Originally posted to 13.7 Cosmos & Culture on February 10, 2016
I'm writing this with the expectation that on Thursday, Feb. 11, 2016, the biggest science story since the discovery of the Higgs particle will be all over the news.
With that in mind, please allow me to recount my own personal history that led to this moment:
- 1988: I'm a young physics graduate student at the University of Washington. Some guy comes and gives a talk about Einstein's Theory of Relativity and its prediction of gravitational waves: traveling ripples in the fabric of space and time. Sounds cool to me. Someone asks when we'll be able to see these waves. The guy says soon, if they can get the money to build a big detector.
- 1994: I'm a post-doctoral astrophysics researcher at the University of Minnesota with two small kids. Some guy comes and gives a talk about the two big gravitational wave detectors they got money to build. The project is called LIGO (Laser Interferometer Gravitational-Wave Observatory). Sounds cool to me. Someone asks when we'll be able to see these waves. The guy says soon, but first they have to construct the miles-long laser "telescopes."
- 2002: I'm an assistant professor of astrophysics at the University of Rochester. Some guy comes and gives a talk about the two big gravitational wave telescopes now up-and-running Washington and Louisiana. Sounds cool to me. Someone asks when we'll be able to see these waves. The guy says soon, if they're lucky. But there is a lot work that needs to be done calibrating the systems.
- 2007: I'm an associate professor of astrophysics at the University of Rochester. Some guy comes and gives a talk about the status of LIGO. They are starting to upgrade the systems to become more sensitive to gravitational waves. Sounds cool to me. Someone asks when we'll be able to see the waves. The guy says soon, once the upgrade is done.
- 2012: I'm a full professor of astrophysics at the University of Rochester. My kids are in college, my hair is showing a lot of grey and I need to back way off on the big bump runs when I ski cause my knees hurt. Some guy comes and gives a talk about the status of LIGO...
I think you get the picture.
All my professional life I have been sitting in scientific talks about detecting — directly "seeing" — the vibrations of space and time called gravitational waves. At some point, after all those years, I began to think: "Hey, maybe this isn't going to work. Maybe it's just too hard or too subtle."
It will be a beautiful thing to find out I was wrong.
The long, long wait to get to a direct detection tells us a lot about why gravitational waves are so important and why the announcement will be such a triumph.
Einstein's vision that space and time are really a single flexible, stretchable fabric is just as stunning an idea today as it was when he first proposed it 100 years ago. Soon after he first announced his theory, he published another paper showing that any movement of matter — even wiggling your hands back and forth — would produce traveling ripples in this space-time fabric.
Just like water waves disturb the surface of a pond after a rock is dropped into it, these gravitational waves distort space-time, causing distances to shorten and lengthen as they pass.
But these changes in space and time are so utterly tiny that they're extremely hard to detect. Only the most violent and cataclysmic events, like two black holes eating other, will produce gravitational waves strong enough that we could even hope to see them. The reason for this is that space-time may be a fabric — but it's a pretty stiff one.
That is why it took so long to make a working gravitational wave detector. Only by using crossed lasers running through miles-long tubes could we get the ultra-high sensitivity yardsticks needed to see waves squeezing and stretching space. The effort required an army of smart, dedicated women and men working tirelessly for decades to refine LIGO and develop the understanding of Einstein's grand theory required to make it usable. It took that long and required that much effort to show us something remarkable — reality itself is ringing like a bell.
But now, we expect to be told, we can finally see gravitational waves directly. This is like someone who is blind to the color red — and all things red — suddenly waking up to a world with apples and roses and Valentine's Day cards. This would mean that, using LIGO as a gravitational wave telescope, we've just opened up an entirely new window on a universe of black holes, neutrons, stars and, perhaps, even the Big Bang itself.
That is why today's announcement matters.
It's about patience and effort in the service of that most precious of human experiences: wonder. We can be proud to be part of a species that has gained such an understanding of the world. We can also be proud to be part of a nation that is willing to spend some of its hard earned treasure just to gain that understanding.
But, most of all, we can look out at the night sky and just be filled with wonder.
- The Astrophysical Journal