Monster black hole found in tiny galaxy

Discovery hints at twice as many supermassive black holes in the nearby Universe as previously thought.

Astronomers have for the first time found strong evidence for a giant black hole in a Lilliputian galaxy. The finding suggests that supermassive black holes could be twice as numerous in the nearby Universe as previously estimated, with many of them hidden at the centres of small, seemingly nondescript galaxies known as ultra-compact dwarfs.

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Oceanic Black Holes Found in Southern Atlantic

Black holes are a tear in the fabric of space-time from which nothing escapes, not even light. They take on a mythic significance in popular culture as portals to alternate dimensions or grave threats to space travel. Astronomers are certain they exist out there in the universe, formed by the collapse of dead stars.

Now, physicists have found mathematical analogs to black holes here on Earth, specifically in the southern Atlantic Ocean where eddies whirl about. The work was posted to arXiv and reported first by the The Physics arXiv Blog.

The scientists describe the eddies using Edgar Allan Poe’s “A Descent into the Maelström”:

“The edge of the whirl was represented by a broad belt of gleaming spray; but no particle of this slipped into the mouth of the terrific funnel…”

That’s exactly how eddies look, the study says. A belt of spray encircles the whirlpool but the liquid does not fall in.

Similarly, black holes in space are encircled by photon (light) spheres, a region where the gravity is so strong (because of the density of the black hole) that it causes light to travel in an orbit. And there the photons remain, in precarious balance, neither falling into the hole or escaping. That’s similar to Poe’s description of the belt of spray around the Maelström.

And much like astronomical black holes, oceanic eddies exhibit singularity.

To locate these oceanic black holes, the scientists examined satellite images of the Agulhas Current in the Indian Ocean. The current travels along the east coast of Africa before turning back on itself in a loop. The loop occasionally pinches off and forms eddies that whirl off into the South Atlantic Ocean, remaining intact for more than three months.

The eddies are a coherent island of water in an otherwise turbulent ocean. As such, they “create moving oases for the marine food chain or even impact climate change through their long-range transport of salinity and temperature,” the study states. The eddies will capture any detritus floating nearby and swallow it, thereby transporting oil and garbage. And nothing within leaks out.

From Poe’s story again, a description of the his fictional Maelström:

“…whose interior, as far as the eye could fathom it, was a smooth, shining, and jet-black wall of water, inclined to the horizon at an angle of some forty-five degrees, speeding dizzily round and round with a swaying and sweltering motion, and sending forth to the winds an appalling voice, half shriek, half roar, such as not even the mighty cataract of Niagara ever lifts up in its agony to Heaven.”

via DNews

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Journey into a Schwarzschild black hole.

The simplest kind of black hole is a Schwarzschild black hole, which has mass yet no electric charge or spin. This black hole geometry was discovered by Karl Schwarzschild in 1915, shortly after Einstein presented his final theory of General Relativity. The gifs above are created from a simulation depicting what you would theoretically see if you traveled towards a black hole, against a panorama of our Milky Way.

First of all, as you approach, you clearly see gravitational lensing taking place, with the black hole bending light around it. It appears to ‘repel’ the Milky Way radially, which then stretches the image transversely. The sections closer to the black hole experience greater ‘repulsion’, so the image appears to be compressed radially.

You then take note of the Einstein Ring seen around the black hole, occurring because of the bright objects lying directly behind it. Due to the aforementioned gravitational lensing, the light from these bright objects is bent around the black hole and forms this ring.

Fortunately (or maybe unfortunately), as you get closer, the trajectory of your journey does not have enough angular momentum to go into an unstable circular orbit. If you had slightly more, you would find yourself orbiting this black hole, which would, in fact, make for a fairly nice view. However, you carry on travelling towards the center.

Next, you swiftly pass through the photon sphere,where light rays can orbit the black hole in unstable circular orbits. However, you do not see anything of particular interest, but are more concerned with your forthcoming fall through the horizon. 

As you travel, you would not know at what point you fell through the black hole’s horizon. However, as you do pass through it unaware, it apparently splits in two, explained nicely by these Penrose diagrams (if you have the chance to give them a quick glance over whilst you’re hurtling towards your inevitable death). Here, space is falling faster than light, meaning you are carried inexorably inward.

Anyone who happens to be watching your spectacular journey would see you as fairly dim and red. This effect is due to red shift, with anything falling past the black hole’s horizon appearing this way to an observer outside of this point.

As you get closer and closer to the center, the black hole’s tidal forces begin to wear on you. Presuming you are travelling feet first, you feel a greater force of gravity in your lower half than up by your head. Due to these forces, you are stretched vertically and crushed horizontally; this is known as spaghettification. These forces also mean that your view of the Universe beyond is blue shifted and bright around your waist, but red shifted and dim above that; a strange sight.

Despite having been utterly torn apart from the tidal forces, a tenth of a second later you reach the black hole’s singularity, the center point of infinite curvature. Here, space and time as you know them come to an end, and so does your exciting journey.

It must be remembered that real black holes are probably much more complicated than Schwarzschild black holes; they likely spin and are not isolated, so a journey into a normal black hole could be slightly different adventure.

Credits: 

http://jila.colorado.edu/~ajsh/insidebh/schw.html

http://galaxy.phy.cmich.edu/~axel/mwpan2/krpano/

Finally! A black hole that you can visit and survive!

Want a trip through a black hole without having to experience that pesky death? You’re in luck. There’s a special kind of black hole that’s not just survivable, but might get you to another time, or another universe.

Black holes are, traditionally, the scariest things in the universe. Huge, mysterious, inescapable, they wander through the universe and eat everything that gets too close. “Too close” is defined by their event horizon. This is the point at which they go dark, because it requires so much energy to escape them that not even light can get away. Since not even a photon can cross the barrier, no event that happens inside the horizon can ever have an effect on people outside.

Unless, something very odd was going on in the center of the black hole. Most black holes spin - this is something that was discovered way back in the 1960s by physicist Roy Kerr. It wasn’t exactly a shock, because most of the material that collapses into a black hole was already spinning. Sometimes, however, the spin on Kerr black holes goes a little above and beyond. Ever spun a glass of water, or soda bottle, so that the liquid inside swirls? Sometimes, if you spin it enough, the liquid actually parts, leaving a clear center and a spinning ring of water around it. The same kind of thing can happen in Kerr black holes. Instead of a singularity at the center, there’s a ring. And you can go through the open portion of that ring without touching the gravitational crush.

What’s on the other side? A lot of people have wondered. Some people think that these kind of black holes might be our key to time travel. They might be wormholes that let us hop between different points of the universe. Or they might be portals to different universes entirely. First we’ll have to find a few, and then we’ll need a few volunteers to go through. Preferably ones that haven’t seen Event Horizon.

Top Image: NASA/JPL-Caltech

Second Image: Dana Berry/NASA

Via NASAAstrophysics SpectatorDiscovery.

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An Introduction to Black Holes.

Defined as “A dense, compact object whose gravitational pull is so strong that - within a certain distance of it - nothing can escape, not even light. Black holes are thought to result from the collapse of certain very massive stars at the ends of their evolution.”

Learn more about black holes here, and here. View images of black holes here.

The Super Massive Black Hole of Sagittarius A*

Astronomers using Herschel have spotted a cloud of incredibly hot gas very close to the supermassive black hole that lies at the heart of our Milky Way galaxy.

The supermassive black hole goes by the name of Sagittarius A*, and weighs in at 4 million times the mass of our Sun. It is nearly 30,000 light years away at the very centre of our galaxy, but is still hundreds of times closer than other such black holes, which are usually found at the centres of large galaxies.

Its relative proximity makes it the ideal target for studying these extreme environments in detail, though our view is often obscured by dense clouds of dust draped throughout the Milky Way. By studying it in far-infrared light, Herschel can see through this dust and examine the surroundings of the black hole itself. The black hole is surrounded by a ring of gas around 30 light years across, but right in the centre is a mini spiral of gas flowing inwards.

Herschel observations taken in 2011 and 2012 allowed astronomers to examine the region within around a light year of the black hole itself. The data showed the presence of elements such as carbon, nitrogen and oxygen, as well as simple molecules including water, carbon monoxide and hydrogen cyanide.

When a star meets a black hole.

Supermassive black holes lurk at the centre of almost every galaxy, weighing billions of times more than our Sun - and Nasa has just caught sight of one ‘feeding’ on a star. A re giant star that wandered too close to the centre of a galaxy 2.7 billion light years away was pulled in by the enormous gravity of the black hole - and shredded.

Are White Holes Real?

Sailors have their krakens and their sea serpents. Physicists have white holes: cosmic creatures that straddle the line between tall tale and reality. Yet to be seen in the wild, white holes may be only mathematical monsters. But new research suggests that, if a speculative theory called loop quantum gravity is right, white holes could be real—and we might have already observed them.

A white whole is, roughly speaking, the opposite of a black hole. “A black hole is a place where you can go in but you can never escape; a white hole is a place where you can leave but you can never go back,” says Caltech physicist Sean Carroll. “Otherwise, [both share] exactly the same mathematics, exactly the same geometry.” That boils down to a few essential features: a singularity, where mass is squeezed into a point of infinite density, and an event horizon, the invisible “point of no return” first described mathematically by the German physicist Karl Schwarzschild in 1916. For a black hole, the event horizon represents a one-way entrance; for a white hole, it’s exit-only.

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BLACK BODY SPECTRUM

This is a place of too much gravity. Fall into the black hole: see nothing, feel nothing. Only listen to that hollow heartbeat as you get closer to the event horizon — nothing here screams louder than the bass.

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Turbulent Black Holes Grow Fractal Skins As They Feed

Feeding black holes develop a fractal skin as they grow. That’s the conclusion of simulations that take advantage of a correlation between fluid dynamics and gravity.

"We showed that when you throw stuff into a black hole, the surface of the black hole responds like a fluid – and in particular, it can become turbulent," says Allan Adams at the Massachusetts Institute of Technology. "More precisely, the horizon itself becomes a fractal."

Fractals are mathematical sets that show self-similar patterns: zoom in on one part of a fractal drawing, like the famous Mandelbrot set, and the smaller portion will look nearly the same as the original image. Objects with fractal geometries show up all over nature, from clouds to the coast of England.

Adams and his colleagues have now found evidence that fractal behaviour occurs in an unexpected place: on the surface of a feeding black hole. Black holes grow by devouring matter that falls into them; the black hole at the centre of our galaxy is due to feast on a gas cloud later this year. But the details of how feeding black holes grow, and how this might affect their host galaxies, are still unknown.

Redefining Black Holes

According to Stephen Hawking, we’ve got black holes all wrong

As far as we are concerned, a black hole is a structure in space with an event horizon past which no light or matter can escape and ends up being devoured. Hawking is proposing that instead of having a clear ‘event horizon’, black holes actually have an ‘apparent horizon' which constantly fluctuates due to quantum effects. 

One of the nifty consequences of this theorised model is that it resolves the firewall paradox which can be easily explained by considering an unfortunate astronaut falling into the event horizon of a black hole (RIP Mr. Astro).

Classical physics tells us that this poor soul would be stretched out and spaghettified (yes, this is a real word) until being crushed at the infinitely dense core. Quantum theory, however, suggests that the event horizon of a black hole would be a highly energetic reason and would act as a ‘firewall’ causing the astronaut to be burned to a crisp.

This is a big problem because it violates the equivalence principle which tells us that free falling is indistinguishable from floating in empty space (which obviously is not the case if find yourself being burned to a crisp). Another solution to the paradox suggests that information is simply lost in a black hole,  but this is also very controversial as it violates unitarity

Apparently, Hawking’s paper resolves this paradox. By replacing the event horizon with an apparent horizon, the theorised firewall can no longer exist as there is no uniform boundary to the black hole. However, the paper consists of just two pages with no calculations so it is very difficult for anyone to draw any definite conclusions. Some theorists have suggested that this theory could raise even more radical issues than the existence of firewalls. 

If Hawking’s past discoveries are anything to go by, this could turn into a very interesting debate. 

Falling Into a Black Hole

A gas cloud named G2 is about to collide with Sagittarius A*, the supermassive black hole at the center of our galaxy. A simulation shows how the cloud might be stretched and torn apart.

Black holes, the ultradense collapsed objects predicted by Einstein’s theory of general relativity, are often depicted as voracious feeders whose extraordinary gravity acts like a one-way membrane: Everything is sucked in, even light, and virtually nothing leaks out.

Now, for the first time, astronomers may have a chance to watch as a giant black hole consumes a cosmic snack.

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Could Tiny ‘Black Hole Atoms’ Be Elusive Dark Matter?

Dark matter, the invisible and mysterious stuff that makes up most of the material universe, might be hiding itself in microscopic black holes, says a team of Russian astrophysicists.

No one knows what dark matter is. But scientists do know that it must exist, because there is not enough visible matter in the cosmos to account for all the gravity that binds galaxies and other large-scale structures together.

Astronomers have been on the hunt for dark matter for decades now, using detectors both on Earth and in space. The new hypothesis, formulated by astrophysicists Vyacheslav Dokuchaev and Yury Eroshenko at the Institute for Nuclear Research of the Russian Academy of Sciences in Moscow, suggests that dark matter could be made of microscopic — or quantum — “black hole atoms.”

The concept is not entirely new; others have suggested that various types of miniature black holes could make up dark matter, which is so named because it apparently neither absorbs nor emits light, and thus cannot be detected directly by telescopes.

Physicists have also long believed that microscopic black holes must have existed in the early universe, because quantum fluctuations in the density of matter just after the Big Bang would have created regions of space dense enough to allow the formation of such tiny black holes.

Some researchers believe that the universe could still be full of such “primordial black holes.”

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