Space.com clara Moskowitz, Space.com Senior Writer
space.com – Thu Jan 27, 3:30 pm ET

The end of a black hole’s evolution may be a mind-bending kind of space-time independent of time. A new study proposes a method to tell how far any black hole is from reaching this end state.

Black holes are some of the weirdest things in the universe. They occur when mass is packed into a tiny volume, squished to its ultimate density.

Though observations suggest black holes are prevalent in the universe, scientists still don't really understand what goes on inside them. The equations of general relativity usually used to understand the physics of the universe break down in these cases.

"It is really beyond the physics we know," said Juan Antonio Valiente Kroon, a mathematician at Queen Mary, University of London. "To understand what happens inside a black hole, we need to invent new physics."

Mercifully, the physics for the end state of a black hole is somewhat simpler. A solution to the equations of general relativity was found that produced a situation called "Kerr spacetime." Scientists now think Kerr spacetime is what happens when a black hole has reached its final evolutionary state.

"Mainly the equations of relativity are so complex that for relativistic systems, the only way you can probe these equations is by means of computer," Valiente Kroon told SPACE.com. "Solutions like this Kerr solution are really exceptional. The Kerr solution is one of the few explicitly known solutions to general relativity that have a direct physical meaning."

Kerr spacetime is time-independent, meaning that nothing in Kerr spacetime changes over time. In effect, time stands still. A black hole in such a state is essentially stationary.

"One could say once it has reached this stage, there are no further processes taking place," Valiente Kroon said.

In their new study, Valiente Kroon and Thomas Backdahl, his colleague at Queen Mary, have calculated a formula to determine how close a black hole is to reaching the Kerr state.

This can happen very quickly – even in seconds – depending on the object's mass.

To apply the formula, scientists would examine the region around a black hole called its event horizon. Once mass, or even light, passes within the event horizon of a black hole, it cannot escape the black hole's gravitational clutches.

The researchers think their development could aid scientists who are building computer simulations of black holes and aiming to align them with observations of actual black holes.

Astronomers think most galaxies, including our own Milky Way, host supermassive black holes in their centers. Some researchers suspect that these are actually Kerr black holes.

Valiente Kroon and Backdahl detail their work in the Jan. 19 issue of the journal Proceedings of the Royal Society A.

You can follow SPACE.com senior writer Clara Moskowitz on Twitter @ClaraMoskowitz.

are they just guessing now? this just seems stupid... but they are scientists...

In general relativity, the Kerr metric (or Kerr vacuum) describes the geometry of spacetime around a rotating massive body. According to this metric, such rotating bodies should exhibit frame dragging, an unusual prediction of general relativity. Measurement of this frame dragging effect was a major goal of the Gravity Probe B experiment. Roughly speaking, this effect predicts that objects coming close to a rotating mass will be entrained to participate in its rotation, not because of any applied force or torque that can be felt, but rather because of the curvature of spacetime associated with rotating bodies. At close enough distances, all objects — even light itself — must rotate with the body; the region where this holds is called the ergosphere.

The Kerr metric is often used to describe rotating black holes, which exhibit even more exotic phenomena. Such black holes have different surfaces where the metric appears to have a singularity; the size and shape of these surfaces depends on the black hole's mass and angular momentum. The outer surface encloses the ergosphere and has a shape similar to a flattened sphere. The inner surface marks the "radius of no return" also called the "event horizon"; objects passing through this radius can never again communicate with the world outside that radius. However, neither surface is a true singularity, since their apparent singularity can be eliminated in a different coordinate system. Objects between these two horizons must co-rotate with the rotating body, as noted above; this feature can be used to extract energy from a rotating black hole, up to its invariant mass energy, Mc2. Even stranger phenomena can be observed within the innermost region of this spacetime, such as some forms of time travel. For example, the Kerr metric permits closed, time-like loops in which a band of travellers returns to the same place after moving for a finite time by their own clock; however, they return to the same place and time, as seen by an outside observer.

The Kerr metric is an exact solution of the Einstein field equations of general relativity; these equations are highly non-linear, which makes exact solutions very difficult to find. The Kerr metric is a generalization of the Schwarzschild metric, which was discovered by Karl Schwarzschild in 1916 and which describes the geometry of spacetime around an uncharged, perfectly spherical, and non-rotating body. The corresponding solution for a charged, spherical, non-rotating body, the Reissner–Nordström metric, was discovered soon afterwards (1916–1918). However, the exact solution for an uncharged, rotating body, the Kerr metric, remained unsolved until 1963, when it was discovered by Roy Kerr. The natural extension to a charged, rotating body, the Kerr–Newman metric, was discovered shortly thereafter in 1965. These four related solutions may be summarized by the following table:
Non-rotating (J = 0) Rotating (J ≠ 0)
Uncharged (Q = 0) Schwarzschild Kerr
Charged (Q ≠ 0) Reissner–Nordström Kerr–Newman

where Q represents the body's electric charge and J represents its spin angular momentum.

I was feeling pretty good about myself for managing to figure out and program my new DVR this morning...


Until I tried to read and digest all this, that is...

i think it all means that either they are smarter than me, or have a bigger imagination... i'm guessing the latter

At one point in time (about 23 years ago), I knew quite a bit about black holes, how they were formed, the mathematics behinds them, the theories, etc. Being a math and science geek in high school, I had a fascination with them. But now I have forgotten most of that information as I began focusing on other issues in my life.

Over the years I have read a bit here and there about new discoveries and theories concerning black holes. My general opinion has been that these scientists are beginning to overthink, or maybe even pushing to hard to discover or prove new theories. It is as if they lose sight of the big picture.

It is my belief (and I am no scientist) that black holes are how dead stars are reborn....a cycle of expansion and contraction of death and creation. A black hole simply absorbs mass, but as it does so, it's overall density decreases. Since gravity is linked to both mass and density, eventually it diminishes too, but not before igniting the material absorbed by the black hole's core. Once the gravity diminishes sufficiently, light can then escape revealing a new star in place of the black hole. This process likely takes millions or billions of years which means no living person has ever witnessed such an event.

Eventually this star will likely go supernova, become a black hole, and begin the cycle again. Sort of like a cosmic recycling plant. It helps to explain how galaxies are created and why they expand and contract. It also means that there may not have been one Big Bang, but perhaps several.

I once mentioned this to a coworker about 3 years ago, and then last year I saw an issue of Discover magazine whose cover article dealt with evidence possibly pointing to this theory. Of course, I had to buy the magazine to read the article. (Discover, Dec. 2009,
"Dawn of the Black Holes", p. 52) For once, it looked as if someone with the scientific community might share my belief.

The problem with the Big Bang theory is that it was meant to explain Creation but does not explain how the matter came into being previous to the Big Bang. Hence Sci-Fi's fascination with resolving Science and Religion. Therefore, scientists often do tend to grasp at straws, and it is the rare few that actually stumble upon something important and valid. After all, look at how long it took Milankovitch's theory to be accepted regarding the Ice Ages. Einstein's theories are much of the basis of modern research regarding black holes. The Theory of Relativity has never been proven, and yet every attempt to DISPROVE it has failed. Eventually, one or the other will happen, and it will have a dramatic impact on cosmic research. Before that happens, it will take one of those rare scientists to come forward with something new. Even then, it will be decades before his research is accepted.

good post, i agree with it 100%. I also feel, since we are secluded in our own little part of the universe, that there are some things that cannot be proven until we get to other parts of the universe. I have always thought that about the big bang theory, that one explosion created everything in the universe is a bit much. Black Holes have to have a breaking point, when one gets full, what happens then?

Time stops at the speed of light (from the perspective of a ray of light there is no movement through time). Light slows down in a gravity field. At the center of a black hole light stops moving. That means that for matter in the center of a black hole time may not have meaning.

Yes, mind boggling.

not sure about the over thinking part but ... if we take string theory into the picture then lots of things change... the big bang is losing its appeal.

a multiverse is taking form and black holes may be the portals between universes. ... my thought.

its all done with math ... and math now says there are many many universes.

just think fractels and add universes.

time is a perception, there is no substance to it, no matter involved with it, and no light rays. How can gravity effect something that is not there?

"The most massive known black hole in the universe has been discovered, weighing in with the mass of 18 billion Suns. Observing the orbit of a smaller black hole around this monster has allowed astronomers to test Einstein's theory of general relativity with stronger gravitational fields than ever before.

The black hole is about six times as massive as the previous record holder and in fact weighs as much as a small galaxy. It lurks 3.5 billion light years away, and forms the heart of a quasar called OJ287. A quasar is an extremely bright object in which matter spiralling into a giant black hole emits copious amounts of radiation.

But rather than hosting just a single colossal black hole, the quasar appears to harbour two - a setup that has allowed astronomers to accurately 'weigh' the larger one.

The smaller black hole, which weighs about 100 million Suns, orbits the larger one on an oval-shaped path every 12 years. It comes close enough to punch through the disc of matter surrounding the larger black hole twice each orbit, causing a pair of outbursts that make OJ287 suddenly brighten.

General relativity predicts that the smaller hole's orbit itself should rotate, or precess, over time, so that the point at which it comes nearest its neighbour moves around in space - an effect seen in Mercury's orbit around the Sun, albeit on a smaller scale.
Bright outbursts

In the case of OJ287, the tremendous gravitational field of the larger black hole causes the smaller black hole's orbit to precess at an incredible 39° each orbit. The precession changes where and when the smaller hole crashes through the disc surrounding its larger sibling.

About a dozen of the resulting bright outbursts have been observed to date, and astronomers led by Mauri Valtonen of Tuorla Observatory in Finland have analysed them to measure the precession rate of the smaller hole's orbit. That, along with the period of the orbit, suggests the larger black hole weighs a record 18 billion Suns.

A couple of other black holes have been estimated to be as massive, but their masses are less certain, says Valtonen. That's because the estimates were based on the speed of gas clouds around the black holes, and it is not clear whether the clouds are simply passing by the black holes or actually orbiting them.

But Tod Strohmayer of NASA's Goddard Space Flight Center in Maryland, US, says he is not convinced that Valtonen's team has really measured the mass of the large black hole in OJ287 accurately.

That's because only a handful of the outbursts have been measured with high precision, making it difficult to determine if the precession scenario is responsible for the outbursts. "Obviously, if subsequent timings continue to agree with the model, then that would provide further support," he told New Scientist.
No limit

Just how big can black holes get? Craig Wheeler of the University of Texas in Austin, US, says it depends only on how long a black hole has been around and how fast it has swallowed matter in order to grow. "There is no theoretical upper limit," he says.

The new research also tested another prediction of general relativity - that the black holes should spiral towards each other as they radiate energy away in the form of gravitational waves, or ripples in space. This radiation affects the timing of the disc crossings and their accompanying outbursts.

The most recent outburst occurred on 13 September 2007, as predicted by general relativity. "If there was no orbital decay, the outburst would have been 20 days later than when it actually happened," Valtonen told New Scientist, adding that the black holes are on track to merge within 10,000 years.

Wheeler says the observations of the outbursts fit closely with the expectations from general relativity. "The fact that you can fit Einstein's theory [so well] ... is telling you that that's working," he says.

The research was presented on Wednesday at a meeting of the American Astronomical Society in Austin, Texas, US."

The equations presented by the OP only refer to a "condition" that can be mathematically described by a dormant black hole. Time simply does not play a part in describing the condition.

Observation indicates that black holes can grow and feed indefinitely which also indicates a variation in space/time somewhat proportional between the core of the black hole and the event horizon.

String theory would indicate that a true singularity could not exist at the core. Perhaps the reason for this is that time slows as density increases to a point where further movement takes infinitely long.

Einstein's theories state that time and space are inseparable.

I'm still not convinced that time stops. If a human being could survive in a black hole, I am fairly certain he would continue to age. The aging process might be slowed because of the gravity's effect on electro-chemical processes, or he would just plain die. Point is, time always moves forward. If it did not, then black holes could not grow in size at all....the mass asborbed would not create any progression which is what time is.

Now, I also do not believe that the mass of a black hole can be adequately measured. This is because the gravity super-heats anything being pulled in. Hence, meteors, meteorites, dust, asteroids, etc. lose density as they transform into gas. Because of the lesser density of gases, a black hole may increase in size and mass while the core of the black hole stays relatively constant. This super-heating may transform elements into iron eventually which might add to the core, but gases particles have a much lower mass, thereby slowing their acceleration due to the pull of gravity.

Because the gravity of a black hole is so strong, and can increase with additional mass, I still believe that eventually the core will distintegrate or degrade at some point. Perhaps this is in a manner similar to a nova, or perhaps it is more of a chemical interaction between the iron core and the surrounding gases. The point here is that eventually the core will lose density without losing mass, and that will lead to a decrease in gravitational pull. Once that weakens enough - a process that takes longer than man has existed - then light can once again escape, revealing a massive star in place of the black hole, one that burns very brightly due to the super-heated gases that had always been present.

I'm soooo glad we have some really intelligent people on here because this is way over my head....

A human could never survive the tidal effects of a black hole. You would be accelerated at a different rate all across your body tearing you apart.

The "hole" actually falls towards the core faster than the speed of light which is why light cannot escape. In that situation, time may have no meaning for those objects on their way to the core.



The mass of a black hole can be accurately measured by knowing the orbital effect on a known object (refer to my post above). Superheating an object does not change it's mass, only it's temperature.

Density has nothing to do with mass, nor does being a gas. Entry into a black hole may or may not briefly cause ions to combine but since the gravitation field already exceeds that of a neutron star, no atoms would remain for long. Even the neutrons are crushed. Gases would fall towards the core at the same Statistical speed as any other element. If tremendous heat is present, iron would simply vaporize anyway.



Black holes can evaporate by producing Hawking Radiation. The small ones evaporate quickly and the large ones last an incredibly long time. The core does not "degrade" or react in any kind of chemical way at all since electrons no longer exist. Given time (and a lot of it) if the black hole can evaporate down to about 1,000 tonnes, the rest of the mass will explode into one bright flash.

The core could never turn into a star because stars are balls of burning hydrogen and a black hole contains no hydrogen. There would be no superheated gasses present otherwise the black hole would be feeding and therefore gaining mass instead of evaporating.

http://casa.colorado.edu/~ajsh/hawk.html

I am a proponent of String Theory, M Theory and super symmetric theory. I think they offer the best explanations of how the universe is actually structured and functions. Although the theories are untestable at the moment, intuition, logic and some high mathematics makes these theories plausible. However, its almost as if the more we find out about black holes, time, The Big Bang, etc., the more we discover how much we really don't know. There are so many different equations that can be inserted into a myriad scenarios that anyone at this point could be right about anything. We have only recently discovered that not only is there a massive black hole at the center of the Milky Way (our galaxy), but there may also be a black hole at the galactic core of every galaxy in the known universe. Do galaxies form around black holes or do black holes produce galaxies (the old chicken or the egg conundrum)?
I disagree with one gentleman said earlier about always moving forward in time. I think the only thing linear about time is our perception of it. Our limited 4D experience only allows us to perceive time as going forward, just as we are unable to experience the other Planck scale-sized dimensions to our physical reality. The universe is made of circles...why not time? Are time and space not the same fabric? Hypothetically speaking, if you could walk around the universe would you not at some point end up where you began?

Human in black hole: I said "if", meaning we are making the assumption he could. Of course, man can't survive in one. It was used to illustrate a point.

Super-heating: Changes its density, spreading out particles. Each particle is of smaller mass, though group mass may not change. Furthermore, super-heating can spark fusion which does change mass. It's how stars work....fusing element gas into a denser, heavier gas from hydrogen to ultimately iron. If iron vaporized, then a black hole could not even exist. They are formed from when a star develops a massive, dense iron core whose gravity creates a shockwave causing the star to explode (a nova).

Evaporation: The existence of massive black holes suggest that they can indeed acquire mass and grow. Otherwise they would develop from stars so gargantuan that light would not be able to escape them at all....and that throws the entire theory of how black holes are created out the window. The core that forms a black hole is much, much smaller than the star that created it.

Mass the size of 18 billion suns for a black hole (from the article)? The largest stars only have 150 times the mass of the Sun, and they are the ones that create black holes in general. That definitely means black holes acquire mass. It also suggests that the calculation of its mass is wrong since it's overall density must be low compared to many large black holes.

Secondly, in the link provided, the bottom of the article even mentions that evaporation begins only after accumulation of mass stops. In other words, black holes can reach a saturation mass where they can absorb no more and begin to leak. That saturation point appears to be relative to the size of the black hole, which means it is probably related to overall density.

I am sure there probably is some form of evaporation and that is a form of degradation, just like radioactive isotopes have a half-life due to radiation. As fusion takes place - sparked by high heat - there is some matter lost as "evaporation". This would happen near the edges of a black hole, and the energy release could be enough for it to escape gravitational pull. However, Hawking's theory is far from proven.

You are dead wrong about mass, density and gases simply by their definitions.

Gases are one of the three phases of matter: solid, liquid, and gas. These phases are defined by density.

Density is mass per volume. Simple calculation.

Gravity is the rate of acceleration at which a smaller mass is pulled towards a larger mass.

Mass is the key to a black hole's entire existence. A gas cannot enlarge the core unless it becomes more dense by some sort of process like fusion. Sooner or later that accumulation of mass must lead to the death of a black hole. All black holes are so far from us that we are looking into the past, long before the time of recorded history. Therefore, black holes we are tracking may not even exist anymore - we just haven't witnessed it yet.

Your point is incorrect. You do not know that time moves forward in a black hole. This is one of the issues with "physics breaking down" at the core of a black hole.



Group mass does not change which is what allows us to calculate the mass of the black hole accurately. Mass is directly proportional to gravity and gravity can be (and is) directly observed.

While we don't know the physics of the working of SOME of the processes which occur deep into the black hole at pressures and densities beyond our current physics, we do understand them quite well up to that point. The process of fusion, vaporizing iron, etc. are well within our level of physics and do not exist in the scenario you describe, do not change density and have no effect on mass whatsoever. Your statement about a black hole not existing if the iron could vaporize is simply bizarre and holds no meaning. Virtually every concept you presented regarding this matter is incorrect.

Stars burn hydrogen to form helium. Helium is burned at a later stage to make carbon, calcium, etc,. The end of the line in fusion in the "normal" life of a star is the fusion that creates iron. As the life of the star ends, with sufficient mass, the star implodes with all mass concentrating at the core. Depending upon the mass of the star several things can happen.

The matter is crushed squeezing the electrons into the protons creating neutrons and a neutrino. The neutrinos rebound outward creating a shockwave that blows the star to smithereens. Depending upon mass, the explosion can cause a supernova to continue the process of fusion creating all the elements heavier than iron. This is where all the heavy elements on Earth came from.

Depending upon mass, the explosion can leave behind the remnant of the star composed of neutrons (a neutron star) or with more mass create a black hole. The physics of what happens up to and somewhat past the formation of the black hole are well understood. The deep inner workings of the black hole are the mystery. Relativity and quantum mechanics only have limited application. String theory may be the answer but the math hasn't been worked out.



With all due respect, the above statement doesn't mean anything.



The largest black holes are located in the center of galaxies. They are formed during the formation of the galaxy and are all many, many times larger than what you are calling a "typical". The calculation of mass from orbital date is Newtonian in it's simplicity and accurate to a very high degree. Your statement (and others) would indicate that you have no formal training in physics since you are incorrect on the simple facts. An object's mass can be calculated by the speed and distance of the objects about which it is orbited.



As I stated in my previous post, evaporation can occur but almost any acquisition of new mass with cause growth, not shrinkage. There is nothing in the posted like that would indicate any form of "saturation" nor any limit to the size and mass. There is no "saturation point" and fact that density in a black hole approaches infinity is what make the modern physics unworkable.



You obviously have no formal education in physics while I have advanced education in same. The joy of the internet.

The three phases of matter do not exist anywhere near the core of a black hole. We are describing forces much greater than those which create neutron stars.

The core of a black hole is generally referred to as a singularity due to the fact the density is meaningless.

Gravity is the time/space distortion created by the presence of mass; any mass. Group masses are attracted to the centroid of the group mass. A common misconception is your statement. The truth is that the larger mass is equally attracted to the smaller mass.



Sad.

All matter entering a black hole will be rapidly broken down. A gas will first be ionized then the nucleus will be crushed. A solid will be torn apart into gas by tidal forces, ionized, then crushed. Liquids would be vaporized then treated as a gas.

The growth of atoms into larger atoms may occur for an instant ( just after entering the event horizon) if they happen to bump into another nucleus but soon are torn apart.

Electrons, protons, and neutrons cannot exist near a black hole because the particles are torn into quarks and neutrinos so electrons, protons, and neutrons no longer exist. The processes you mention require these particles to exist. Therefore the processes you mention cannot exist.

Black holes are observed from the age of a few years to almost the time since the big bang. Your comment about their life would indicate that you don't even read casually about science. Actual science is fascinating. You shouldn't make it up.

"NASA'S Chandra Finds Youngest Nearby Black Hole


WASHINGTON -- Astronomers using NASA's Chandra X-ray Observatory have found evidence of the youngest black hole known to exist in our cosmic neighborhood. The 30-year-old black hole provides a unique opportunity to watch this type of object develop from infancy.

The black hole could help scientists better understand how massive stars explode, which ones leave behind black holes or neutron stars, and the number of black holes in our galaxy and others.

The 30-year-old object is a remnant of SN 1979C, a supernova in the galaxy M100 approximately 50 million light years from Earth. Data from Chandra, NASA's Swift satellite, the European Space Agency's XMM-Newton and the German ROSAT observatory revealed a bright source of X-rays that has remained steady during observation from 1995 to 2007. This suggests the object is a black hole being fed either by material falling into it from the supernova or a binary companion."

Metalwing is spot on in everything he has said.

The reality of the situation is that no one really knows what a frame of reference would be like at the center of a black hole.

I have not read the actual paper the link is based on, becuase I can no longer access my colleges resource site. However I would remain skeptical for no other reason that we cannot test the conclusions, nor would we have any real concrete way to make observations that would conclusively back up the idea.

I think its a cool idea, I think its probably wrong. Black holes evaporate, this to me indicates that change occurs, even if only at the Quantum scale and while the frame of reference at the center of a black hole may be infinitely red shifted I would not wager if that meant time was infinitely slowed compared to a frame outside the hole.

Metalwing is right, the reason physicists say that physics breaks down at the heart of a black hole is becuase the maths we use break down . . . that is it.

Infinities in physics yield little and most often no meaning. We tend to say, ya did it wrong, if you get infinities and were looking for a discrete answer.

Please do not get me started on string theory, it is a bottom up approach that has tried and failed to give good predictors for 30 years. The cosmological constant being one of them. Yet it remains popular . . .

My specialty is radiology so do not take this as I am some kind of specialist in cosmology and strings, I am not but I do hold opinions based in facts. The facts right now are more theorizing and less realizing when it comes to the hearts of black holes.

I find it hard to believe that a singularity would contain no hydrogen. Hydrogen is a background within the universe. As such it would stand to reason that an object which feeds on the matter arround it would of a necessity 'pull' in also a corresponding ammount of hydrogen to the ratio of hydrogen that surrounds it.

It contains no hydrogen becuase the forces are so great as to rip the protons, neutrons and electrons from each other.

Is it not also possible that as an atom approaches a singularity its 'attraction' changes reciprocol to its distance to the 'altered' gravitational attration of the singularity...

in such a way that it's structure does not 'change' by 'ripping' but by an energy level change (acceleration in either 'time' or 'speed') causes it to emit (instead of an electron) x-rays?

(curse english - it can not fully explaine what I am thinking).

Atom that is accelerated by changing state emits an electron.

Atom that is changing state by acceleration of gravity to near perfect E=MC(squared) may emit x-energy instead of sheding electrons.

(and my english still is lacking)

I am sure that will reslult in more insults on my intelligence.