Black holes Definition and 1000 Threads

Can anyone explain to me what exactly is a charged black hole?Where is the charge?Is it on the singularity or somewhere else?

Good day! The famous American scientist Kip Stephen Thorne once wrote a novel the name of which probably is like this: “The travel inside the Black Holes”. I wrote probably because I have not read it in English language, I read its translation in one of European languages. This is little story...

First of all, I know that that very large stars tend to form black holes, and smaller stars, but still massive in comparison to our sun, tend to form neutron stars. My question is, if matter is lost when a star collapses into a black hole, but can still form one, why is it that it is a star...

Well I'm a senior in high school have an independent study to finish for my physics class. I have started my research, however I am still needing to know how I am going to pull a good 10 pages of information from this project (which is how many the teacher is asking for). I just need to know...

The black hole is surrounded by an event horizon. No matter which fell under the horizon will never escape, even in the form of information (in the classical theory of relativity). So why is the star orbiting a black hole moving at the correct speed and trajectory, as if they knew the mass of a...

My question here is to ask what would be the consequences to theoretical physics if, it was discovered, that black holes do not exist in nature. For example, as gravity and pressure increases beyond neutron star, new, previously unknown quantum principles, similar in spirit to loop quantum...

Can there be planets revolving around black holes? I'm not asking about black holes at the center of galaxies, but other black holes.

I'm going to have trouble stating this question exactly in the language of GR, but I'm going to try my best. We have a manifold with two identical black holes falling into each other from a large distance with no angular momentum, both spin and around their collective center of mass. A ray of...

What would happen if two super-massive black holes collided with each other? I know it may be a very unlikely scenario. I just started thinking about this for about a week and I wanted to see what anyone had to say about it. Thanks!

A little philosophical question. What would you say is the purpose of a black hole? To create another universe? To somehow balance the distribution of mass? Any guesses or hunches? Just curious.

Hello everyone this is my first post. I just recently started getting interested in physics but just from a very theoritical view and in very simple ways My problem goes like this: As far as i am concerned according to Relativity Theory nothing can go faster than light. So then we have the...

hi, i was just wanting to get a few opinions on where and maybe even when a black hole goes to. It's something I've read into a lot in the past few months; and I'm really interested to find out what others think. Thanks

Imagine that you are an astronaut standing very far from a black hole.Now you throw a luminous body (a bulb may be) directly towards it.Now as it gets nearer the black hole,the light from the bulb as you observe it becomes more red-shifted.Eventually from your frame(consider it is an inertial...

I know that this can not be true because if it was, the universe would be mainly black hole by now but I can't seem to fathom how if something has an increase in mass (law of conservation of mass) from an external object, it does not increase in size. My next thought would be, if gravity is...

After the Big Bang it was a short period of inflation. After that the physics that we know is supposed to apply. After inflation the speed of the expansion was smaller than the speed of light and all the mass of the universe was in a relatively small volume. Why was not the universe a black...

Black holes-- time travel? Is it plausible for something to time travel by means of a black hole, or is that entirely science fiction?

Hi, I'm not a physicist so the answer to this question may be elementary but I can't figure it out for myself. I posted this elsewhere before finding this particular part of the forum. Black holes are famous because (almost) nothing can escape from them. Once an observer has crossed the event...

Hi, I'm not a physicist so the answer to this question may be elementary but I can't figure it out for myself: Black holes are famous because (almost) nothing can escape from them. Once an observer has crossed the event horizon, no more contact may be made with him or her. Thus it will...

Hey guys. If the string theory is correct (and strings are fundamental and the last building block) I had a thought that if and when a star collapses (due to whatever reason) it can reach neutron star status. Add more mass and it can collapse to a quark star. Now say that we add more mass and...

From watching "The Universe" on the History Channel, I have heard that there is a theory suggesting that on the "other side" of black holes may lie white holes that spew everything back out into another universe. I'm not sure how great of a source that show is, but that's not the issue here...

How we can prove the existence of black holes? And how they are located in in the space as they can absorb light too?

I am trying to reconcile three things: (1) The entropy of a black hole is proportional to the logarithm of the number of possible states of that object to give the same event horizon. (2) The only parameter for a S. black hole is its mass, since its electric charge and angular momentum are...

Is it possible for a cloud of gass to condense around a black hole and for fusion to start? Or another way to ask. Is it possible for a star to have a black hole at it's center?

I am sure this must have been asked before but here goes. If two black holes were on a collision course with each other or would pass close to each other. Would the smaller one get pulled into the bigger one?

Ok, starting with a 'test' universe with only two objects, a single particle and a neutron star just under the mass required to collapse further into a black hole. If the particle was set in motion near the speed of light, in it's reference frame the neutron star would gain (significant)...

seen a programe about super black holes in which some stars where orbiting them . speeding up as they are slingshoted around them or whatever the proper term for this is . so why if the black hole is strong enough to pull them in the first place why do they not get pulled in completely ... what...

hello, in Penrose diagrams it says that once you have crossed a first Cauchy horizon(of a rotating black hole) , then, with the repulsive singularity, it is possible to cross another Cauchy horizon, and then another event horizon to escape the black hole and go into another universe. so I...

Hello Forum, This is my first post :) Einstein's special relativity finds that length is contracted if the observer is moving at high speeds. Now, assume there is a mass at rest in space that is below critical density of a black hole. If an observer were traveling at high speeds past this...

I am very intrigued with the suggestion that what we understand of as our universe, may actually be inside of a black hole. also that black holes may contain universes Can anybody suggest any good reading on the above as I would like to understand things better. Thanks Keith

First post. Please be gentle. I`m not a scientist, i`m actually a 3D Artist. I just have a lot of faith in science unfortunately didn`t have the attention span to pay attention enough in high school and even more tragic is that my university didn`t offer any science courses! I was hoping it...

Hello fellow Cosmology fans and professionals! Does Dark Matter form into Black Holes, and do regular Black Holes attract and trap Dark Matter? Thanks!

If a black hole can "evaporate" via Hawking radiation then there is a radial flux of energy from the black hole? Put a box around on such evaporating black hole. When the black hole is gone there is less space in the box? If so is that space carried away by the Hawking particles? Thanks for...

Hundreds of "Rogue" Black Holes May Roam Milky Way http://news.nationalgeographic.com/news/2008/01/080110-black-holes.html Astronomers have long known about rogue black holes? How long? Is this a new revelation about DM and BHs?

Ok; I'm not a physicist... I'm not a mathematician... I'm not even in school, I'm just a computer guy who watches the Science channel a lot :) So don't yell at me... be gentle :) I've heard and read that the rate of expansion of the Universe may be increasing. Is it possible that it...

hello, I am new to this forum so I am not sure if this is the right spot for me to post my idea, but here it is. :smile: i was talking to a friend about differnt questions about how things work when he asked the fallowing question: "is it possible to creat a bubble where time completely...

According to everything I've read and heard (as a non-scientist), nothing can come out of a black hole. However, on a couple of documentaries I've seen on the Nat Geo channel in the last week, the astronomers talk about quasars as being massive jets that come out of black holes, because the...

I read recently that the entropy of a black hole is proportional to the surface area of its event horizon. Being that surface area is a two dimensional measurement, only requiring length and breadth, what does that say about the structure of matter contained in the event horizon? I'm not sure...

Suppose I have to pick one review paper on the observational status of astrophysical black holes. It should: -be as up to date as possible -be available for free online (preferably on arxiv) -cover both supermassive and solar-mass black holes Does anyone have any suggestions? This one...

Hey guys I'm new here :D , i came across this read online Edit by Evo: Removed link to blog Please scroll down to a big post by xodiac21. Its very interesting, but I'm here wondering about the part where you jump into the black hole and ur friend watching if u really GET into the black hole, i...

this is buggin me. could some one please explain in lay terms what they believe happens when 2 black holes are close enough to be in an elyptical orbit around each other at speeds that would be approaching the speed of light pryor to the smaller one being absorbed into the larger they would...

Well since we will never see something go into a black hole, won't we see everything the black hole tries to swallow around it? So wouldn't it be possible to see a black hole since a bunch of things would be around the event horizon. Answers are appreciated.

Please correct this if a widely accepted answer exists; please forgive my layman's terminology; lastly, forgive me for posting this to two forums but my first attempt got no takers... The "infinite" (unaffected by the local gravity effects) observer A knows that a rocket ship carrying...

What do we know about black holes swallowing dark matter? Dark matter exhibits gravitational effects, right [lensing and keeping star orbital speeds about galactic centers rouighly independent of their distance from a galactic center]? So it seems black holes should consume both normal and dark...

Would it be possible for something to pass through 2 event horizons,falling into both black holes? also,if it can,what would happen if the objecct in question (lets say a proton) was at a point where the forces acting on it were equal in every direction? say being at the centre of these two...

Hey, I am a little confused with the nature of black holes. I am under the impression that time is infinitely slow at a black hole's existence. I am also under the impression that black holes are a point of singularity, but have a defined mass. Gravitational force is only caused by mass...

Alright, so I'm kinda new to posting here, sorry if I don't understand things fully at this time. As for questions, I have a few of them. Firstly, what is the force of gravity at the event horizon of a black hole. Since photons have no mass, what would be the force required to trap it...

hello, how is it possible to calculate the only GRAVITATIONNAL time dilation and length contraction factor in the Kerr metric and/or the Kerr-Newman metric, for an object falling but otherwise at rest, since there is frame dragging, and the metric contains dt^2 components but also dt.dphi...

Hi all, I have been thinking about black holes and the different sizes that they come in. With regular black holes and super massive and all of the in between black holes it begs a question. Can one infinity be bigger than the other? All black holes are said to have infinitely dense centers...

I have a question concerning upper dimensional black holes. Basically my question would be: what are 4d and 5d black holes? But being more precise about my question, I would like to ask about their properties. I guess there is an analogy between 3d black holes and the other ones, so is then...

hey people..! I need to ask that whether time travel is possible ?.If speed of light is achieved..however besides this i also think that if speed of light is achieved nothing could stay at that speed virtually...what do you people think..?? Secondly, i was thinking that how do we know that...