As predicted by Albert Einstein

Gravitational WavesWere Black Hole Gravitational Waves predicted by Albert Einstein himself and Einstein's theory of general relativity?

Albert Einstein seemed to have some doubts about Gravity Waves and changed his mind on the subject. Albert Einstein also seemed to not believe that black holes were possible.

Yet some reports on the aLIGO experiment to find GW's produced by the merger of a binary black hole system seem to imply that Albert Einstein predicted the whole 2 black holes merging etc.

It is the first ever direct detection of gravitational waves; it's the first ever direct detection of black holes and it is a confirmation of General Relativity because the property of these black holes agrees exactly with what Einstein predicted almost exactly 100 years ago.
Prof Alberto Vecchio | BBC

Almost 100 years ago, in February 1916, Einstein first mentioned gravitational waves in writing. Ironically it was to say that he thought they did not exist! Within a few months he changed his mind and by 1918 had published the basis of our modern theory of gravitational waves, adequate to describe them as they pass by the Earth. However his calculation does not apply to strongly gravitating systems like a binary black hole.
Daniel Kennefick, University of Arkansas - Gravitational waves discovered—top scientists respond | Phys.org

Gravitational Waves

“The description of this observation is beautifully described in the Einstein theory of general relativity formulated 100 years ago and comprises the first test of the theory in strong gravitation. It would have been wonderful to watch Einstein’s face had we been able to tell him,” says Weiss ... Bruce Allen, managing director of the Max Planck Institute for Gravitational Physics (Albert Einstein Institute), adds, “Einstein thought gravitational waves were too weak to detect, and didn’t believe in black holes. But I don’t think he’d have minded being wrong!”
Gravitational Waves Detected 100 Years After Einstein's Prediction | LIGO

Albert Einstein first predicted gravitational waves in 1916 based on his general theory of relativity, but even he waffled about whether or not they truly exist.
Gravitational Waves Discovered from Colliding Black Holes | Scientific American

Einstein was not quite sure about these waves. In 1916, he told Karl Schwarzschild, the discoverer of black holes, that gravitational waves did not exist, then said they did. In 1936, he and his assistant Nathan Rosen set out to publish a paper debunking the idea before doing the same flip-flop again.
Gravitational Waves Detected, Confirming Einstein’s Theory | The New York Times

His theory of General Relativity suggests that objects such as stars and planets can warp space around them - in the same way that a billiard ball creates a dip when placed on a thin, stretched, rubber sheet ... Einstein predicted that if the gravity in an area was changed suddenly - by an exploding star, say - waves of gravitational energy would ripple across the Universe at light-speed, stretching and squeezing space as they travelled.
Einstein's gravitational waves 'seen' from black holes | BBC

Gravitational Waves

Albert Einstein explained that what we perceive as the force of gravity in fact arises from the curvature of space and time. He found that space and time were actually interwoven into a single continuum known as space-time. As he worked out the equations for this general theory of relativity, Einstein realised that massive objects caused a distortion within this continuum ... He proposed that objects such as the sun and the Earth work in a similar way. In the presence of matter and energy they can evolve, stretch and warp, forming ridges, mountains and valleys that cause things moving through to zigzag and curve.

Einstein determined that massive objects (like the Earth) cause a distortion in space-time which is felt as gravity.
An idiot's guide to the Theory of Relativity | Telegraph

“We think black holes exist out there. We have very strong evidence they do but we don’t have direct evidence,” Lehner says. “Everything is indirect. Given that black holes themselves cannot give any signal other than gravitational waves, this is the most direct way to prove that a black hole exists.”
Gravitational Waves Discovered from Colliding Black Holes | Scientific American

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it's the first ever direct detection of black holes and it is a confirmation of General Relativity because the property of these black holes agrees exactly with what Einstein predicted almost exactly 100 years ago."
Einstein's gravitational waves 'seen' from black holes | BBC

They have observed the warping of space-time generated by the collision of two black holes more than a billion light-years from Earth.
Einstein's gravitational waves 'seen' from black holes | BBC

“Einstein, when he came to write down his theory of gravity, his two heroes were Faraday and Maxwell,” said Turok. “He tried to write down laws of the gravitational field and he wasn’t in the least surprised to discover that his predictions had waves, gravitational waves.”
Gravitational waves: breakthrough discovery after a century of expectation | The Guardian

News articles headlines proclaiming Einstein’s predictions

Einstein nailed it! Gravitational waves do exist | CNET
Einstein was right: Scientists detect gravitational waves in breakthrough | CBS News
Gravitational waves detected, proving Einstein right again | CNN
Gravitational Waves Detected, Confirming Einstein’s Theory | The New York Times
Gravitational waves: Einstein was right | Telegraph
Einstein's gravitational waves 'seen' from black holes | BBC
Gravitational Waves Detected 100 Years After Einstein's Prediction | LIGO
Einstein predicted gravitational waves 100 years ago; here's why you should care | First Post
Einstein Proven Right 61 Years After His Death | Inquisitr