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Cases of Black Hole Mistaken Identity. Gravity is constant across the event horizon. The inner region of a black hole, where the object's mass lies, is known as its singularity , the single point in space-time where the mass of the black hole is concentrated.
Scientists can't see black holes the way they can see stars and other objects in space. Instead, astronomers must rely on detecting the radiation black holes emit as dust and gas are drawn into the dense creatures. But supermassive black holes, lying in the center of a galaxy, may become shrouded by the thick dust and gas around them, which can block the telltale emissions. Sometimes, as matter is drawn toward a black hole, it ricochets off the event horizon and is hurled outward, rather than being tugged into the maw.
Bright jets of material traveling at near-relativistic speeds are created. Although the black hole remains unseen, these powerful jets can be viewed from great distances.
The Event Horizon Telescope's image of a black hole in M87 released in was an extraordinary effort, requiring two years of research even after the images were taken. That's because the collaboration of telescopes, which stretches across many observatories worldwide, produces an astounding amount of data that is too large to transfer by internet.
With time, researchers expect to image other black holes and build up a repository of what the objects look like. LIGO's observations also provide insights about the direction a black hole spins. As two black holes spiral around one another, they can spin in the same direction or in the opposite direction. There are two theories on how binary black holes form.
Moreover, once LIGO turned on and immediately started hearing these sorts of objects merge with each other, astrophysicists realized that there must be more black holes lurking out there than they had thought. Maybe a lot more. The discovery of these strange specimens breathed new life into an old idea — one that had, in recent years, been relegated to the fringe. We know that dying stars can make black holes.
But perhaps black holes were also born during the Big Bang itself. After all, no dark matter particle has shown itself, despite decades of searching. What if the ingredients we really needed — black holes — were under our noses the whole time? He calculated that if the baby universe spawned enough black holes to account for dark matter, then over time, these black holes would settle into binary pairs, orbit each other closer and closer, and merge at rates thousands of times higher than what LIGO observes.
He urged other researchers to continue to investigate the idea using alternate approaches. But many lost hope. The argument was so damning that Kamionkowski said it quenched his own interest in the hypothesis. Now, however, following a flurry of recent papers, the primordial black hole idea appears to have come back to life. In one of the latest, published last week in the Journal of Cosmology and Astroparticle Physics , Karsten Jedamzik , a cosmologist at the University of Montpellier, showed how a large population of primordial black holes could result in collisions that perfectly match what LIGO observes.
T he original idea dates back to the s with the work of Stephen Hawking and Bernard Carr. Each of these regions would collapse into a black hole. More progress came in the s. By then, theorists also had the theory of cosmic inflation, which holds that the universe experienced a burst of extreme expansion right after the Big Bang.
Inflation could explain where the initial density fluctuations would have come from. On top of those density fluctuations, physicists also considered a key transition that would coax along the collapse.
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