Hawking Radiation

unstablestar  asked:

Can black holes die? if not, then is it possible for black holes to continue merging and expanding until all matter in the universe is pulled into one big massive black hole? if black holes can die then what happens with the matter that has been pulled in by the gravitational force? would a white hole then be produced after the black hole dies?

Black holes can, in fact, die! The way they die, however, is theoretical and not proven, but it’s possible and it’s called Hawking radiation. To summarize // oversimplify (because it’s really complicated), according to quantum physics we know that particle-antiparticle pairs pop in and out of existence all the time, and usually annihilate each other almost immediately. They are able to come into existence by “borrowing” energy from the universe, and when they annihilate they “return” that energy back.

Now, what if a particle-antiparticle pair comes into being right at the edge of a black hole’s event horizon, and one particle falls in and the other escapes? Well, now you’ve just “created” one particle that’s entered the universe, and one particle that’s entered the black hole (and can’t escape). Since these two particles can’t annihilate, they can’t “return” their borrowed energy to the universe. However, you can’t just spontaneously create energy; it has to come from somewhere. That somewhere is, you guessed it, the black hole. So, the amount of energy in the black hole decreases by the amount of energy required to create the particle-antiparticle pair. Since mass and energy are equivalent (e=mc2), the mass of the black hole decreases ever so slightly - the mass of an electron, positron, or other subatomic particle. 

This process takes billions of years, and it will be another several billion years before we’re able to see black holes finish evaporating. This process is expected to be faster the smaller the black hole is - once a black hole is small enough, this process happens faster and faster, until the black hole gives off lots and lots of radiation and “explodes” (think: gamma rays, really bright, as bright or brighter than a supernova), and no longer exists. While this isn’t proven and is entirely theoretical, it’s pretty cool that black holes, the killers of the universe from which nothing should be able to escape, are slowly losing mass over billions and trillions of years, one subatomic mass at a time.


Ask Ethan: What Happens When A Black Hole’s Singularity Evaporates?

“What happens when a black hole has lost enough energy due to hawking radiation that its energy density no longer supports a singularity with an event horizon? Put another way, what happens when a black hole ceases to be a black hole due to hawking radiation?”

One of the most puzzling things about Black Holes is that if you wait around long enough, they’ll evaporate completely. The curved spacetime outside of the event horizon still undergoes quantum effects, and when you combine General Relativity and quantum field theory in exactly that fashion, you get a blackbody spectrum of thermal radiation out. Given enough time, a black hole will decay away completely. But what will that entail? Will an event horizon cease to exist, exposing a former black hole’s core? Will it persist right until the final moment, indicative of a true singularity? And how hot and energetic will that final evaporative state be?

Incredibly, even without a quantum theory of gravity, we can predict the answers! Find out on this week’s Ask Ethan.

Simulating a black hole

40 years ago Stephen Hawking predicted that black holes emit a special kind of radiation. Consequently black holes are theoratically able to shrink and even vanish. This radiation arises when virtual particles (pairs of particles developing because of quantum fluctuations inside the vacuum; usually they nearly instantly destroy each other) are near the event horizon. Then the virtual particle pair gets divided: one disappears in the black hole (and its quantum mechanical information) and the other one becomes real. Thus the black hole radiates but unfortunately this radiation is so low that astronomical observations are nearly impossible.
Therefore scientists have to simulate black holes to get empirical evidence. The physicist Jeff Steinhauer of the Technion, the University of Technology of Haifa in Israel exactly did this. He realized an idea of physicist Bill Unruh with an acoustical event horizon. He uses a fog made of rubidium atoms which is only slightly above the absolute zero. Because they are trapped inside an electromagnetic field these atoms become a Bose-Einstein Condensate. Inside of this condensate the acoustic velocity is only a half millimeter per second. With the help of accelerating some above this speed an artificial event horizon is created. The low temperatures lead to quantum fluctuations: pairs of phonons develop. In the simulation these pairs also get divided: one gets caught by the supersonic event horizon; the other one becomes some kind of Hawking radiation.
It is still not sure if this experiment really simulates black holes. According to Ulf Leonhardt it does not proof for sure that the two phonons are entangled. Thus it is not sure if the pairs arised out of one fluctuation. Leonhardt even doubts that the fog of atoms is a real Bose-Einstein Condensate. Leonard Susskind thinks this experiment does not reveal the mysteries of black holes: for instance it does not explain the information paradox, because acoustic black holes do not destroy information.

In this dream, I was reading about a discovery that in significantly large systems of language (long sentences, long books, printings, the internet), there was a mathematically describable probability that adverbs would be randomly switched as an apparent “accident”.

I loved this, and was explaining it to someone else, along with the idea that has been discussed in real life that populations are surveyed and studied, as systems of knowledge become more certain, that the old formulas cease to apply and behavior in those systems becomes random. A kind of Heisenberg Uncertainty of Everything. This was similar, but in my mind I think I was comparing it to Hawking radiation? AH! NO! This is what that was.

I was discussing this article over coffee with Z, and explaining why I believed this strange equation was true, not because I liked it but because it seems to be how the world works. Then I started talking about how the duality between reason and dialectical thought was rooted in the same paradoxical dualism that makes the universe indescribable by a Unified Field Theory (screw you Higgs Boson).

What we call negation is what is described by probabilities in the sciences. The concept of time is nullified by the constant presence of the totality, and the dialectic follows from the structure hidden below in the mathematics. And the absolute negative acts as a kind of Hawking radiation from the void of thought. A mysterious energy that allows us to sense singularities-in-thought.

Earlier in the dream, someone from The Music Box asked me to evaluate some scripts. 

for @antcommander

Hawke’s hands are so much larger than his own. He presses fingertip against fingertip, softly moving to his palm. Tracing the lines which web, all the little cracks in skin, circling every bump and bone. A smile quirks on his lips when he sees Hawke’s fingers twitch with the feeling, even as he sleeps. His breathing even and calm, eyes closed and peaceful in dreaming. Fenris lies beside him, hand drifting over hand, as the fire begins to ebb down low.

Soft warm light, flickering over the both of them. Fenris traces the line of Hawke’s nose, the worrisome line of his mouth. A thumb drifting over lips, a feel he knows too well and not well enough. He moves through his beard, follows his jaw to the shell of his ears. Through coal colored hair, and back down again. Over shoulder to collarbone, to the well in the middle, broad chest and sturdy ribs, the heart that beats underneath.

He feels it underneath his palm, that steady rhythm, a peaceful song. He closes his eyes, feels the heat that radiates from Hawke. His eyes open again when a hand slips over his own. “What are you doing?” He asks, voice hoarse from sleep, his eyes barely able to remain open. Fenris shakes his head, pulls at the hair on Hawke’s chest. Hawke swats his hand away with a yelp. Fenris falls back into the bed, long white hair splaying out over the pillow.

“You are like a big, hairy bear,” Fenris says.

“And you are a small, handsome elf,” Hawke tells him with a smile. Fenris lets out a huff, crossing his arms, turning his face away from Hawke. It hides the slight shade of red that blossoms on his cheeks. Hawke tells him often - how handsome, how kind, how sweet… He never knows how to respond.

“I am of average size for an elf.” Hawke laughs, rolling over to drape an arm over Fenris’s chest, burying his head into the crook of his neck.

“Tell what you were doing,” Hawke murmurs, pressing a kiss to his neck.

“I was,” Fenris pauses, mulling it over, “memorizing.” Hawke shifts, raising himself up, hands pressing into the mattress. He leans over Fenris, until he finds the eyes that will not meet his own. Even without seeing it properly in the low light, he knows the blush that troubles Fenris’s cheeks.

“Does that mean I get to do the same?” Hawke leans back, moving to kneel at the end of the bed. Fenris doesn’t protest as Hawke pulls down the blanket, simply moving to lean against the headboard, watching as Hawke moves. The first touch is light against his ankle. Fingertips that come to rest against skin, feeling the heat of Hawke’s palm. His thumb moves in slow, affectionate, circles. Hawke smiles up at Fenris as he begins to move.

He keeps his thumb on the line of bone, drifting upwards. He takes care not to trace markings, lyrium chains, and shows his appreciation for all that Fenris is. Hawke glances up from his work often, to see the yes in Fenris’s expression, the way he bites at his bottom lip. He circles around Fenris’s knee, and ever upwards. A hand kneads against his thigh, teasing touches that never quite go where Fenris wants him to. Hawke smiles at Fenris’s intake of breath when his touch get near, then shifts to his hips.

He trails a finger over hipbones, and splays a hand over Fenris’s belly. He appreciates the hard muscle he feels, satisfaction in knowing that it’s not just muscle now – Hawke’s cooking has seen to that. Strong hands over ribs, a squeezing that isn’t tight, until Hawke cups his face in his hands.

Hawke leans forward, brushes lips over Fenris’s. A light kiss but deepening still, Fenris is lost when Hawke pulls away. Eyes half-lidded, a hand on Hawke’s arm. More than his human heat, more than the fire, there’s a burning of warmth in Hawke’s eyes - a fondness that Fenris melts underneath. “I know all of you,” Hawke says as he tucks a lock of hair behind pointed ears, “I love every inch.”

I’ve posted about it before, my brain being a goddamn nightmare, and it’s gotten to the point where I can’t even sleep at night because my brain is just “What about this? Would this make an experiment? Let’s think about the physics of black holes!! Let’s find a way to test string theory!! If you add these 18 equations together you can figure out this problem!! The data from lab today! Let’s think about the best way to analyze it to visualize the results!! Let’s learn about tachyons!!! Let’s read every scientific mumbling about Hawking radiation!!” And oh my god I can’t sleep. The only way I can sleep is to somehow inebriate myself with alcohol or nicotine or pot to get my brain to SHUT UP. I’m missing classes because my brain won’t let me go to fucking sleep. I’m up at 4am with my big ass whiteboard deriving black hole physics. I’m sitting on my floor smoking a cigarette with 13 academic papers sprawled out around me trying to connect the dots like a lunatic. I WANT TO SLEEP

Quantum bounce could make black holes explode

If space-time is granular, it could reverse gravitational collapse and turn it into expansion.

Black holes might end their lives by transforming into their exact opposite — ‘white holes’ that explosively pour all the material they ever swallowed into space, say two physicists. The suggestion, based on a speculative quantum theory of gravity, could solve a long-standing conundrum about whether black holes destroy information.

Continue Reading

willygowild  asked:

Is it possible, or even merely,..Plausible, that black holes, "theoretically", might perhaps be more akin to, say, a super-massive quantum? They DO have a "life cycle" so to speak. If Occam's razor is more or less, universally given to prove factual,..When a caterpillar transform into moth/butterfly,..The caterpillar, did NOT die,..It simply moved to another state of being,. And merely, became, something else. Far grander than its lowly crawling beginnings.So, what do you think?

I’m not sure what you mean by ‘super-massive quantum’ BHs. So, forgive me if I misinterpreted your question. Here’s what I know:

Quantum mechanical black holes may have formed in the early stages of the universe. We call these primordial black holes (PBHs). What’s really interesting about primordial black holes is that they are not the result of collapsing stars. According to general relativity, the key ingredient is basically a region of high density matter – like the quark soup, add some intense energy density fluctuation to that region of space (inflation) and you get an increased amount of matter within a Schwarzschild radius, and voilà, a miniature event horizon is born. Of course, PBHs could span an enormous mass range; those formed in the Planck epoch would have the tiny Planck mass (10^−5g),  and those formed 1 second after the Big Bang would be as large as 10^5 solar masses - like the ones thought to reside in the center of galaxies. These PBHs may still be with us today because the rate at which a black hole evaporates (Hawking radiation) is inversely proportional to its mass; a small black hole evaporates rapidly, and a massive black hole, therefore, evaporates slowly.  The smaller ones that have evaporated left some clues behind; they produced a huge amount of radiation which affected and delayed the onset of nuclei formation (nucleosynthesis), we know this because we measured the abundance of those nuclei. There is a possibility that the observed baryon asymmetry was generated by the evaporation of PBHs. The ones that are still evaporating are actually plausible dark matter candidates, they are a bit different from the typical dark matter candidates, of course, because they are not elementary particles like the weakly interacting massive particles (WIMPs), rather massive astrophysical compact halo objects (MACHOs). The other interesting thing is that we don’t really know the end result of evaporating black holes, maybe they shrink to the Planck scale and circle around the universe as Planck-mass relics.

Black Hole

Black holes, the weirdest thing in the space.  When you look at the black hole you are looking at event horizon {as the event horizon is the black part of black hole}, it is impossible to cross event horizon even light can not escape the event horizon, so anything which tries to crosses the event horizon needs to be travel faster than the speed of light which is impossible as light also can’t escape the event horizon. As the event horizon is the black part of a black hole. So what is the center of the black hole? Singularity a singularity is infinitely dense it means all its mass is contrasted to the single point where there is no surface or no volume. If an object is size of black hole and if the black hole will suck that object so there will be no black hole remaining. So what will happen if you able to get in the black hole? For you time will get slower {as you will travel too fast} so you can see the future of the universe, but we are not quite sure what will happen. It could be possible that you could die but we don’t know, but what do we know is about hawking radiation, as all the black hole in the universe will die one day or another because of empty space, as in empty space virtual practicals came into existence and annihilate each other. When this process happens at the edge of a black hole then practical which is inside of the black hole will get inside the black hole and the outside particle will be deflected to the outside, so the black hole is losing the energy but this process is very slow. So we can say that black hole will die someday.

Scientists make waves with black hole research: Water bath simulation

Scientists at the University of Nottingham have made a significant leap forward in understanding the workings of one of the mysteries of the universe. They have successfully simulated the conditions around black holes using a specially designed water bath.

Their findings shed new light on the physics of black holes with the first laboratory evidence of the phenomenon known as the superradiance, achieved using water and a generator to create waves.

Keep reading


Ask Ethan #103: Have We Solved The Black Hole Information Paradox?

“How is Hawking’s theory of black holes storing information on the shell of an event horizon different than what Susskind said decades ago about black holes storing information on the shell of an event horizon? Did Hawking just pull a Steve Jobs and proclaim something new that Android figured out years before? Or is this actually new stuff?”

Stephen Hawking is claiming that the black hole information paradox has now been resolved, with the information encoded on the event horizon and then onto the outgoing radiation via a new mechanism that he’ll detail in a paper due out next month, along with collaborators Malcom Perry and Andrew Strominger. Only, that’s not really what’s happening here. While he does have a new idea and there is a paper coming out, its contents do not solve the information paradox, but merely provide a hypothesis as to how it may be solved in the future.


Best of 2014!













Still not satisfied? Relive the previous year in science!

A black hole is a mathematically defined region of spacetime exhibiting such a strong gravitational pull that no particle or electromagnetic radiation can escape from it. The theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of the region from which no escape is possible is called the event horizon. Although crossing the event horizon has enormous effect on the fate of the object crossing it, it appears to have no locally detectable features. In many ways a black hole acts like an ideal black body, as it reflects no light. Quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is on the order of billionths of a Kelvin for black holes of stellar mass, making it essentially impossible to observe. Objects whose gravitational fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace. The first modern solution of general relativity that would characterize a black hole was found by German physicist and astronomer Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958. Long considered a mathematical curiosity, it was during the 1960s that theoretical work showed black holes were a generic prediction of general relativity. The discovery of neutron stars sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality. 

Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed, it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses (M☉) may form. There is general consensus that supermassive black holes exist in the centers of most galaxies. Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light. Matter falling onto a black hole can form an accretion disk heated by friction, forming some of the brightest objects in the universe. If there are other stars orbiting a black hole, their orbit can be used to determine its mass and location. Such observations can be used to exclude possible alternatives (such as neutron stars). In this way, astronomers have identified numerous stellar black hole candidates in binary systems, and established that the core of the Milky Way contains a supermassive black hole of about 4.3 million M☉.

Bad Luck: Part Four

BOOM!! This is a really long chapter and I hope you like it :)

Part One   Part Two   Part Three

Adrien had barely slept, he only got about two hours of sleep and he was exhausted. There was also the fact the he had a photo shoot today… Right after school, then another tomorrow and after tomorrow? It was the ball. So it had to be today that Adrien told Marinette and he wasn’t looking forward to it at all.

Sighing, the model got dressed and was on his way to school… He got there a little early so that he could wait for Marinette; something he had been doing ever since their accidental kiss. He used to love them, but today he dreaded it.

Keep reading

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)

Energy Teleport Study Could Unlock Quantum Computer, Black Hole Secrets

by Charles Q. Choi

Energy could in theory be teleported over any distance, researchers in Japan say. The science team behind the discovery said such quantum energy transfer could help advance quantum computers and shed light on the mysteries of black holes.

Teleporting an object from one point in the universe to another without it traveling through the space in between might sound like part of a Star Trek episode, but scientists have actually been doing it since the 1990s. The current long-distance record for teleportation is roughly 89 miles, a feat that was announced in 2012 between the two Canary Islands of La Palma and Tenerife off the northwest coast of Africa.

Keep reading


Black holes and academic walls

“This “Hawking radiation” is composed of particles that besides their temperature do not contain any information. And so, when a black hole entirely evaporates all the information about what fell inside must ultimately be destroyed. But such destruction of information is incompatible with the very quantum theory one used to arrive at this conclusion. In quantum theory all processes can happen both forward and backward in time, but black hole evaporation, it seems, cannot be reversed.”

100 years ago, Einstein put forth his General Theory of Relativity, and 99 years ago, Karl Schwarzschild came up with the mathematical solution describing a black hole, a solution we now know is not only physically valid, but one that has many examples all across the Universe. Yet when you consider quantum physics, the matter gets complicated: while you ought to be able to run the laws of physics the same forwards and backwards, a black hole seems to wind up in an irreversibly different state, in the end, from what you started with. That’s the root of the black hole information paradox. Sabine Hossenfelder has all the latest on the topic.

Yes, they do—Stephen Hawking discovered that according to quantum mechanics, black holes should radiate energy. In the quantum world, space is filled with tiny particles that flash in and out of existence, and Hawking predicted that energy fluctuations would generate particle-antiparticles near a black hole’s event horizon. Before they can annihilate each other as would normally happen, the black hole pulls in the particle with negative energy and “emits” the particle with positive energy. For this reason, black holes aren’t completely black—they glow faintly.

This is called Hawking Radiation, and it results in the black hole losing energy and therefore mass according to E=mc^2. As a black hole radiates, it shrinks. The nature of the radiative process means that the more a black hole shrinks, the more it radiates—so eventually the black hole will disappear. This will take an incredibly long time, though. A black hole of the mass of the Sun will take a billion times a billion times a billion times a billion times a billion times a billion times the age of the universe to evaporate completely.