How could you detect a faint tremor in the very fabric of space-time itself? How could you possibly measure a tiny stretching and compression a mere one ten-thousandth of the diameter of a proton? And why would you want to? That’s what Black Hole Blues is all about.

Just over a century ago, Albert Einstein developed his General Theory of Relativity, which interprets gravity as a deformation of space-time caused by the presence of matter. One of the more obscure predictions of the theory was that the acceleration of a large mass should cause ripples in space-time: gravitational ‘waves’. No one at the time could have imagined that such tiny ripples could ever actually be detected. Einstein himself vacillated about whether such waves would indeed exist.

Nevertheless, in the mid–1970s the first evidence was gathered that accelerating masses did indeed emit such waves, though it was indirect evidence. A binary system of orbiting neutron stars was shown to be losing energy as the two stars spiralled closer to each other. Where was the energy going? Only gravitational waves seemed to fit the bill.

Knowing that gravitational waves exist is one thing: actually being able to ‘hear’ them is another.

This book, then, is about the decades-long struggle to find a way of detecting such waves. Only the most cataclysmic of astronomical events such as the collision of massive stars or the merging of black holes could be expected to generate ripples we might have a chance of detecting. Even then, the ripples would be almost unimaginably small. Yet a small group of scientists persisted in believing that there were ways it could be done.

Of course, a scientifically-literate reader today knows that it was done. Gravitational waves were first detected in 2015. But the bulk of Black Hole Blues was written before that detection. That doesn’t detract from the interest of the book, which details the individuals

3 involved in trying to build detectors, or at least in the early days, in figuring out what technology they would need to develop in order to build a detector.

The author introduces us to the many talented scientists involved in this drawn-out process, which started in the late 1960s. It is as much a story of the conflicts between genius-level personalities, and about the funding challenges and politics, as it is about the actual science. This is science in the raw, a struggle of human beings striving to understand the universe but also caught up in normal human concerns: about having and keeping a job; about dealing with difficult colleagues and bosses; about finding enough support and money to keep going; about the lure of prestige and honours.

It also demonstrates that science is a self-correcting endeavour, as it discusses the case of Joseph Weber, who convinced himself, and for a while the scientific community, that he was detecting gravitational waves in the harmonic ringing of a massive bar of metal. But others were unable to reproduce his results, and theorists showed that such a detector, even if it worked, would only detect astronomical events of an unlikely magnitude and frequency. This was not scientific fraud; merely an error of technique. But Weber would never accept that he had been wrong, and became a sad footnote to scientific history.

Though this setback tainted the study of gravitational waves for some years, a small group at Caltech and M.I.T. kept pushing on with an effort to achieve detection using laser interferometers. Eventually their efforts, and generous financial support from the U.S. National Science Foundation led to the building of two instruments called LIGO, one in Washington State, the other in Louisiana. It was these two instruments which, after achieving a high level of sensitivity, both registered the first gravitational waves in September 2015, as described in an Epilogue to the book.

Black Hole Blues is well worth reading if you are interested in how science is actually done, and particularly if you are interested in this facinating new window on the universe. ( )

The story of the people behind the Gravity wave experiments is brought to life. I liked the vivid depiction of the characters involved and the workings of science. The book was missing some insight and conjecture: more ideas about the phenomenon that I didn't already know. ( )

A pair of stars orbit around each other several billion years ago. They die a billion 400 million light years away from us. They decay into two black holes. The black holes orbit around each other and eventually collide creating a massive interstellar kaboom. In 2015, the sound waves eventually reach earth where a team of Caltech and MIT scientists have recently completed a massive interferometer to catch the sound waves and give us our first physical proof of black holes almost exactly one century after Einstein published his scientific paper on gravitational waves predicting the existence of black holes. Sounds like fiction, no. It actually happened. ( )

Fascinating history of the people and science behind the detection of gravitational waves. Surprisingly exciting stuff. ( )

Compelling But Not Well Written

Which is a shame, I would love to read a better account of the project and the people involved. Will seek more out. ( )