In early September 2015, Salvatore Vitale, who was then a research scientist at MIT, paid a brief visit home to Italy to see his parents after attending a conference in Budapest. This meeting had focused on the highly awaited power-up of Advanced LIGO — a system that researchers hoped would finally sense a fleeting disturbance in space-time referred to as a gravitational wave.
Nearly a century prior, Albert Einstein had forecasted the presence of these cosmic echoes but believed they would be unattainable for measurement. However, scientists like Vitale were optimistic that their new ripple detector might succeed, as it was due to be activated in just a few days. During the Budapest meeting, team members expressed excitement, though with a degree of caution, recognizing that it might take months or even years before the instruments could detect any encouraging signs.
Nonetheless, the day after his long-overdue family visit commenced, Vitale was met with a significant surprise.
“The following day, we detect the very first gravitational wave, ever,” he recalls. “And naturally, I had to isolate myself in a room and commence working on it.”
Vitale and his team had to operate in secrecy to ensure the news did not leak out before they could scientifically validate the signal and identify its origin. This meant that no one — not even his parents — could be informed about what he was investigating. Vitale left for MIT with a promise to return for a Christmas visit.
“Indeed, I flew back home on December 25th, and on the 26th, we detect the second gravitational wave! At that point, I had to assure them of confidentiality and explain what had transpired, or they would remove my name from the family records,” he says, only somewhat jokingly.
With familial harmony restored, Vitale could direct his attention towards a future that suddenly appeared promising with gravitational discoveries. He and his associates, as members of the LIGO Scientific Collaboration, proclaimed the detection of the initial gravitational wave in February 2016, validating Einstein’s prediction. For Vitale, this achievement also solidified his career mission.
“Had LIGO not discovered gravitational waves when it did, I would not be in my current position,” Vitale asserts. “Certainly, I was very fortunate to be involved at the right time, for me, for the instrument, and for the science.”
A few months later, Vitale joined the MIT faculty as an assistant professor of physics. Currently, as a recently tenured associate professor, he collaborates with his students to examine a wealth of gravitational signals gathered from Advanced LIGO, as well as Virgo (a related detector in Italy) and KAGRA in Japan. The combined capabilities of these observatories allow scientists to identify at least one gravitational wave per week, unveiling a range of extreme sources, from merging black holes to colliding neutron stars.
“Gravitational waves provide us with a unique perspective on the same universe, which could reveal phenomena that are challenging to observe with just photons,” Vitale explains.
Chance encounters
Vitale hails from Reggio di Calabria, a quaint coastal town located in the southern part of Italy, right at “the tip of the boot,” as he describes it. His family owned and operated a nearby grocery store, where he spent so much time in his youth that he could recite the names of nearly all the wines housed there.
At the age of 9, he recalls visiting the local newsstand, which also offered used books. He pooled all his money to purchase two books, both authored by Albert Einstein. One was a compilation of letters from the physicist to his acquaintances and relatives. The other was his theory of relativity.
“I read the letters, and then endeavored through the second book and remember encountering these peculiar symbols that conveyed nothing to me,” Vitale reminisces.
Regardless, the young boy was captivated and continued to delve into physics and later, quantum mechanics. Toward the conclusion of high school, it was uncertain if Vitale could pursue higher education. Large grocery chains had forced his parents’ store to close, resulting in the family losing their home and grappling to reclaim their footing. Yet, with his parents’ encouragement, Vitale applied and was accepted to the University of Bologna, where he achieved a bachelor’s and a master’s in theoretical physics, focusing on general relativity and approximating methods to resolve Einstein’s equations. He subsequently pursued his PhD in theoretical physics at Pierre and Marie Curie University in Paris.
“Then, circumstances changed in a very, very unpredictable manner,” he notes.
Vitale’s PhD advisor was organizing a conference, and Vitale volunteered to distribute badges and flyers and assist attendees in orienting themselves. On that first day, one attendee caught his attention.
“I noticed this gentleman sitting on the floor, somewhat banging his head against his computer because he could not connect his Ubuntu device to the Wi-Fi, which was quite common at that time,” Vitale recalls. “So I attempted to assist him, and failed miserably, but we started conversing.”
The attendee turned out to be a professor from Arizona who specialized in analyzing gravitational-wave signals. Throughout the course of the conference, the two became acquainted, and the professor extended an invitation to Vitale to work with his research group in Arizona. This unexpected chance opened a pathway to gravitational-wave physics that Vitale might have missed otherwise.
“When I engage with undergraduates about how they can aspire to shape their careers, I often express that I am unsure if any specific planning is feasible,” Vitale advises. “The most one can hope for is a chaotic journey that, in the grand scheme, progresses in the right direction.”
High risks, substantial rewards
Vitale spent two months at Embry-Riddle Aeronautical University in Prescott, Arizona, where he dissected simulated data of gravitational waves. At that period, around 2009, no genuine detection of gravitational waves had occurred. The initial version of the LIGO detectors commenced observations in 2002 yet had yielded no results thus far.
“Most of my initial years were dedicated entirely to analyzing simulated data due to the absence of actual data. This led many individuals to exit the field as it was not a clear trajectory,” Vitale explains.
Nonetheless, the work he conducted in Arizona only intensified his interest, prompting Vitale to specialize in gravitational-wave physics, returning to Paris to complete his PhD, and subsequently accepting a postdoctoral position at NIKHEF, the Dutch National Institute for Subatomic Physics at the University of Amsterdam. There, he became an integral member of the Virgo collaboration, forging further connections within the gravitational-wave community.
In 2012, he relocated to Cambridge, Massachusetts, where he began as a postdoc at MIT’s LIGO Laboratory. At that point, scientists there concentrated on fine-tuning Advanced LIGO’s detectors and simulating the types of signals they might capture. Vitale contributed to the development of an algorithm designed to identify signals likely originating from gravitational waves.
Just prior to the detectors being activated for the first observation run, Vitale was elevated to the position of research scientist. And as fortune would have it, he was collaborating with MIT students and colleagues on one of the two algorithms that eventually identified what would later be verified as the inaugural gravitational wave.
“It was exhilarating,” Vitale reflects. “Additionally, it took us several weeks to affirm to ourselves that it was indeed real.”
In the flurry that ensued following the official announcement, Vitale ascended to the rank of assistant professor in MIT’s physics department. In 2017, in acknowledgment of the groundbreaking discovery, the Nobel Prize in Physics was presented to three key members of the LIGO team, including MIT’s Rainier Weiss. Vitale and other members of the LIGO-Virgo collaboration were present at the Nobel ceremony later in Stockholm, Sweden — a moment captured in a picture proudly displayed in Vitale’s office.
In 2022, he received a promotion to associate professor. In addition to examining gravitational-wave signals from LIGO, Virgo, and KAGRA, Vitale is advancing plans for an even larger and more advanced LIGO successor. He is involved in the Cosmic Explorer Project, which seeks to construct a gravitational-wave detector similar in design to LIGO but ten times larger. At that scale, researchers believe such an instrument could capture signals from sources significantly farther away in both space and time, potentially close to the universe’s inception.
Scientists would then be capable of searching for previously undetected sources, such as the earliest black holes formed in the universe. Moreover, they could explore within the same vicinity as LIGO and Virgo, but with heightened precision. This may enable them to observe gravitational signals that Einstein had not anticipated.
“Einstein formulated the theory of relativity to clarify everything from the orbit of Mercury, which circles the sun every 88 days, to objects like black holes that have 30 times the sun’s mass and move at half the speed of light,” Vitale explains. “There’s no justification for expecting the same theory to apply to both scenarios, but thus far, it appears so, and no deviations from relativity have been detected. However, the search must continue. It’s high risk, for substantial gain.”