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Stephen Hawking: “The Absence of Event Horizons Means There are No Black Holes"

 

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Stephen Hawking has set the world of physics back on its heels by reversing his lifetime’s work and a pillar of modern physics claiming that black holes do not exist – saying that the idea of an event horizon, the invisible boundary thought to shroud every black hole --the awesome gravitational pull created by the collapse of a star will be so strong that nothing can break free including light-- is flawed. Hawking proposes that instead of an inescapable event horizon, we should think of an “apparent horizon”.

“The absence of event horizons means that there are no black holes — in the sense of regimes from which light can't escape to infinity.” “There is no escape from a black hole in classical theory. [But quantum theory] enables energy and information to escape from a black hole," Hawking told Nature. His revised theory allows matter and energy to be held for a period of time before being released back into space.

Hawking says that his revsion requires a new theory that merges gravity with the other fundamental forces of nature. “The correct treatment remains a mystery,” he observed.

Hawking posted his paper, 'Information preservation and weather forecasting for black holes', on the arXiv preprint server. 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. leading theoretical physicist Joseph Polchinski of the Kavli Institute to comment that “In Einstein’s gravity, the black-hole horizon is not so different from any other part of space. We never see space-time fluctuate in our own neighbourhood: it is just too rare on large scales.”

Raphael Bousso, a theoretical physicist at the University of California, Berkeley, and former student of Hawking's, observes via nature.com, that “The idea that there are no points from which you cannot escape a black hole is in some ways an even more radical and problematic suggestion than the existence of firewalls. But the fact that we’re still discussing such questions 40 years after Hawking’s first papers on black holes and information is testament to their enormous significance."

Hawking's revised theory is an attempt to solve what is known as the black-hole firewall paradox, which has been vexing physicists for almost two years, after it In a thought experiment discovered by theoretical physicist Joseph Polchinski of the Kavli Institute and his colleagues, who asked what would happen to an astronaut unlucky enough to fall into a black hole.

The notion of a firewall obeyed quantum rules, but flouts Einstein’s general theory of relativity. According to that theory, observes Nature.com, "someone in free fall should perceive the laws of physics as being identical everywhere in the Universe — whether they are falling into a black hole or floating in empty intergalactic space. As far as Einstein is concerned, the event horizon should be an unremarkable place."

Hawking proposes a third option in which quantum mechanics and general relativity remain intact, but quantum effects around the black hole cause space-time to fluctuate too wildly for a sharp boundary surface to exist.

The image at the top of the page of NGC 6240 contains new X-ray data from Chandra (shown in red, orange, and yellow) that has been combined with an optical image from the Hubble Space Telescope. In 2002, the discovery of two merging black holes was announced based on Chandra data in this galaxy. The two black holes are a mere 3,000 light years apart and are seen as the bright point-like sources in the middle of the image.

Scientists think these black holes are in such close proximity because they are in the midst of spiraling toward each other -- a process that began about 30 million years ago. It is estimated that the two black holes will eventually drift together and merge into a larger black hole some tens or hundreds of millions of years from now.

The formation of multiple systems of supermassive black holes should be common in the Universe, since many galaxies undergo collisions and mergers with other galaxies, most of which contain supermassive black holes. It is thought that pairs of massive black holes can explain some of the unusual behavior seen by rapidly growing supermassive black holes, such as the distortion and bending seen in the powerful jets they produce. Also, pairs of massive black holes in the process of merging are expected to be the most powerful sources of gravitational waves in the Universe.

Sources: Nature doi:10.1038/nature.2014.14583 and Hawking, S. W. Preprint at http://arxiv.org/abs/1401.5761 (2014)http://arxiv.org/abs/1401.5761 (2014)

The Daily Galaxy via  Express  and Nature

          

 

          

Comments

Now let us hope Hawking discounts Einstein's other misnomers. General Relativity theory of orbital decay, curved space and those mysterious gravity waves, all of which do NOT exist, which has set physics back nearly 100 yrs.
Can we please get back to scientifically backed observed science.

I have seen several postings that claim that if black holes do exist then galaxies would have to be spherical not disk shaped.

To those I would refer you to GALACTIC Law of Rotation by L Mestel, 1963 Royal Astronomical Society, August 1963 p 553.

A spherical gas distribution only needs a perturbation in the thermal motion to cause a transformation to a disk like shape.

Makes me wonder if a black hole is a disk with infinite thinness or a sphere. On Hawking I guess even the elites make mistakes. Of course it appears that Dr. Hawking is also his own arbitrator.

Journalistic hacks are a pain. Please have the courtesy and intellectual integrity to quote the great man accurately and not out of context. What he wrote was, “The absence of event horizons means that there are no black holes — IN THE SENSE OF regimes from which light can't escape to infinity.” He never said or meant to imply black holes do not exist.

Well, I'm thinking Bell was more referring to the concept that the surface area grows with the mass, not the volume growing with the mass. In other words if I quadruple the mass, I double the radius. In theory, the volume of space displaced (as measured by apparent radius of the 'lensing' effect) could grow faster and faster even if mass absorbed is at a flat rate. Thing is, space seems to be growing faster than that. ;)

Well, for my own 2-cents... We could think of anti-event-horizons as working like this. You have a maximum amount of distance that structures can occupy before the light emitted in one part can't possibly reach some specific other part. This is also known as the maximum computing problem (size of the most powerful theoretical computer that can view any specific location in it's own memory in a finite amount of time). You effectively not only have a horizon going inwards towards a black hole, but you also have a maximum distance outwards away from it, for any given moment. You may only view photons emitted between those points. In the big rip(see also big crunch) theory, effectively these two radii meet. The traditional laymen's description is that even a hydrogen atom rips itself apart since the electron can no longer be aware that there is a proton over it's light cone. TL;DR version is that the universe becomes separated into spaces smaller than an atom's nucleus and all matter goes to Hades. :P

Note, assuming no uncertainty principle ahead. Yes, I know there is but it's still an interesting idea as even though we know that QM is needed for magnetism, there is a classical theory that somehow still works reliably. An interesting concept is that if there are anti-gravitons and gravitons have negative mass-energy, and can ONLY interact at the surface of particle's singularities, then it explains gravity in terms of graviton absorption/emission. When a graviton is absorbed much like a photon, the antigraviton combines to produce negative mass-energy much like how two photons can make mass (matter-antimatter pairs). Bah forget this paragraph, I was just tired and thought of it... Nothing serious. The math seems horribly wrong on rereading but maybe someone can work it out as a useful concept.

Actually, my calculus lessons seem to be coming back to me, and the radius of a black hole growing mass spread over a surface area would have a trivial-to-determine velocity(rate) derivative. But it's not even required to use calculus. The mass in a volume of space is definitely more compact overall than that same mass spread over a (thinner) surface, _if the components are the same average distance from their nearest neighbor_. Thing is, it's kind of like saying a lattice form of carbon (like say, graphite) is stronger than a diamond just because the bonds are stronger between atoms in a layer. The average distance between any 2 particles (or even simpler, the nearest neighbor) is much higher for the cubic solution of volume of space than for the surface of an (apparent) event horizon.

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