Black holes Definition and 1000 Threads

so how are they actually created. i know it happens on a collapsing of a star due to the big gravity which it has, but what's the real physical concept behind it. it can't be just like everting your shirt, right? what do black holes concist of? or what are they? where does the matter...

I've been watching videos and reading about black holes and big bang and many questions puzzle me. But here's one that I don't really get it. How the big bang even started since it had all mass of the universe in it. Therefore its gravitational pull in itself would surpass any mass of...

From my limited understanding, black holes supposedly have "event horizons" where everything near them just falls inside the black hole and becomes nothingness, totally anhilated. If this is the case then how is it that black holes emit stuff, like radio waves? If they suck things in and then...

I was reading something about formation of black hole, and it was given that exclusion principle has a role in BH (Black Hole) formation. It read "when star become small, the matter particle get very near each other, and so acc. to Pauli's Exclusion principle they must have different...

I enjoy studying QM, but my knowledge of black holes is basically limited to the high school explanations as depicted below. As a body approaches the event horizon the gravitational forces on that body accelerate it to a velocity approaching c. The math implies that mass crossing the event...

http://arxiv.org/abs/0905.3170 In this paper we have recalled the semiclassical metric obtained from a classical analysis of the loop quantum black hole (LQBH). We show that the regular Reissner-Nordstrom-like metric is self-dual in the sense of T-duality: the form of the metric obtained in...

Please forgive me if I am posting in the wrong place, and also if this has been discussed before. Gravity is so strong in a black hole not even light can escape, Can the light be accelerated past c once inside of the event horizon? I know the universal answer that nothing can exceed c...

Hey guys, This may be a silly question. I saw star trek the other day, and I know it is science fiction but I was wondering...My understanding is that black holes are a region in space-time from which nothing can escape. However it seems like in the movie they are also used to travel through...

Questions: Gravitational redshift and black holes I have some questions: 1. What does gravitational redshift do to light trying to escape a black hole? Is the light destroyed? 2. And what is the physical cause of this redshift? (I’m not interested in equations and math, only the physical...

The reason I heard that black holes are black is because any light that trying to leave the black hole's gravity gets sucked in by the massive amounts of gravity. So this implies that light can curve or even reverse direction if enough gravity is present. If this is the case then what stops a...

I'm clueless.

The question says it all. Black holes have mass, and they have angular momentum. - Is the angular momentum an integer or half an integer? Or neither/both? - What happens when two black holes are exchanged? François

I read recently that magnetism plays an important role in cramming all that matter into a black hole. But how is it possible that magnetic force could escape a black hole, having an escape velocity higher than the speed of light, therefore an impossibility of matter(or energy) escaping?

It is generally accepted that light cannot escape a "black" hole because the singularity's gravitational pull is too strong for photons (or waves, or wavicles, or whatever) to achieve movement away from the singularity. Isn't gravity a warping of space? And isn't space a facet of a single...

Why can't light escape black holes? Isn't light as an electromagnetic radiation massless, thus not affected by gravitational pull? --

I read Wikipedia about black hole and interpreted it as such: that black holes exist all around us, most of them are very, very small. Suppose we have a drinking water glass (just suppose its mass is 10kg) hence at radius 1.48 E-26 m (far smaller than even the radius of an electron) there...

The short version: Is it possible to engineer anything useful with black holes in our universe? The long version: I'm working on making the backstory for a fiction I've been thinking about, and I'd like to get a better understanding of theoretical black hole physics for that story. The...

What I was thinking is that if dark matter particles don't interact electromagnetically or by nuclear forces then what is there to stop them coming arbitrarily close to each other thus forming microscopic black holes? And shouldn't we then be able to detect them by Hawking radiation? Does the...

I understand that it takes an infinite amount of time for an event horizon to form. Give this, if there are any black holes, they have been around forever. Are there good comological models that include 'forever', or is my premise wrong?

As far as I know, a black hole is a singularity in the space-time. The space-time becomes so curved that the geodesics can't get out, i.e., the gravitational field becomes so strong that information can not get out. OK! But what about gravitational waves? As far as I know, gravitational waves...

Hi, I was wondering how black hole's radiate energy and to be specific what the geometry of this radiation is. Can they radiate it planar, polar like a gamma ray burster, or something else? I'm not sure how far astrophysicists have gotten in terms of the theory of this, so please include all...

Hey guys, I got a question that is kind of bugging me.. Need your opinion on it. Here are my thoughts from my notebook that i wrote while i was at work :) Sorry for the loose and simplified language.. In the paper titled "Greatest Story Ever Told", Neil deGrasse Tyson states that little...

If gravitons exist, how can black holes emit them? It cannot be like Hawking radiation, which increases as the black hole gets smaller. The gravitational field grows larger as black holes grow larger. Also, would not the energy of the graviton decrease to zero (and its wavelength increase to...

blechman's statement: Gravitons are emitted FROM THE SURFACE of the event horizon (remember: gravitons are massless, and therefore move at the speed of light). THAT's what we see. There is NO information (gravitational or otherwise) that can escape from INSIDE the black hole. This is not a...

I had a conversation with a friend about Black Hole images. I showed him a picture of a black hole taken by the Hubble telescope shown here: http://hubblesite.org/newscenter/archive/releases/1995/47/image/a/ He claims that it's not a direct image of a black hole because we can't see black...

http://www.superstringtheory.com/blackh/blackh3.html the URL above says that black holes can decay, but I don't understand, if the black hole sucks in an antiparticle and the particle gets ejected in the opposite direction, doesn't the event horizon of the black hole stay the same? How does it...

I read that if an observer were to watch as another observer fell into the black hole, eventually observer A would see B stop before reaching the event horizon. I'm having a little trouble with this and have to questions about it. 1)If we turned an extremely powerful telescope at a black...

Are black holes studied in cosmology at all, by any cosmologists? Are there any cosmological theories that investigate quantum exchanges, or entanglement (I had a vague idea there were one or two). Is the subject not allowed at this forum, or is it that entanglement "goes in the quantum...

RE: Mass-inflation in rotating/charged black holes From page 42 'Evolution Problems of General Relativity' by Jakob Hansen www.nbi.ku.dk/english/research/phd_theses/phd_theses_2005/2005/jakob_hansen.pdf/ The above is also mentioned in- 'Developments in General Relativity: Black Hole...

peace upon u .. though it's a fantasy but it's a scientific one .. i've read about the generating energy from black holes the issue that: is such an extreme science fiction reachable ?? no doubt that wireless connection was a science fiction once upon the time .. but there was a...

Couple of questions here; I know they may sound dumb but here they go. I'm "new" with some questions, so be gentle. 1.) So, if a black hole has enough gravitational pull to pull in stars and what nots, and nothing can pull away from this force once it is to close, its consumed by the black...

Well, I'm currently reading The Black Hole War by Leonard Susskind, and one thing to me seriously doesn't add up. It says that when someone falls into a black hole, and observer from the outside would not see them fall into the singularity, but they would seem to stretch out and move slower and...

I was wondering about a question that popped into my mind recently -Let's say, theoretically, a device existed that could reverse the force of gravity somehow, to the point were it created antigravity. Since black holes are held together by their own gravity, pushing molecules closer than...

Hi, My name is Brandon, I am new here. My physics knowledge mostly comes from surfing the net, so I have a lot of gaps in my understanding. But i do love the stuff, and i try to stay open to it. Anyway, i know about dark energy and the expansion of the universe. and i guess the...

I am fairly ignorant in the area of cosmology, but I was wondering what the effect black holes have on other black holes may be.

Hello, i was studying kerr black holes and i think i can understand most of the theory behind it but i was wondering how can you detect black holes that are actually rotating?. I thought like sending two light rays from the same point (like gravitational lensing) but since the black hole is...

Wouldn't an object traveling close the speed of light decrease in length and increase in mass, effectively creating a black hole? I attempted to do the calculations, but I don't know how to calculate the Schwartzchild radius of an accelerating body. Do you find out what the radius would be...

Hello, I have the following question: Let as assume that wormholes can exist. What happens if an advanced civilization is able to construct a wormhole with one end on its own planet and the other end of the wormhole below the event horizon of a black hole? Will they be able to see what is...

It is my understanding that with the passing of time, space actually expands in size. In about 14G years, space will be twice its current size. What will this do to black holes (BH)? If a BH is in intergalactic space and has nothing to consume, if space actually expands, the density of the BH...

I'm a non-scientist - that watches way too many TV science programs - that is having trouble putting the pieces together. I am always hearing about how much visible matter is missing from the universe. I am also hearing about how (it is now believed) that every galaxy contains a massive...

If Dark Matter are particles that interact gravitationally, then what happens when/or if Dark Matter falls into a Black Hole? We would not "SEE" a Dark Matter accreation disk, but would we see any kind of radiation? Or would we see the mass grow? Thanks.

Information In the book “Black Holes and Time Warps” by Kip Thorne it is mentioned on pg 121 that Einstein didn’t believe that black holes existed so the thinking that black holes can exist didn’t come directly from his writing, thoughts, or how he interpreted his relativity theories. Because...

Hi I have few questions about charged BH. 1 I don't understand why the equations for the charged BH are different from BH without a charge. Why the gravitation, infinitely strong at the horizon, should 'care' about such minor additional forces like the electrical attraction/repulsion...

1. What are some specifics about black holes? 2. I've heard there's a supermassive one at the center of our galaxy--FACT or FICTION? Relevant websites, articles, etc. highly welcome! (I'm really interested in cosmology, obviously.)

Can BH be formed during star formation process? For instance, giant gas cloud or several collided clouds. In this case, can BH be created right after BB? Thank you.

Ok if this has been covered before if you could show me any links that would be great.. I was watching a program about time and how it appears to slow to a stop within a black hole... yet time can only be still if an object is frozen in time, bu a black hole moves meaning it is not frozen in...

so I read about this "theory" a while back, and I've been doing some thinking about it. The "theory" is basically just that since a black hole with the same mass/spin/charge as a fundamental particle would appear to be identical to that particle, it is possible that all particles are just black...

As I understand (?) it, if you want to observe something too small, the photons needed will have to be so energetic that a black hole will form. The question I have is: why would photons form a black hole, I thought photons were massless?

When people appear to be getting very confused about the weird nature of black holes, I normally respond with answers based on standard black hole theory, but I sometimes feel I should also call attention to the point that some people now think that the "black hole" solutions to the...

So I was calculating the temperature for a extremal Kerr black hole. G2*M2 = a2, where a = J/m. Using T = kappa / 2 /Pi... I'm assuming this is the correct approach. But my question is... The surface gravity of an extremal Kerr black hole appears to be zero, leading to a zero temperature...