GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole CoalescenceRead more...
The Right Place At The Right SpacetimeRead more...
Observation of Gravitational Waves from a Binary Black Hole MergerRead more...
Posted by PB on February 18, 2016
The Right Place At The Right Spacetime
by Alex L. Urban
JULY, 1997. Ashtabula, Ohio. A 9-year-old boy, whom some would call "precocious" but most would simply label "really, really weird," goes to the movies with his father. The film: Carl Sagan's Contact, starring Jodie Foster as a very dedicated scientist. It's a pretty good movie, the boy thought, his mind feverishly trying to calculate the incredible vastness of space, totally enchanted by the way everything up there seems to be so elegantly connected. He couldn't have known then, but this summer popcorn flick would turn out to be life-changing.
I have always gauged life's little successes by whether 9-year-old Alex would be happy to hear about them. And a deep, almost spiritual fascination with astronomy has always been part of my life – from age 5, when my mom patiently helped me become pen pals with NASA – but I have known since that day at Nickel's Theater that I wanted to devote my life to it. There was simply no other choice. I wanted to be one of those devastatingly cool people I saw on the screen, manically bouncing from computer bank to TV monitor, glancing at mad scientist equipment and shouting things I didn't really understand about M31 and the star Vega and prime numbers and the 21 cm Hydrogen line. Those folks sure sounded important.
Then in autumn 2015, something sort of insane happened. That naive and romanticized image in my mind, from a childhood memory of a place long ago and far away? It became a profound new reality.
I came to UW-Milwaukee in 2010, fresh out of college and enthused about the Ph.D. program. At the time I had lofty goals of being a theoretical physicist, something like a less streetwise Stephen Hawking. My advisor, Patrick Brady, put up with this for a short while before managing to talk some hard sense into me. "You should join LIGO," he recommended. "It'll be much, much easier to find a real job that way." (In the end, it always comes down to life planning.)
Patrick's thoughtful advice has always gone a long way, and he eventually won me over. I joined the LIGO Scientific Collaboration (LSC) in late 2012 and spent the first few months memorizing the 1,000,000,000 or so acronyms. (LIGO itself stands for Laser Interferometer Gravitational-wave Observatory, for any latent Scrabble enthusiasts.) Before long I became heavily involved in what we in the business would call "Multimessenger Astronomy": the effort to follow up gravitational wave detections by LIGO with observations from gamma-ray, X-ray, optical, and radio telescopes scattered across the world and in outer space.
“Yeah, this'll do,” I thought. 9-year-old Alex concurred.
As you might imagine, the process of multimessenger astronomy is far from easy. We have to move quickly if we're going to catch the explosive signature of two colliding neutron stars, for example – the X-ray and optical counterparts are expected to begin only a few minutes after LIGO detects a merger! In those few minutes, we need to figure out where on the sky it came from, do basic data quality checks, filter out any obvious earthquake activity or the like, and then broadcast an alert to astronomers that says, "Look! We (might have) found something!" Not only does this demand specialized computer architecture, but also a real-time alert system (which is maintained by our friends at NASA). It is also challenging sociologically: how do we bring thousands of scientists, including people who work on instrumentation and data analysis for several different kinds of instruments, all together and on the same page? And how do we do it quickly?
“Sweet, a challenge!” I thought. There are people in this world who claim to work well under pressure; I on the other hand work exclusively under pressure. I simply won't get things done without it. (Just ask Patrick.)
In autumn 2015 I agreed, reluctantly at first, to visit one of the LIGO detectors in Louisiana as part of the LSC Fellows program. Patrick suggested the idea to me in the spring, but I wasn't buying it. Why me? I thought. I'm a data analyst; I have no business being at the detector. It would be a waste of their time to train me. Worse, I have to start writing a thesis! Where would I ever find the time to take on all these projects? But Patrick gave me the hard sell and we reached a compromise. I would go to the LIGO Livingston Observatory (45 minutes outside of Baton Rouge) and I would stay there for three months, bringing the various operators and detector engineers up to speed on multimessenger astronomy, and working with the friendly data quality folks on their fast decision-making.
I arrived in Baton Rouge on 6 September, just before the first Observing Run started. It was a 40-minute-or-so jaunt from my apartment to the site, and I began work in Middle-of-Nowhere, LA, the next day. Almost as soon as I got there, the Universe went totally crazy.
It was around 4:50 in the morning on 14 September that LIGO made what would turn out to be the very first confirmed detection of gravitational waves, later referred to as GW 150914 based on the calendar date. From the time-frequency structure of the signal (which you could pick out by eye!) we understood immediately that, if it's real, it's got to be due to the inspiral of two black holes roughly 30 times the mass of the Sun.
At this point, 9-year-old Alex dropped his proverbial toy space shuttle and stuttered "W-WHAT?! GET OUT!!" at the top of his lungs. I imagine you, dear reader, having the equivalent grown-up reaction.
Within two hours I was awake and in a car, on my way into the LIGO site for work. I didn't realize the full impact of what happened until I got there. The mood at LIGO Livingston was jubilant, almost surreal. There were people at the Observatory who have been in this game for more than 20 years, while I'm just some young punk still making a name for myself – I can't imagine what this must've been like for them. Think about it: there were good reasons to believe this thing was real right from the off, and for the LIGO veterans, this was a career-affirming milestone that happened literally overnight.
For me personally, it was a boyhood dream come breathtakingly true: I really was one of those people shouting smart-sounding science-y things from a bank of impressive computer monitors. Or rather, that day, 9-year-old Alex was.
That was only the first week of my trip to Louisiana. What about the remaining three months? Well, it was very fruitful work-wise. I spent most of that time getting some very intelligent people to sit down and talk to one another, and I worked with my good friends Jess, Duncan and Reed on ironing out a solid plan for what to do in the future, when things like GW 150914 hopefully happen again. With other off-site collaborators, I helped astronomers train their telescopes on GW 150914's location. We didn't expect to find any X-ray, optical or radio signatures for GW 150914 because the signal was due to two black holes colliding (and therefore there's no way for light to be produced), but the Universe has surprised us before. Analysis of data from these telescopes remains ongoing. Other things happened, too: the site coordinators at Livingston and the other detector in Hanford, Washington, assembled a Rapid Response Team, referring to the people who would need to get woken up to make decisions about whether to send an alert to astronomers. (I think a better name for us would've been the Science Avengers, but that's just me.)
I also made a famous best friend. Neil deGrasse Tyson, his wife and son randomly popped in to the Livingston site for a visit one day, and very kindly took the time to talk to us. That experience was a uniquely incredible one – I wasn't starstruck until later that day, after I had already got to talk to him about public outreach (something very near and dear to my heart) for nearly 45 minutes...
Where do we go from here? GW 150914 is very exciting on its own terms. LIGO has not only made the first confirmed detection of gravitational waves; we have direct evidence that black holes exist and form in binaries. We have performed the first strong-field tests of Einstein's theory of General Relativity, nearly 100 years to the month after he first published it. (By the way, Einstein came out in the right once again.) Like a child standing up and slowly working out how to understand sound for the first time, we have opened up a new sense onto the Cosmos. This really is one for the history books. And I, Alex Urban, a random boy from small town Ohio, get to tell my family that I was not only a part of it but I was there on the ground when it happened.
Anyone would be lucky enough to live out a childhood dream. To be a part of history in the process is, well... it's kind of soul-affirming.
* This research was made possible by the National Science Foundation, the UWM Research Growth Initiative, the unconditional support of incredible people like my loving mother and father, my grandmother-type-guy, aunt Julie, and Patrick Brady, and by Viewers Like You. Thank you!