EDITOR’S NOTE

— Joining the welcome chorus

GIVE YOURSELVES a hearty slap on the back for being a member of the species that discovered gravitational waves!

Cosmos covered the announcement online. Here in the magazine two of our columnists give voice to their elation and there’s a wrap-up feature. But I can’t help joining the chorus. This discovery resonates on so many levels.

There’s the personal. I recall being startled when my son Alex, as a child of eight or nine, asked me whether gravitational waves exist. On 11 February, I delighted in telling the grownup lad: yes they do.

There’s the prophetic. Einstein predicted them 101 years ago from his bizarre theory of General Relativity. Time was a fourth dimension woven with the nothingness of space to create the fabric of space-time. Gravitational waves might ripple through that. Now, with the final proof of Einstein’s theory, we must entertain the truth of our bizarre Universe. We are going to get to know it in a profoundly new way. Gravitational waves are incredibly weak yet propagate through anything. So we can probe things that were blocked to us before – from the events inside an exploding star to the beginning of the Universe in the Big Bang. Suddenly the movie Interstellar seems less like sci-fi. Then there are the mind-blowing contrasts. Physicists figured out that, gravitational waves being so weak, the best chance of detecting them would be to shoot for the most cataclysmic events in the Universe – the merger of two black holes. They figured right. But where do such events take place? Not in the Milky Way. To find one, the LIGO machines probed space-time in the range of 190 million light years from here. And to detect such a wave, the machine measured a distortion of space-time one ten thousandth the size of the nucleus of an atom. Trying to imagine the unimaginable at both scales makes my poor head wobble.

Then there’s the crazy scientist angle. What possesses scientists to go hunting for something as immeasurable as the flapping of an angel’s wing? Einstein himself thought gravitational waves would be too weak to detect. It took a few very brave pioneers like Joseph Weber at the University of Maryland, Australia’s own David Blair at the University of Western Australia and Caltech’s Kip Thorne, who devoted their lives to establish that this might not be as crazy as it sounds.

And then it took about 1,000 more to bring it to fruition. Ultimately building LIGO was not rocket science. It was done by a group of obsessional people in pursuit of perfection: perfect stillness, perfect cleanliness, perfect mirrors, perfect steering of laser beams, perfect data analysis. Some 50 of these strange types came from Australia.

Two decades ago they realised they were a 1,000-fold out on all these measures. Any sensible person would have walked way. They didn’t.