The Sound of Two Black Holes Colliding Is Music to Szabolcs Marka’s Ears
“It was life-changing in the way that the world started to share our vision. The world started to believe with us.”
Image: Electra Sinclair
On September 14, 2015, Szabolcs Marka woke up to an email he couldn't believe. In fact, he refused to believe it. Living close to the Columbia University campus, where he is a professor of physics, he headed to the Pupin Physics Laboratories to see for himself. While the rest of his team stared in shock or started to celebrate, Marka decided to wait for more data.
But the information kept pouring in—and it all said the same thing. They'd done it. For the first time ever, they'd observed gravitational waves.
The Laser Interferometer Gravitational-Wave Observatory (LIGO) team, of which Szabolcs is a member, felt vindicated. They made the announcement on February 11, 2016: they'd been able to prove Einstein's 100-year-old general theory of relativity, about incredible disturbances in the cosmos causing a ripple (or a gravitational wave) in the fabric of space-time. LIGO was thrust into the international spotlight, and the observation was heralded as one of the most important in the world, equal to the Higgs boson particle discovery.
They'd felt the merging of two black holes, each more than 30 times the mass of the Sun, distorting space-time
"Up until that point, we had an uphill battle to prove that our science and our dreams and our vision makes sense," Marka told me recently. LIGO, created with the goal of finding gravitational waves, had been searching since 2002. "It was life-changing in the way that the world started to share our vision. The world started to believe with us."
What the LIGO team had actually done was detect the gravitational waves of a binary black hole—they'd felt the merging of two black holes, each more than 30 times the mass of the Sun, distorting space-time from billions of light years away. They'd obviously known, before this point, that black holes existed. Others had even seen the (literal) light and gathered information about binary pulsars (winning a Nobel Prize in 1993).
But sometimes, just one source isn't enough—we need complimentary messengers, especially because light is a secondhand source of information, Marka explained.
Think of lightning and thunder: while they're linked, each provides a unique set of information. To calculate your distance from the storm, you rely on the time lapse between the flash of light, and the clap of thunder. The merging of black holes is the storm of galaxies. Scientists had already seen the lights of the cosmos, but thanks to the 2015 observation, Marka explained, "we started to hear the cosmos."
Marka was born in a small town in Ukraine and moved to the United States to get his PhD from Vanderbilt University. He bounced around (Cornell, Caltech, particle physics, nuclear physics) before landing at Columbia in 2004, in pursuit of astrophysics.
"I wanted to have ... research that's high risk and high gain," he told me. LIGO was high risk. Early work on detection with laser interferometers had begun in the '70s, and LIGO was operational since 2002, but even by 2010 they hadn't detected anything.
By the time Marka joined in 1999, people called him crazy. "Many physicists claimed that [LIGO] would never work," he said. "That's what I needed. I wanted to invest my life in something which makes a difference."
"You can actually encode the sound of gravitational waves in MP3 if you wish and have a ringtone on your phone"
With no results for almost half a century, in 2015, an upgraded version of LIGO began collecting data. The fundamentals were still the same—in the two locations in Louisiana and Washington, L-shaped laser interferometer observatories waited for a sign. Basically, mirrors at the end of 4-kilometer long (2.5-mile) vacuum arms reflected lasers back at each other, waiting for a ripple. If one observatory detected anything, the other had to corroborate the anomaly.
"This is the most expensive, biggest 'nothing' on Earth. We have 16 kilometers of the best vacuum we can make," Marka explained. One of the challenges for LIGO was isolating the—let's just say very very very faint—waves of noise from black holes, differentiating it from the sound of cars, or people's voices, or even the flicker of a burning candle.
Once they did detect gravitational waves, I asked Marka, what did it sound like?
He whooped. "It's a chirp," he explained. "You can actually encode it in MP3 if you wish and have a ringtone on your phone."
When I spoke to Marka, more than a year had passed since the LIGO announcement (since then, they've observed a second binary black hole). He was sitting in Riverside Park, not too far from the university campus. With the distant hum of cars and a dog barking in the background, he told me about the latest from LIGO.
"We are making the detector better," he said, adding that they're also working on data analysis, as well as the IceCube collaboration, a neutrino detector at the South Pole.
But his recent interest is biophysics, he explained. "I did a computation and the chance that I will die by binary black holes is very small." Neurodegenerative diseases and cancer are more likely to claim him, he continued, so technological advancements that are important for public health now have a bigger moral pull.
Ultimately, both are equally as important to Marka. Scientific discoveries either save lives, he told me, or like art, "they make lives better."
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