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.

No one knew exactly what a black hole would look like until they actually built one. Light, temporarily trapped around the black hole, produced an unexpectedly complex fingerprint pattern near the black hole’s shadow. And the glowing accretion disk appeared above the black hole, below the black hole, and in front of it. “I never expected that,” Thorne says. “Eugénie just did the simulations and said, ‘Hey, this is what I got.’ It was just amazing.”

In the end, Nolan got elegant images that advance the story. Thorne got a movie that teaches a mass audience some real, accurate science. But he also got something he didn’t expect: a scientific discovery. 

MORE: Wrinkles in Spacetime: The Warped Astrophysics of Interstellar 

Black holes aren’t black

They’re very dark, sure, but they aren’t black. They glow, slightly, giving off light across the whole spectrum, including visible light.

This radiation is called “Hawking radiation”, after the former Lucasian Professor of Mathematics at Cambridge University Stephen Hawking, who first proposed its existence. Because they are constantly giving this off, and therefore losing mass, black holes will eventually evaporate altogether if they don’t have another source of mass to sustain them; for example interstellar gas or light. (Source)

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 Holes Are 'Portals To Other Universes,' According To New Quantum Results

According to Albert Einstein’s theory of general relativity, black holes are uninhabitable chasms of space-time that end in a “singularity,” or a mass of infinite density. It’s a place so bleak that even the laws of physics break down there. But what if black holes aren’t so forbidding? What if they are instead some kind of intergalactic stargate, or maybe even a passageway into a whole other universe?

It may sound like the premise for a clever science-fiction movie, but new calculations by quantum physicists now suggest that the stargate idea might actually be the better theory. According to the startling new results, black holes do not culminate in a singularity. Rather, they represent “portals to other universes,” reports New Scientist.

This new theory is based on a concept known as ‘loop quantum gravity’ (or LQG). It was first formulated as a way of merging standard quantum mechanics and standard general relativity, in order to remedy incompatibilities between the two fields. Basically, LQG proposes that spacetime is granular, or atomic, in nature; It is made up of miniscule, indivisible chunks about the same size as the Planck length — which roughly amounts to 10-35 meters in size.

Researchers Jorge Pullin from Lousiana State University, and Rodolfo Gambini from the University of the Republic in Montevideo, Uruguay, crunched the numbers to see what would happen inside a black hole under the parameters of LQG. What they found was far different from what happens according to general relativity alone: there was no singularity. Instead, just as the black hole began to squeeze tight, it suddenly loosened its grip again, as if a door was being opened.

It might help to conceptualize exactly what this means if you imagine yourself traveling into a black hole. Under general relativity, falling into a black hole is, in some ways, much like falling into a very deep pit that has a bottom, only instead of hitting the bottom, you get pressed into a single point — a singularity — of infinite density. With both the deep pit and the black hole, there is no “other side.” The bottom stops your fall through the pit, and the singularity “stops” your fall through the black hole (or at least, at the singularity it no longer makes sense to say you’re “falling”).

Your experience would be much different traveling into a black hole according to LQG, however. At first you might not notice the difference: gravity would increase rapidly. But just as you were nearing what ought to be the black hole’s core — just as you’re expecting to be squashed into the singularity — gravity would instead begin to decrease. It would be as if you were swallowed, only to be spit out on the other side.

In other words, LQG black holes are less like holes and more like tunnels, or passageways. But passageways to where? According to the researchers, they could be shortcuts to other parts of our universe. Or they could be portals to other universes entirely.

Interestingly, this same principle can be applied to the Big Bang. According to conventional theory, the Big Bang started with a singularity. But if time is rewound according to LQG instead, the universe does not begin with a singularity. Rather, it collapses into a sort of tunnel, which leads into another, older universe. This has been used as evidence for one of the Big Bang’s competing theories: the Big Bounce.

Scientists don’t have enough evidence to decide whether this new theory is actually true, but LQG does have one thing going for it: it’s more beautiful. Or rather, it avoids certain paradoxes that conventional theories do not. For instance, it avoids the black hole information paradox. According to relativity, the singularity inside a black hole operates as a sort of firewall, which means that information that gets swallowed by the black hole gets lost forever. Information loss, however, is not possible according to quantum physics.

Since LQG black holes have no singularity, that information need not be lost.

“Information doesn’t disappear, it leaks out,” said Jorge Pullin.


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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. 

Researcher shows that black holes do not exist

Black holes have long captured the public imagination and been the subject of popular culture, from Star Trek to Hollywood. They are the ultimate unknown – the blackest and most dense objects in the universe that do not even let light escape. And as if they weren’t bizarre enough to begin with, now add this to the mix: they don’t exist.

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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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Stephen Hawking: ‘There are no black holes’

Most physicists foolhardy enough to write a paper claiming that “there are no black holes” — at least not in the sense we usually imagine — would probably be dismissed as cranks. But when the call to redefine these cosmic crunchers comes from Stephen Hawking, it’s worth taking notice. In a paper posted online, the physicist, based at the University of Cambridge, UK, and one of the creators of modern black-hole theory, does away with the notion of an event horizon, the invisible boundary thought to shroud every black hole, beyond which nothing, not even light, can escape.

In its stead, Hawking’s radical proposal is a much more benign “apparent horizon”, which only temporarily holds matter and energy prisoner before eventually releasing them, albeit in a more garbled form.

“There is no escape from a black hole in classical theory,” Hawking told Nature. Quantum theory, however, “enables energy and information to escape from a black hole”. A full explanation of the process, the physicist admits, would require a theory that successfully merges gravity with the other fundamental forces of nature. But that is a goal that has eluded physicists for nearly a century. “The correct treatment,” Hawking says, “remains a mystery.”

Hawking posted his paper on the arXiv preprint server on 22 January. He titled it, whimsically, ‘Information preservation and weather forecasting for black holes’, and it has yet to pass peer review. The paper was based on a talk he gave via Skype at a meeting at the Kavli Institute for Theoretical Physics in Santa Barbara, California, in August 2013 (watch video of the talk).

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Black holes are the seductive dragons of the universe, outwardly quiescent yet violent at the heart, uncanny, hostile, primeval, emitting a negative radiance that draws all toward them, gobbling up all who come too close. Once having entered the tumultuous orbit of a black hole, nothing can break away from its passionate but fatal embrace. Though cons of teasing play may be granted the doomed, ultimately play turns to prey and all are sucked haplessly―brilliantly aglow, true, but oh so briefly so―into the fire-breathing maw of oblivion. Black holes, which have no memory, are said to contain the earliest memories of the universe, and the most recent, too, while at the same time obliterating all memory by obliterating all its embodiments. Such paradoxes characterize these strange galactic monsters, for whom creation is destruction, death life, chaos order. And darkness illumination: for, as dragons are also called worms, so black hole are known as wormholes, offering a mystical and intimate pathway to the farthest reaches of the cosmos, thus bring light as they consume it.
—  Robert Coover