Black holes Definition and 1000 Threads

I read in a book that since the area of a black hole increases, the entropy increases, so black holes are consistent w/ the second law of thermodynamics. So...I have a really stupid question on black holes and the second law of thermodynamics: Consider an ideal gas of non-interacting...

I know that black holes are still not entirely understood, but I do know that it's generally accepted that they emit Hawking radiation. But I've also heard that the gravitational pull of a black hole is so strong that nothing can escape, "not even light". So how is it possible that Hawking...

I have to write a research paper on a topic of my choice for physics class, I chose black holes simply because they interest me and it was one of the few topics unchosen. Can anyone with more scientific intellect then myself provide some insight as to how black holes relate to physics? Just some...

To my understanding, as an object approaches the event horizon of a black hole, the light that is seen by a relatively static observer slows down more and more until the light is eventually "trapped" on the event horizon, making it appear to the observer as though the object is standing still...

It is well-known that associated with the Kerr solution which represents a rotating black hole, there can be a region of space-time where there are loops in space time (non simply connected paths which are navigable in principle). If this is so, it breaks causality and permits time travel in...

Hi everyone. I have a very keen interest in physics. Unfortunately at school I was made to do a combined qualification in science which didn't allow me to pursue what I was interested in most. I still try and read and understand what I can about physics and cosmology... but one thing has...

Simple enough question. I know there are two types of black holes; the type formed after a star collapses in a supernova and the supermassive variety like the one at the center of the milky way. If a star continued to grow by swallowing up other stars and solar systems is it possible that at a...

Hawking and others suggest that it is a very special deal that macroscopic black holes lose quantum information, but I only partially agree. It is clearly important that they do not preserve most quantum numbers - black holes may be a way to break a lot of conservation laws of particle physics...

I think we're all familliar with the old "What if you fell into a black hole?" Event horizons, time dilation (I think is the right term), and spagettification. There is however one thing these thought experiments never seem to cover that I'm really curious about. As I understand this...

If neutrinos can move faster than light speed, then can they escape from a black hole? If so, then would the life of a black hole be reduced?

http://whoknew.news.yahoo.com/who-knew/black-holes-27425876.html

Hello! I just want to start off by saying that I am no physicist or astronomer, so my apologies if my questions are really basic lol (although I am an engineer so I do have some technical background). I am very interested in it though, and I had some questions that I was hoping someone could...

Am I correct in saying that in theory Time, Matter and presumably Energy are compressed to a singularity at the centre of a black hole? If that is so then wouldn't they be "transported" back to the state and position they were in at the very beginning of time. In other words the instant of...

Talking about the big bounce and black holes in another thread made me wonder about the life span of black holes, especially in the heat death scenario. If the U went through heat death, does that mean that black holes would also exhaust their energy? Do black holes die, and if so, what...

It is my understanding that time within black holes is slowed down incredibly, and all of the mass is found within this slowed down area. How then could a black hole move if time is slowed down so much (possibly infinitely)? Shouldn't this slowing of time also reduce the speeds of the mass...

Can the amount of space/time warped by a black hole be measured and if so, where can I find measurements of previously measured black holes?

As I currently understand it from the point of view of an observer falling into a black hole it takes a finite time to cross the event horizon and reach the singularity. From the point of view of a far away observer the person falling into the black hole never actually crosses the event horizon...

A thought experiment I have been thinking about this for twenty years and I would like to hear your opinions. It relates to black holes, dark matter, the expansion of the universe, and unifying theories. This is very simple and beautiful to me. Forgive my lack of formal training, my goal...

Hello, I'll try to explain this as well as I can... I was watching NOVA's special on The Fabric of the Cosmos and the segment on how information is both lost in the black hole and stored on the surface got me wondering "Is there a limit to how much information can be stored on the surface...

I don't like the idea of anything crossing the event horizon of a black hole from any observer's view point. The closer something gets to the event horizon, it either appears to slow down, or the event horizon appears to stretch and move further away. How can anything cross it? For this...

If gravity is a distortion between space and time, then how come black holes are formed, only the surface of an object should then exert gravity, right?

what happens when two black holes collide?

what is the difference between a neutron star and a black hole?

Has anyone figured out or tried this: It seems to me that since light is bent by G fields, that looking close enough to the side of a black hole, some of that light near the event horizon may have escaped its G field after its trajectory has changed significantly... possibly redirected enough...

Can anyone point me to a journal article that describes, mathematically or otherwise, how those jets shoot from the poles of some black holes with accretion discs and AGN. Also, if you will forgive the additional question, is there any reason why the physics that describe the ejection from...

Hi. So, as title says, how can black holes radiate if nothing can escape from them?

Suppose there exists a black hole with a large + electrical charge. The escape velocity for any given particle will depend on the net force on it, gravitational + electrical. It seems logical that the more positive a particles charge the lower its escape velocity will be from any given point. If...

Apparently VY Canis Majoris is 30–40 solar masses, also there's R136a1 which is 265 solar masses. How do they remain stars with all that mass?

According to theory of black hole radiation, black holes are expected to emit a thermal spectrum of radiation, and thereby loss mass, owing to the E=mc2 equation. Well, everything was clear to me till I got to the last point. why should there be loss only in mass?? couldn't the mass be same and...

Hello friends! Forgive me, I have another question for you physicists. We see those active galactic nucley which show enormous emission phenomena, so: How can we know that responsible are gigantic black holes and not white holes? I suppose we guess it, becouse we have some theory on the...

What would happen? Would the result be a non-rotating black hole? During their collision when their ergospheres overlap, would it generate an area where nothing could move in either direction along the plane of rotation? Also, since the force of their gravitational pull would be the same, would...

Black holes are believed to be scattered throughout the universe. These ultra-dense bodies have a gravity field so dense that nothing, not even light can escape. If these bodies are able to consume everything that enters its event horizon than over the billions of years that the universe has...

Hi Guys, Just a thought, if a job of a black hole is to suck everything in it's surrounding to nothing-ness. Then why are the there examples of black holes with jet streams flowing away from their axial poles? Apparently the Earth's gravity field is weaker at the equator, so why does...

Whenever I see any image of a black hole or in television or anywhere, I found there is a ring of light around the black hole. In discovery channel, I heard them saying that scientist found rings of light in space which had black region inside it. It was also one of the evidence with the help of...

Where can i read about the solution of Einstein equations with spherical symmetry in tetrad formalism?

It seems like black holes could just as easily be expelling the matter they rip up. Couldn't a black hole just be something that rips matter apart atom by atom and then blasts it back into space? In this case there wouldn't be a need for a singularity. Quasars are one example of how they...

Have we ever observed microscopic black holes in the LHC?

I was playing around with some equations and I found a reason why I think micro black holes cannot exist. This proof requires a few assumptions which I have tended to find to be a scientific consensus. They are the following. 1) The smallest mass a black hole can have is the Planck mass which...

When it comes to dark matter; Has the mass of the super-massive black holes residing at the core of every galaxy been taken into consideration? Could the total mass of all black holes account for the missing mass in the universe?

A description of problems with the common understanding of black holes by this layperson: I have been contemplating black holes since I first heard about them at a lecture series by the then director of the Griffith Observatory in Los Angeles, by Dr. William J. Kaufman circa 1964. It seems...

According to a recent published article, Physicist Leonard Susskind feels, along with Niels Bohr, that rather than try to come up with a mental picture of what objective reality is, scientists should limit themselves to creating hypotheses and testing them empirically. Susskind contends that a...

Is Schwarzschild radius trying to state the gravitational field on the event horizon of a black hole? If not, what is it trying to state? Can you give me a example using his formula to figure out the gravitational force of a black hole in the event horizon? Do you have any links I can...

I didn’t believe it when I first heard it. I don't know how to reconcile this fact with what I understand about the known laws of physics. It appears to be one of the grandest mysteries I can think of. I understand that most of the universe is empty space but zero volume is different. Anyways...

"Black Hole Masses are Quantized," Gia Dvali, Cesar Gomez, Slava Mukhanov, http://arxiv.org/abs/1106.5894 There is a nontechnical summary on the arxiv blog: http://www.technologyreview.com/blog/arxiv/ , along with some inflammatory and uninformed speculation about safety at the LHC, including...

Hello to all physics community! I have a question concerning black holes. Are black holes, real holes? And which is the difference between black holes and wormholes?

I have read that it is possible that primordial black holes could have formed in many different sizes, from micro black holes to hundreds of solar masses, my question is this. What is the smallest black hole that could survive from this time until now, without being destroyed by hawking...

In an earlier post I make the controversial suggestion that the universe was very heterogeneous in the early stages. I have another conjecture that goes along with that one. Please try to read this with a bit of an open mind. Imagine that there is an upper limit to the size of a black...

Could the primordial black holes that seeded the first galaxies have been formed from spacetime that never expanded below the critical threshold for black hole formation? If quantum jitters caused the variation in densities seen in the cosmic background radiation, could islands of higher density...

The news always depicts them as real http://www.bbc.co.uk/news/science-environment-13964767 But as far as I gather from reading this forum and wikipedia, black holes are always said to be "candidates" Has it been proven "beyond a reasonable doubt" that they exist?

From another post on this forum, we have an excerpt of Susskind's "The Black Whole War": To figure the increase in mass, let's figure the energy of the photon and then convert that to an equivalent mass. Photon energy is E = hf and if wavelength is R[sub]s/SUB], from v = f x...