Astrophysicists have seen the strangest. gravitational wave Still a sign, an observation that could compel scientists to rewrite what they know about the cosmos.
Gravitational waves are formed when massive objects distort the space-time that surrounds them and send waves throughout the universe. Scientists caught the first detection of such waves, formed by two colliding black holes, in 2015.
Since then, gravitational wave detections have only gotten weirder, and scientists have only gotten more excited. Now, a group of researchers has announced the first detection of a gravitational wave signal created by a collision involving an object larger than the largest known. neutron star but smaller than the smallest known dungeon. Although detection is too complicated for scientists to hope to pinpoint what happened, the signal raises hopes that more strange observations will arrive. This detection could even herald a new understanding of how massive stellar explosions called supernovae occur.
“It is a fantastic event, it will really change the way we understand black hole formation and neutron stars,” Christopher Berry, a gravitational wave astronomer at Northwestern University and co-author of the new research, told Space.com. “It will remain a mystery until we can get more observations, but that does not mean it is not informative.”
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“We are very confident in the results, this is a really beautiful sign,” he said. “It’s a wonderful, clean sound if you look at the data. I couldn’t believe it the first time I saw it, it’s impressive.”
Scientists caught the gravitational wave, or “screech,” on August 14, 2019, and were even more intrigued when initial analysis suggested that the collision may have fused a black hole and a neutron star. The collision of those two objects is a type of gravitational wave event that scientists have been eagerly awaiting, as they have so far only seen mergers of matched pairs.
But as astrophysicists did more analysis on the data, they realized they were looking at something even stranger. According to the scientists’ analysis of the fusion event, one of the objects that collided was approximately 23 times the mass of our sun, which is a black hole, and the other approximately 2.6 times the mass of our sun, that is .. . Well, that is something.
Mystery of the mass gap
This size falls into what scientists call the mass gap: an object significantly smaller than any black hole studied to date (approximately 5 times the mass of the sun), but also probably larger than any known neutron star (approximately 2.5 times the mass of Dom).
“Mixed-nature mergers (black holes and neutron stars) have been predicted for decades, but this compact object in the mass gap is a complete surprise,” said co-author Vicky Kalogera, astrophysicist at Northwestern University, he said in a statement. “Although we cannot classify the object with conviction, we have seen the heaviest known neutron star or the lightest known black hole. Either way, it breaks a record.”
In other circumstances, scientists may have been able to determine what the object actually was prior to the collision that created the observable screech. But fate did not cooperate here. The scientists did not detect any light signals that a neutron star could have produced, but that does not rule out that it could have been a neutron star.
And unlike the generally well-matched collisions Scientists have studied to date, this pair is highly uneven, with the largest object containing about nine times the mass of the smallest, making it even more difficult for scientists to see details of the event in the gravitational wave chirp. . “I think of Pac-Man eating a small point,” Kalogera said in the statement. “When the masses are highly asymmetric, the smallest black object can be eaten by the black hole in one bite.”
The event was also difficult to study because it was quite far away. The collision appears to have occurred about 800 million light-years away from Earth; by context, that’s about six times more distant than the neutron star’s binary fusion detected in August 2017 by its flash of light.
Due to these challenges, to truly decipher the mystery of the cosmic mass gap, scientists will need to observe more of these bordering objects in more collisions, preferably collisions that are not as complicated to analyze. “A binary with a more equal mass would be great, a closer one even better,” Berry said.
And fixing the blurred kingdom between neutron star and black hole Berry said it is not important just for the sake of precision: it will change our understanding of the universe around us.
For one, it will inform scientists about how neutron stars work, which Berry called “the last particle colliders.” “Stellar neutron matter is very difficult to model,” he said. “It is nothing we can simulate here on Earth, the conditions are too extreme.” But the properties of that matter will determine the maximum size of a neutron star, the point at which a large neutron star becomes too large and collapses, the limit that observations like this new research will help determine.
And understanding the mass gap (or lack thereof) would affect astrophysics far beyond these observations, Berry said. For decades, astrophysics Models have assumed that there is a gap between the largest neutron stars and the smallest black holes. If that gap turns out to be significantly smaller than previously assumed, or non-existent, those models will have to be adjusted. Those modified models could change our understanding of the universe more broadly than the definition of mass gap itself, Berry said.
However, the mystery of the mass gap unfolds, this new signal points to the rich future of gravitational wave observations, Berry said.
“This is a testament to the fact that we are just beginning to explore the universe with gravitational waves“, said.” We don’t know what’s out there. We have looked at some of the most common sources now, we know what are the typical types of gravitational waves. But all the complexity, what are the rare beasts in the jungle, we’re still trying to figure it out. “
The research is described in a paper published today (June 23) in Astrophysical Journal Letters.
Email Meghan Bartels at [email protected] or follow her @meghanbartels. Follow us On twitter @Spacedotcom and in Facebook.
