepticism, the only path is to continue researching and accumulating data, but we cannot deny that those responsible feel very happy, and very confident, with this discovery. Could a Nobel Prize be on the horizon…?
