When Cody Messick first visited the Laser Interferometer Gravitational-Wave Observatory (LIGO) as an undergraduate student in 2012, much of the scientific community was skeptical that gravitational waves could be detected. But Messick was undeterred. He entered the field for his Ph.D. the following year, even making a $100 bet with a friend that gravitational waves would soon be seen. Now, 5 years and several gravitational wave observations later, a neutron-star merger that Messick helped spot by analyzing gravitational wave signals is Science’s 2017 Breakthrough of the Year.
Messick, a Ph.D. student in physics at Pennsylvania State University in State College, is one of more than 3600 astrophysicists and astronomers from 953 institutions around the world who contributed to the discovery. Science Careers spoke with a few of the early-career researchers involved in the work about how they got into this field, what it was like to contribute to the breakthrough, and what they’ve learned along the way.
A programmer spreads the word
Messick was an undergraduate student in physics studying antibiotic resistance at the University of Washington in Seattle, about 320 kilometers away from LIGO’s installation in Hanford, Washington, when he arranged a field trip to the detector for his chapter of the Society of Physics Students. “I went and I was just blown away,” he recalls. Messick had always been fascinated by general relativity, and LIGO’s premise that there are observable ripples in this invisible spacetime “just totally sucked me in,” he says. So, when he went to Penn State the following year to start his Ph.D., Messick swapped cellular biophysics for astrophysics and joined the Penn State LIGO group.
It was a risky move, but for Messick this was part of the attraction. “Everyone outside the LIGO Scientific Collaboration seemed a bit more skeptical, so I found the idea of joining something that was not 100% conclusive yet really exciting,” Messick says. “Just the fact that I could have the opportunity to be on the edge of our knowledge was really appealing to me.”
To get started on building and implementing data analysis software to distinguish gravitational waves from background noise, Messick learned programming from scratch under his supervisor’s coaching while also playing catch-up on his astronomy knowledge. Changing fields requires “some persistence and even stubbornness,” Messick says, because “you are going to run into things that are disheartening and things that you don’t understand and you have to stick with it.” As for the unpredictability of the field, he took reassurance from the fact that the programming skills he was developing would prepare him for a transition to industry if need be.
The work, while exciting, can be very demanding, Messick has found. Managing real-time analyses sometimes means being woken up in the middle of the night to deal with new signals, which is exhausting when it extends over the many months of an observing run, Messick says. Back in 2015, when gravitational waves were first detected, Messick spent all night analyzing whether the signal was real so that he could present the findings to his team the next day. “The code finished running about 2 minutes before they called on me, so there are stressful times like that,” he says. But having good colleagues who, for example, were willing to step in when he wanted to take a week off to celebrate his wedding anniversary is what “makes it doable,” he adds. He has also learned to take off at least 1 day a week, even during crunch time, to fend off burnout. “Then I just felt a lot healthier, and I had a lot fewer of those days when I just could not feel motivated,” he says.
Both the pressure and the excitement multiplied as LIGO detected gravitational waves this August. Messick and his supervisor were among the first to see the signal and realize that not only was it strong and clear, it had also come with a flash of light called a short gamma ray burst—which had long been thought to be produced by neutron-star mergers—picked up by another collaboration. This simultaneous observation was “exhilarating,” Messick says. With his supervisor “shaking too much” with excitement, it was Messick who sent the email announcing the observation to the LIGO Scientific Collaboration and “getting the ball rolling.”
The theory also had it that smashed-up neutron stars then blew leftover glowing material into space. So, when LIGO identified a small patch in the sky where the explosion had likely taken place, the astronomy community jumped on board to see whether more signals were coming. “The couple of weeks after that just went crazy. Every hour, there was a new email from another collaboration that said, ‘Hey, we looked at that region in the sky; here is what we found,’” Messick recalls. “This was the birth of multi-messenger physics—the idea that [by collaborating across subfields] we can increase the scientific output from data that we’re already taking, without building new instruments.”
As the “collaboration of collaborations” then worked on writing a compendium paper that announced the discovery to the world just a couple of months later, there was intense pressure to provide the analysis quickly, Messick says. He was also working on other LIGO papers at the time, including one about an earlier detection of a black-hole merger which now needed to be published before it could be eclipsed by the neutron-star merger announcement. Working with various sets of collaborators “whose goals were not 100% aligned” had its challenges, he says. But, he continues, “the nice thing about the scientific community is that ultimately everybody wants to do the best science possible. The lack of malice makes these types of collaborations possible.”
Messick anticipates that his involvement in the neutron-star merger discovery puts him in a strong position to pursue a career in multi-messenger astrophysics, but he is also aware of his luck. “My situation has been very serendipitous,” he says. “I heard about LIGO because I decided to become an officer in a club.” His advice for other young scientists is to expose themselves to new activities and experiences, even if they seem unrelated to their core goals. “Volunteer for things, put yourself out there, because it’s the people who are there, regardless of whether or not they are looking for an opportunity, that will get that opportunity.”
A speedy astronomer strikes gold
Just a year ago, University of California, Santa Cruz, postdoc Charles Kilpatrick wasn’t very hopeful that his work scanning the skies for supernovae would contribute to gravitational wave discoveries. A lot of the techniques he used to detect the transient bright spots produced when massive stars explode could theoretically also be used to spot the cosmic show produced by two colliding neutron stars, he knew. And his adviser had set up a collaboration to search for possible neutron-star mergers as LIGO detected gravitational waves and gave astronomers a rough estimate of where in the sky they seemed to be coming from. But Kilpatrick doubted that the small telescopes he relied on for observing supernovae, which tend to be very bright, would be sensitive enough to really play a role in detecting the weaker signals that would likely emerge from a neutron-star merger. “I thought [that the discovery of neutron-star mergers] would happen eventually, but I wasn’t sure to what extent our collaboration using small telescopes could contribute to the field,” he says.
But it turned out that he had the right skills and was at the right place at the right time to play a major role. One of the telescopes involved in the collaboration, based in Chile, was ideally located for Kilpatrick to be among the first to look at the patch of sky LIGO had identified and capture, just 17 hours after the gravitational wave signal, the luminous spot that emerged from the colliding neutron stars. It was a race against the clock: Kilpatrick and his team needed to collect as much data as they could in just minutes before the Earth’s rotation made that portion of the sky inaccessible. The observations that they were able to take ultimately helped reveal that neutron-star mergers create heavy elements found on Earth, such as gold.
Like Messick, the need to rapidly compile the results for the compendium paper and write several others made life a little hectic for Kilpatrick, who says that during such times it is essential to not lose sight of all the other important aspects of day-to-day life, such as getting enough sleep; eating well; speaking with family; and, in his case, going to church. But the challenging times also proved to be a good training opportunity. Writing seven papers in just 2 months helped him hone his skills in telling a coherent story as clearly and succinctly as possible. Working on the compendium paper was also an “eye-opener” regarding the politics of large scientific collaborations, he adds. Even though his adviser was a great advocate, Kilpatrick says that he learned to look out for himself. “Sticking up for yourself and making it known what you can do and also how you contributed to each collaboration” is very important, he says.
Now, Kilpatrick expects that research into gravitational wave astrophysics will continue to play a role in his work. It’s not something he dared dive into when he started looking to the stars. But, he says, “being part of founding a new field in astronomy is probably the biggest thing that has happened in my very short career so far.”
A vacationing astrophysicist directs an orchestra of observations
When Eleonora Troja got the LIGO notification on 17 August that new gravitational waves had been detected, she dismissed it at first, assuming it was just another black-hole merger, she recalls. But as she read excited messages from colleagues that a gamma ray burst had also been detected, “I realized this was a breakthrough event,” says Troja, an associate research scientist at the University of Maryland in College Park who works at NASA’s Goddard Space Flight Center in Greenbelt in Maryland. It was the cosmic event that she had been dreaming of observing since she started learning about it as a Ph.D. student some 8 years earlier, and she couldn’t wait to dive in.
But there was a hiccup: She was on holiday at her parents’ house in Palermo, Italy. So, she hijacked her father’s TV and set up an impromptu telescope observations headquarters in her parents’ living room. It was an unconventional arrangement, but “things worked out pretty well,” Troja says. Her mother looked after her 3-year-old daughter while Troja immersed herself in the chase for a glimpse of the merger. “I barely slept for 2 weeks,” she says.
Troja remotely directed a 30-member collaboration while coordinating sky observations from facilities around the world—and vying for observation time. “Every day, I was working on a different telescope and with a different form of light,” she says. “Many people wanted to observe, and many people wanted to discover and claim their own role, so there were some unpleasant interactions. … It became a very competitive type of race.” Troja’s team went on to discover x-ray emissions from the merger, which gave clues about the dynamics and geometry of the explosion. “I was lucky that this x-ray light turned on when I was observing, but I was also very well prepared, because it takes a lot of work to get this time awarded on a telescope,” she says.
Despite the competition, which she also faced while leading her team’s contribution to the compendium paper, she encourages young scientists to put themselves forward when they see big science coming. “They should not give up too easily,” she says. “Being competitive and being driven to do a good job and being a leading scientist doesn’t equal being aggressive and unpleasant,” she adds, encouraging young scientists to choose a team or collaborators that they can get along with. If unpleasantness is inevitable, try to not take it personally, she says, because that can “poison” all the other aspects of your life. And in the end, “the excitement and the beauty of the science override anything else.”
Early on in her career, Troja decided to prioritize her personal and family life over making great sacrifices to chase a permanent position. Now she hopes that her contribution to this game-changing discovery—“the most exciting thing that could have possibly happened,” as she describes it—will help her establish herself, possibly back in Italy. She however warns young scientists against investing all their time and energy in topics as “obscure and enigmatic” as gravitational waves and colliding binary stars were not so long ago. A “good move is to always keep in your portfolio something that is a high-risk, high-impact project,” she says, but “betting everything on it might be dangerous,” as you may not be able to get results and publish for several years. “Balancing high-risk with low-risk publications allowed me to survive long enough to see the LIGO discovery.”