A Finding of 35 New Gravitational Waves Offers ‘Game‑Changing’ Clues About the Universe
A new space discovery has astronomers saying it’s raining gravitational waves. Researchers recently detected a record number of gravitational waves in five months, in a discovery that offers a “new window into the universe.” The fascination is infectious: some likened it to a “tsunami,” others called it a veritable “haul.”
To put things into perspective: the first gravitational wave was detected in 2015 in a massive astrophysical discovery (one of the biggest in the past century) that proved Einstein right. A record of gravitational waves detected from black holes colliding confirmed his theory of relativity. It was a “life-affirming moment,” as a colleague called it. For good reason: it deepened our understanding of the universe in a way unlike any before, and also paved a way for studying it.
“We’re actually hearing them go thump in the night,” Matthew Evans, an assistant professor of physics at MIT, said back then. “We’re getting a signal which arrives at Earth, and we can put it on a speaker, and we can hear these black holes go, ‘Whoop.’ You’re really listening to these things which before were somehow fantastic.”
Now, scientists have recorded 35 new gravitational waves, bringing the tally up to 90. “Gravitational waves are ripples in the fabric of spacetime, created by massive cosmic events – such as pairs of black holes smashing together – up to billions of light-years away,” The Guardian explained. In other words, gravitational waves show collisions of invisible things, such as black hole mergers, sending ripples like those in a pond.
“Information from the black hole masses and spins … gives us a lot of information about how the structure of the universe formed,” Susan Scott, of the Australian National University, and a collaborator in this research, said.
In this case, 32 out of the 35 were a result of pairs of black holes merging into one other. This is no simple feat: imagine two huge pairs of black holes encircling each other – one pair was 145 times as heavy as the mass of the sun, and the other 112 times. “By looking at how a black hole is spinning, for example – how fast it’s spinning, versus … which way it’s pointed – can tell us more about how it came to be: whether these black holes lived their lives apart and met at some point or whether they were stars, to begin with, and then collapsed down [separately] to form black holes,” researcher Shanika Galaudage said. If one ever wondered what happened when two black holes collided, the answer is right here.
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Two other recorded waves were caused by a black hole swallowing a neutron star (tiny, incredibly dense objects). It was only in June that scientists first discovered a black hole colliding with a neutron star.
“Neutron stars merging with black holes are amongst the most extreme phenomena in the Universe,” researchers said in a statement then. “Observing these collisions opens up new avenues to learn about fundamental physics, as well as how stars are born, live, and die.”
It is all about the fundamentals. The gravitational waves offer a game-changing “new window into the universe,” Galaudage said. Scrutinizing the characteristics and circumstances of these collisions will help scientists determine how they were formed.
The paper is yet to be peer-reviewed, but scientists are excited about the ways the detection can widen the understanding of the universe. Next up is detecting the gravitational waves from stars as they become supernovae. “This would help us to understand the process of stars when they finish their life cycle and run out of fuel and blow up and then collapse,” Scott said.
What’s making these detections possible is the upgrades in the instruments. As the detectors become even more sensitive, the researchers will be able to see black hole pairs “coming together throughout the whole universe.”
Gravitational-wave astronomer Maya Fishbach from Northwestern University said while referring to another discovery: “With future gravitational wave data, we will have the statistics to answer these questions, and ultimately learn how the most extreme objects in our Universe are made.”