An artist's conception of stars moving in the central regions of a giant elliptical galaxy that harbors a supermassive black hole.
Image: Gemini Observatory/AURA artwork by Lynette Cook
Scientists have discovered the largest black holes yet, and they're far bigger than researchers expected based on the galaxies in which they were found.
The discovery suggests we have much to learn about how monster black holes grow, scientists said.
All large galaxies are thought to harbor super-massive black holes at their hearts that contain millions to billions of times the mass of our sun. Until now, the largest black hole known was a mammoth dwelling in the giant elliptical galaxy Messier 87. This black hole has a mass 6.3 billion times that of the sun.
Now research suggests black holes in two nearby galaxies are even bigger. [Photos: Black Holes of the Universe]
The scientists used the Gemini and Keck observatories in Hawaii and the McDonald Observatory in Texas to monitor the velocities of stars orbiting around the centers of a pair of galaxies. These velocities reveal the strength of the gravitational pull on those stars, which in turn is linked with the masses of the black holes lurking there.
The new findings suggest that one galaxy, known as NGC 3842, the brightest galaxy in the Leo cluster of galaxies nearly 320 million light years distant, has a central black hole 9.7 billion solar masses large. The other, named NGC 4889, the brightest galaxy in the Coma cluster more than 335 million light years away, has a black hole of comparable or larger mass. Both encompass regions or "event horizons" about five times the distance from the sun to Pluto.
"For comparison, these black holes are 2,500 times as massive as the black hole at the center of the
Milky Way galaxy, whose event horizon is one-fifth the orbit of Mercury," said study lead author Nicholas McConnell at the University of California, Berkeley.
Astronomers had suspected that black holes more than 10 billion solar masses large exist, based on light from quasars, cosmic objects from the early universe that are no more than a light year or two across but are thousands of times brighter than our entire galaxy.
The light of quasars is thought to come from matter driven to incandescent brightness as it spirals at high speeds into supermassive black holes. This is the first time scientists have detected black holes approaching such theorized giants in size.
"These two new supermassive black holes are similar in mass to young quasars, and may be the missing link between quasars and the supermassive black holes we see today," said study co-author Chung-Pei Ma, an astrophysicist at the University of California, Berkeley.
The researchers suggest these relatively dim black holes may be the aged remnants of quasars — "their central black holes are no longer fed by accreting gas, so have become dormant and hidden," Mai told SPACE.com. "The boisterous quasars may have passed through a turbulent youth to become quiescent giant elliptical galaxies."
This pair of black holes is 1.6 to 4.6 times more massive than one would predict from their galaxies, based on details such as the brightness of the bulges at their centers. These findings suggest that black holes may grow differently in large galaxies than in small ones.
"We know that bigger galaxies are made by mergers of smaller galaxies, and during this process, the black holes at the centers of the smaller galaxies can merge to form bigger black holes," Mai said. "But black holes can also grow by being fed by gas in their vicinity. It's a bit like asking, 'Are taller children produced by taller parents or by eating a lot of spinach?' For black holes, we are not sure."
See what we're tweeting about
14 Comments
Add CommentUnder the title, "objects 9.7 solar masses large or more" should read "objects 9.7 billion solar masses large or more"
Reply | Report Abuse | Link to thisI wonder if these unexpectedly huge black holes have any bearing on the rationale for dark matter. If the black hole's gravitational field extends far beyond previous estimates, does it affect the rotational motion of visible stars differently than was assumed?
Reply | Report Abuse | Link to thisGenerally, the effective mass of supermassive galactic black holes is a small fraction of the galactic mass estimated from the luminosity of observed matter.
Reply | Report Abuse | Link to thisConversely, the mass attributed to dark matter is often 6-10 times the mass estimated for galactic luminous matter.
Moreover, the requirement for galactic dark matter is inferred by the rotational velocities of their peripheral objects, which generally do not diminish in accordance with Keplerian rotation curves derived from observations of the Solar System.
While any even larger central mass might account for the excessive velocities of peripheral objects, in that case objects within the interiors of galaxies would rotate much faster than observed.
In summary, the perceived requirement for dark matter to explain the rotation of galaxies was artificially produced by the invalid application of empirical 'laws' of planetary motion within the Solar system to the dissimilar vast distributions of massive objects comprising spiral galaxies. Not to say that dark matter cannot exist anywhere, but a few dozen research reports indicate that it, and modified gravity, are not necessary to produce the observed dynamic motions of spiral galaxies.
This is explained in a brief commentary, "On not being the first to discover no galactic dark matter", http://www.sciencewithoutfiction.com/uploads/JDwyer.PDF
It also includes references to research reports describing methods of galactic gravitational evaluation that explain the motions of spiral galaxies without requiring galactic dark matter or modified gravity. More recently, please see: Feng & Gallo, (2011), "Modeling the Newtonian dynamics for rotation curve analysis of thin-disk galaxies", http://www.raa-journal.org/raa/index.php/raa/article/view/858
Regarding your question about the gravitational influence of supermassive black holes, the lead author of the described study was quoted:
Reply | Report Abuse | Link to this"For comparison, these black holes are 2,500 times as massive as the black hole at the center of the Milky Way galaxy, whose event horizon is one-fifth the orbit of Mercury."
Supermassive black holes are identified by the extreme orbital velocities they produce for neighboring stars. Even these supermassive "monsters" have little if any direct gravitational effect on the majority of a galaxy's objects - their effects are quite localized in relation to the scales of galaxies.
Sorry, dark matter is not just a theoretical construct and its effects have been observed:
Reply | Report Abuse | Link to thishttp://arxiv.org/PS_cache/astro-ph/pdf/0309/0309303v2.pdf
There probably needs to be some refinement with mutual gravitation accounting for some properties of galactic motion like you highlighted, but Dark Matter is here to stay.
Sorry, dark matter's effects have only been inferred by observational interpretations. Just to point out a few issues that are not usually recognized, the 'Bullet cluster' imagery described by your reference shows convincing blue blobs representing the two colliding clusters' dark matter as inferred by a very complex process of statistically identified minute weak gravitational lens effects. Please see:
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Weak_Gravitational_Lensing
Moreover, in the case of colliding galaxies, regions identified by weak gravitational lensing also contain the respective cluster's visible galaxies. The requirement for dark matter to produce the weak lensing effects is rationalized by a perceived discrepancy between the sum galactic mass, estimated using very generally established galactic mass/light ratios, and observed gravitational effects.
The methods used to infer the presence of dark matter in galactic clusters is so complex that I certainly have no aspirations for dissuading all those who have accepted research methods established over the past several decades.
I only argue that the justification used to initially establish the requirement for dark matter, to compensate for incorrect gravitational evaluations of spiral galaxies, is not valid. I think if you read the research reports I reference they provide gravitational evaluation methods that fully explain the rotational characteristics of spiral galaxies without dark matter or modified gravity.
I make no futile arguments against dark matter that is so commonly thought to exist anywhere else in the cosmos, including within the intracluster medium of galaxy clusters, or that it does not represent the vast majority of mass in the universe, etc., etc. I do accept that dark matter is firmly entrenched within the physics community and, as you say, 'here to stay'. However, as a layman, I am free to express my opinion...
Since all these are just theories, here is another theory: Did you ever think that black holes are just roadways between Universes and Galaxies like a hollow drain pipe is between your roof and your floor? The bigger the drain pipe, the slower the spin at the other end. Could that also explain why some galaxies and stars seem to be spinning faster than others? I don't think that a black hole is like a Star Trek transporter that disassembles matter at one end and reassembles it at the other end. I think they are like water slides at a park...water, carrying people, comes in one end and shoots out the other. The person had a fantastic ride and is still alive. Since humans may never be able to prove or disprove this theory, I'll consider my theory the most correct and wait a million years until it can be proved.
Reply | Report Abuse | Link to thisThe largest black in the smallest size is the Human Brain
Reply | Report Abuse | Link to thiswith its 100 billion neurons some having up to 50.000
synapses in 1.500 kgs .(even women with their smaller brain size have as much, contrary to what machists pretend)
Thought is faster than ligntning
Cagliostro
Think it over
One of the links in this article leads to a website that raises the question of the infinite density of matter inside a black hole, the singularity having compressed the matter to a point of having no dimension or size at all. I have the hunch that infinite is just a concept or a construct of our mind, that doesn't exist at all in the material or real world, and that we use even when we know that neither our mind, nor the biggest computer we may ever build, can simulate or handle anything being "infinite". For some, however, it seems that matter can't be compressed below the size of strings, strings being the smallest block sub-atomic and atomic particles being built of, and thus all matter being formed by strings. Some old african cultures say that matter is built of vibrations, and some seem saying that strings do vibrate. If it's right that nothing can be compressed below the size of strings, this opens the possiblity that the size of the singularity inside a black hole, and perhaps its properties and behaviour, may be different depending on the amount of matter inside the black hole. Somebody has more professional and broad knowledge of this ?
Reply | Report Abuse | Link to thisAs stated in http://en.wikipedia.org/wiki/Black_hole#Singularity
Reply | Report Abuse | Link to this“At the center of a black hole as described by general relativity lies a gravitational singularity, a region where the spacetime curvature becomes infinite. For a non-rotating black hole this region takes the shape of a single point and for a rotating black hole it is smeared out to form a ring singularity lying in the plane of rotation. In both cases the singular region has zero volume. It can also be shown that the singular region contains all the mass of the black hole solution. The singular region can thus be thought of as having infinite density.”
However, Quantum Mechanics forbids wavelike particles entering a space smaller than their wavelength.
It is stated in http://en.wikipedia.org/wiki/Neutron_stars
“A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger mass than protons. Neutron stars are very hot and are supported against further collapse by quantum degeneracy pressure due to the Pauli exclusion principle. This principle states that no two neutrons (or any other fermionic particles) can occupy the same place and quantum state simultaneously.”
Neutron star material is thought to be among the densest forms of matter possible. Their inner core is most simply thought to consist of a quark gluon plasma, although its actual composition is uncertain. This poses a problem for black holes, since no denser forms of matter could be contained within a dimensionless singularity.
I propose the simplest solution to this dilemma and a general mechanism to produce it: black hole singularities do not contain any matter. Enormous amounts of massive material could not possibly be contained within a dimensionless singularity. Moreover, black holes ingesting matter are observed to eject enormous volumes of fundamental particles from relativistic polar jets.
Reply | Report Abuse | Link to thisIt seems that (atomic) matter ingested into black holes must be accelerated to nearly the speed of light, and that its incidental collisions would necessarily decompose the massive material into fundamental particles, likely stripped of their mass, similarly to particle collider experiments. Through some undetermined complex mechanism these particles may be ejected, producing the observed relativistic polar jets. The extracted particle mass may be retained within the black hole as gravitational energy, now redirected to a singular focal point.
This general mechanism can explain how gravitational singularities can exist without containing dimensional material, and the production of observed relativistic jets by active black holes. Black holes may exist simply as locally contracted spacetime: gravitational energy directed to a dimensionless singularity.
The words "black holes" are not correct and just "big masses" should be used. Namely black holes are based on the assumption that the general theory of relativity is correct. This is not so as Vasily Yanchilin argues in his book The Quantum Theory of Gravitation (2003) by explaining with the principle of least action that light curves towards mass: the photon tries to find a path with as big steps (oscillations) as possible and a minimum number of these. All scientists agree that near mass the unit of length becomse smaller and thus the path longer. Einstein thought that near mass the second has longer duration while Yanchilin maintains that time passes swifter there. The latter is in accordance with the fast processes at the Big Bang. If Einstein's theory is correct then the photon will take a hyperbola route (seen from a distant observer; in own geometry it just follows a straight path: see the book for more details or if not at hand www.janjitso.blogspot.com, also for short introduction to the new gravity theory that is in agreement with quantum mechanics. It is well known that rays from Mercurius follow the parabola path, curve towards the sun.
Reply | Report Abuse | Link to thisEinstein himself only took constancy of propagation of electro-magnetic waves in vacuum only as a temporary hypothesis when quantum mechanics did not yet exist. Reflect on the words electro, magnetic, waves to understand that the speed of light is not independent of everything else in the universe.
Yanchilin is busy with atomic clocks at different heights to see where the second runs faster, but the core of atoms is not quite at rest and therefore it influences the electrons around. That's why elsewhere 500 atomic clocks are scheduled in line to fix new time standard. Imagine laser rays at different heights, closer and farther from the Earth mass and thus with different frequencies, that are passing and not passing prisms while the lengths of the opposite sides of the thus formed triangles are measured. At a fairly far distance to get measurable differences. However the unit of length changes also, etc. So first theoretical research is necessary to see whether the experiment can give results.
The redshift of sunlight is explained according the theory of relativity as caused by slower second at the sun and by overcoming gravitational attraction of the sun. Yet not the sum of both is measured. Yanchilin gives a new, interesting explanation.
I should add that light follows the optical shortest path. For better understanding Yanchilin presents a drawing with between points A and B a convex line, a straight line and a concave line and below a mass, all seen from the bottom of the paper. If there is no mass the photons follow the straight line. When mass is passed the convex route is followed as here the biggest steps (lowest frequency) and the smallest number of steps (unit of length bigger) can occur. In the general theory of relativity light follows a straight path while space is curved. This theory gives in several cases rather good approximation when factors vary little. But in the case of giant masses it gives totally wrong results and think of the enormous concentration of the universe at the Big Bang which is understood to proceed with maximum speed.
Reply | Report Abuse | Link to thisNow about discussion: I did not give my own opinion but quoted the results of a serious researcher. Then the authors of this article should respond whether they still will stick to "black holes" instead of just giant masses. To get a serious paper the editors of Scientific American should not be negligent about the new theory.
If the stuff is not understood well then reading on www.janjitso.blogspot.com may help.
So called Black holes are mathematical artifacts.
Reply | Report Abuse | Link to thisThey don't exist in real. There is another way to
explain stars orbiting at the galactic center.
See cosmicdarkmatter.