- 3456 - BLACKHOLES - what are they, really? In December, 2021, telescopes captured evidence of the closest blackhole pair to our own planet, a duo spinning around one another some 89 million light-years away from Earth in the constellation Aquarius.
------------- 3456 - BLACKHOLES - what are they, really?
- February, 2021, discoveries of blackholes, strange gravitational beast, include the fastest spinning blackhole. Physicists revised their estimates of the properties of the cosmic monster sitting in the heart of the Cygnus X-1 system, which also happens to be the first blackhole ever confirmed to exist.
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- Originally discovered nearly 60 years ago, the Cygnus X-1 blackhole was found to be 50% more massive than previously thought, making it 21 times the sun's mass, and spinning very close to the speed of light, setting a new record for blackhole rotation.
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- This blackhole in Cygnus X-1 is located about 7,200 light-years away and is slowly consuming a blue supergiant companion star.
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- When a star wanders too close to the edge of a blackhole, gravitational forces will pull it apart into long strands that get sucked down the blackhole. This process, known as "spaghettification," produces light as the stellar material heats up via friction, allowing astronomers to capture the act.
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- In May, 2021, researchers for the first time spotted a star being shredded and devoured in this way by a blackhole weighing 30,000,000 times the mass of the sun and located in the center of a galaxy 750 million light-years from Earth. In addition to capturing important data about spaghettification, the observations helped scientists create an incredible visualization of the stellar ingestion.
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- In June, 2021, researchers with the Laser Interferometer Gravitational-Wave Observatory (LIGO) watched two gigantic blackholes merge into a single entity and analyzed the ripples in the fabric of space-time called gravitational waves created as the blackholes spiraled toward each other at high speed.
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- They found that the resulting blackhole's surface area was larger than the first two combined. In addition to providing amazing data, the findings help prove a 1971 conjecture from British astrophysicist Stephen Hawking known as the blackhole area theorem.
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- The theorem states that it is impossible for the surface area of a blackhole to decrease over time, a law Hawking derived using both Einstein's theory of general relativity as well as his understanding of entropy. According to quantum mechanics, blackholes should be able to shrink and evaporate, and so it's unclear how to square that with Hawking's law that their surface area must also always increase.
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- LIGO had several blackhole findings to deliver in June, when researchers had seen blackholes merging with compact entities called neutron stars. Along with blackholes, neutron stars are one potential end result of a massive star's death, when the star explodes as a supernova and leaves behind a remnant.
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- While LIGO had previously seen hints of potential blackhole-neutron star mergers, it wasn't until this year that two signals conclusively proved such mergers were happening. Both detections occurred in January, 2020, roughly 10 days apart.
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- The first involved a blackhole with about six times the sun's mass devouring a neutron star one and a half times the sun's mass, while the second involved a blackhole about nine times the mass of the sun and a neutron star about twice as massive as the sun.
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- Almost every known galaxy has a supermassive blackhole in its center, suggesting that there is a tight relationship between the two entities. But scientists still don't understand how a blackhole affects its galactic host.
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- Research released in June, 2021, showed high-speed winds being blown from a 13 billion-year-old galaxy, one nearly as old as the universe itself. This is the earliest detected example of galactic wind, which is burped out of supermassive blackholes as they consume surrounding gas and dust.
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- The powerful winds traveling at roughly 1.1 million mph move fast enough to propel material all over the galaxy and likely hinder star formation. This suggests that galaxies and their blackholes have an ancient and very tight bond.
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- In July, 2021, astronomers captured X-rays flaring from a supermassive blackhole in the center of a spiral galaxy called “Zwicky“, which is 1.8 billion light-years away. The researchers not only detected light coming from the front of the blackhole, but they also managed to find strange echoes of light that they initially couldn't place.
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- These turned out to originate from the back of the blackhole, meaning that the mammoth entity was warping the fabric of space-time so much that light was being pulled from one side of the black hole to the other. This process is exactly what would be expected from Einstein's theory of general relativity but, until now, hadn't been definitively detected.
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- Roughly 12 enormous invisible blackholes could be lurking on the outskirts of the Milky Way. In August, 2021, researchers released results from a new simulation of galaxy collisions. During such monumental events, gravitational forces could cause supermassive blackholes, weighing millions or billions of times that of the sun, to go flying and wander the inky depths of the cosmos.
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- Some of these may subsequently settle in the halos of galaxies like our own, with a Milky-Way-size galaxy expected to host about 12 on average
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- The previous record-holding blackhole pair is located five times farther away than this one, meaning scientists have the opportunity to study such systems in greater detail than before. The larger has a mass of almost 154 million suns, while the smaller is 6.3 million times more massive than our star. They orbit one another with a separation of a mere 1,600 light-years indicating that they will merge into one giant blackhole 250 million years from now.
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- A tiny galaxy orbiting our own at a distance of about 820,000 light-years appears to contain an oddity. The “Leo I dwarf galaxy“, which is 50 times smaller than the Milky Way, hosts an outsized blackhole, one with almost the same mass as the blackhole in the Milky Way's center.
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- Astronomers are baffled as to how such a large blackhole came to reside in such a small galaxy. There is no explanation for this kind of blackhole in dwarf spheroidal galaxies.
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- OK, we have found all these blackholes. So what happens if you go inside one? What could possibly await you should you somehow survive? Where would you end up?
- The mysteries of blackholes run deep. Once someone falls past the event horizon, nobody could ever send a message back. They'd be ripped to pieces by the enormous gravity.
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- Ever since Albert Einstein's general theory of relativity was considered to have predicted blackholes by linking space-time with the action of gravity, it has been known that blackholes result from the death of a massive star leaving behind a small, dense remnant core.
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- Assuming this core has more than roughly three times the mass of the sun, gravity would overwhelm to such a degree that it would fall in on itself into a single point, or “singularity“, understood to be the blackhole's infinitely dense core.
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- The resulting uninhabitable blackhole would have such a powerful gravitational pull that not even light could avoid it. The “event horizon” is the point at which light and matter can only pass inward there is no escape. Tidal forces would reduce your body into strands of atoms, 'spaghettification', and the object would eventually end up crushed at the singularity.
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- Scientists have looked into the possibility that blackholes could be “wormholes” to other galaxies, or, a path to another universe.
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- The theory suggests that anything which goes beyond the event horizon is simply added to the blackhole and because time distorts close to this boundary, this will appear to take place incredibly slowly. An observer far away will not see their astronaut friend fall into the blackhole. They'll just get redder and fainter as they approach the event horizon, as a result of gravitational red shift. But the friend falls right in, to a place beyond 'forever.'
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- If wormholes exist, they might lead to another universe. But, there's no evidence that wormholes are real or that a blackhole would act like one. If blackholes do lead to another part of a galaxy or another universe, there would need to be something opposite to them on the other side.
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- Could this be a white hole? A blackhole links to a whitehole that exists in the past. Unlike a blackhole, a whitehole will allow light and matter to leave, but light and matter will not be able to enter.
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- Scientists have continued to explore the potential connection between black and white holes. There is a classic metric satisfying the Einstein equations outside a finite space-time region where matter collapses into a blackhole and then emerges from a whitehole. All of the material blackholes have swallowed could be spewed out, and blackholes may become whiteholes when they die.
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- Far from destroying the information that it absorbs, the collapse of a blackhole would be halted. It would instead experience a quantum bounce, allowing information to escape.
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- Hawking said a blackhole doesn't last forever. Hawking calculated that the radiation would cause a blackhole to lose energy, shrink and disappear. Given his claims that the radiation emitted would be random and contain no information about what had fallen in, the blackhole, upon its explosion, would erase loads of information.
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- This meant Hawking's idea was at odds with quantum theory, which says information can't be destroyed. Physics states information just becomes more difficult to find because, should it become lost, it becomes impossible to know the past or the future.
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- Do we go back to the concept of blackholes emitting preserved information and throwing it back out via a whitehole? Applying “loop quantum gravity” to a blackhole finds that gravity increased towards the core but reduced and sent whatever was entering into another region of the universe. The results gave extra credence to the idea of blackholes serving as a portal.
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- In this scenario singularity does not exist, and so it doesn't form an impenetrable barrier that ends up crushing whatever it encounters. It also means that information doesn't disappear.
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- A theory known as the “AMPS firewall“, or the “blackhole firewall hypothesis” has calculations in quantum mechanics that turn the event horizon into a giant wall of fire and anything coming into contact would burn in an instant. In that sense, blackholes lead nowhere because nothing could ever get inside.
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- This too violates Einstein's general theory of relativity. Someone crossing the event horizon shouldn't actually feel any great hardship because an object would be in free fall and, based on the equivalence principle, that object, or person, would not feel the extreme effects of gravity.
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- It could follow the laws of physics present elsewhere in the universe, but even if it didn't go against Einstein's principle it would undermine quantum field theory or suggest information can be lost.
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- The gravitational collapse would produce an 'apparent horizon' instead. This horizon would suspend light rays trying to move away from the core of the blackhole, and would persist for a "period of time."
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- Apparent horizons temporarily retain matter and energy before dissolving and releasing them later down the line. This explanation best fits with quantum theory which says information can't be destroyed, and, if it was ever proven, it suggests that anything could escape from a black hole.
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- Hawking went as far as saying blackholes may not even exist. Blackholes should be redefined as “metastable bound states” of the gravitational field. There would be no singularity, and while the apparent field would move inwards due to gravity, it would never reach the center and be consolidated within a dense mass.
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- This particular mystery is going to swallow up many more scientific hours for a long time to come.
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- A component of dark matter could be formed by remnants of evaporated blackholes, and Hawking's paper on blackholes and 'soft hair' was released in 2018, and describes how zero-energy particles are left around the point of no return, the event horizon, an idea that suggests information is not lost but captured.
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- This flew in the face of the “no-hair theorem” which was expressed by physicist John Archibald Wheeler and worked on the basis that two blackholes would be indistinguishable to an observer because none of the special particle physics pseudo-charges would be conserved.
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- It's an idea that has got scientists talking, but there is some way to go before it's seen as the answer for where blackholes lead. If only we could find a way to leap into one. You can do it . I will watch.
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February 10, 2022 BLACKHOLES - what are they , really? 3456
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