David Reitze, executive director of the U.S.-based Laser Interferometer Gravitational-Wave Observatory¹, also known as LIGO, made the announcement in Washington D.C.

"Ladies and gentlemen, we have detected gravitational waves, we did it!"

The gravitational waves that were detected were produced during the final fraction of a second of the merger³ of two black holes as they produced a single, more massive spinning black hole.

This collision of two black holes had been predicted but never observed.

The astronomer⁴ also gave a simpler explanation on gravitational waves using ripples⁵ in a pond as a metaphor⁶.

"Gravitational waves, sort of at a fundamental level, are very similar to that. In this case, the rock, is some big massive object, some accelerating object, and the surface of the pond is the space. It's basically a space. So when a big object moves and accelerates, you have two objects, orbiting around one another, it's creating these ripples that travel outward, and that's what a gravitational wave is. It's like ripples on a pond, but the ripples in this case are in space themselves."

The gravitational waves were detected on Sept. 14 last year by the twin LIGO detectors⁷, located in Livingston, Louisiana; and Hanford, Washington State.

Based on the observed signals, LIGO scientists estimated that the black holes involved in the event were about 29 and 36 times the mass of the Sun, and the collision took place 1.3 billion years ago.

Mass, about three times that of the Sun, was converted into gravitational waves in a fraction of a second -- with a peak power output about 50 times that of the whole visible universe.

John Mather, a senior scientist at NASA, says the discovery may prove it is possible that a binary⁸ black hole could exist.

"We know from previous work that neutron⁹ stars, which turn into pulsars, can be binary, that they can be in pairs. We never knew for sure that they would be stars that could turn into black holes in pairs and then merge² together to form this coalescing¹⁰ black hole and make this huge burst of gravitational energy to come out. This is not just a technological¹¹ accomplishment¹² in a word, and it's not just confirming that Einstein was right. This is saying that we now know something that we didn't already know about astronomy. It's spectacular."

Gravitational waves, first theorized by Albert Einstein in 1916 as part of his theory of general relativity, which is one of the two pillars of modern physics, are extraordinarily¹³ faint ripples in space-time, the hard-to-fathom fourth dimension.

Some physicists¹⁴ say this new discovery provides us with a completely new way of studying the universe, and may lead to the finding of things that existed out of our knowledge.