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CPT and Event Horizon

Is the example of neutrino entering the event horizon of BH quoted from this article a valid possible example of CPT violation due to the presence of event horizon in BH ? Please, note that there is ...
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2answers
143 views

Dipping a Dyson Ring below the event horizon

The basic assumption about inescapability beyond the Event Horizon is that the necessary escape speed (orbital speed) would exceed speed of light, therefore no object can achieve it. Now, would it be ...
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2answers
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Do all event horizons emit radiation?

So, the event horizon around a black hole emits radiation, and Rindler space is full of thermal energy. I guess I have two questions- does the Unruh effect have anything to do with radiation from the ...
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3answers
179 views

Why are black holes special?

A black hole is where it's mass is great enough that light can't escape at a radius above the surface of the mass? I've been told that strange things happen inside the event horizon such as ...
2
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1answer
92 views

What happens when a black hole dies?

It just vanishes into space leaving nothing behind or does it expel some material? Also, talking more about black holes, as far as i understand the term "temperature", it is defined by the amount of ...
2
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1answer
68 views

If charged particles always attach to black hole event horizons, how can ordinary matter fall in?

(A friend at work kindly loaned me loaned me his copy of Kip S Thorne's "Black Holes & Time Warps". This may have been ill-advised... :) BH&TW 1994 paperback p.410 Figure 11.5: ... all ...
2
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1answer
118 views

Cosmic event horizon

I had a question regarding cosmic event horizon. Let's say that a far away solar system has just crossed the cosmic event horizon due to the expansion of the universe. In that solar system let us ...
2
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1answer
65 views

Can light be launched outwards from an event horizon? [duplicate]

There's something which I don't quite get about black holes and event horizons (feel free to tell me if I got something completely backwards at any step along the way): Say we have a singularity and ...
2
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1answer
178 views

Would dense matter around a black hole event horizon eventually form a secondary black hole? [duplicate]

Possible Duplicate: Black hole formation as seen by a distant observer Given that matter can never cross the event horizon of a black hole (from an external observer point of view), if a ...
2
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2answers
184 views

event horizons are untraversable by observers far from the collapse?

Consider this a followup question of this one In the classical schwarszchild solution with an eternal black hole, the user falls through the event horizon in finite local time, but this event does ...
2
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1answer
85 views

Where is the basketball event horizon?

I'm watching a lot of basketball this month. A common event is the ball going part way into the hoop and then coming out again. Announcers sometimes claim that the ball was "halfway through" when it ...
2
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2answers
77 views

Do black holes exert an infinite amount of energy at the event horizon?

An interesting thought crossed my mind when reading about Hawkings' apparent horizon theory. If we assume that event horizons do actually exist, it would seem that black holes violate basic laws of ...
2
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1answer
73 views

Physical meaning of the Rindler hyperbola vertex and the Rindler lines

Two questions regarding the Rindler diagram: 1) Does the vertex of a given hyperbola in the diagram have physical meaning? I know it is the inverse of the constant proper acceleration ($\alpha$) ...
2
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1answer
105 views

Event horizons in Newtonian mechanics and Galilean relativity

I've been revisiting classical physics (in the sense of Newtonian mechanics and Galilean relativity) and I was thinking why can't we have an event horizon in classical physics? Is it because the ...
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0answers
87 views

Gravitational waves as information carriers

Is it possible to utilize gravitational waves as a delivery system for information between two observers straddling the event horizon of a black hole? And why ?
2
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1answer
60 views

How is black hole affected by gravity of nearby bodies?

I run into wikipedia articles about ergosphere of rotating black holes. What if some massive body passes nearby some black hole: is something like ergosphere produced, or is the event horizon ...
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1answer
154 views

How much extra distance to an event horizon?

How much extra distance would I have to travel through space to get from Earth to a stellar mass event horizon? (compared to the same point in space without a black hole)
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6answers
207 views

Is black hole bright at center?

As we know that light photon cannot escape the gravity of black hole so I was thinking that if that is the surface of the black hole would be bright as all the photons would be there only. Am I right ...
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3answers
234 views

What actually happens to a light ray on a Schwarzschild black hole horizon?

I know the Schwarzschild event horizon is a null surface generated by null geodesics. But what does that actually mean in terms of the path of a light ray that reaches it? Does that mean the geodesic ...
1
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1answer
64 views

How does negative energy from Hawking Radiation cause a Black Hole to shrink? [duplicate]

Hello this is expanding upon a question that was previously asked on stack exchange that I linked below. From what I understand of Black Holes is that overtime Hawking Radiation results in the Black ...
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1answer
119 views

How can a black hole have spin?

How is it possible, or even meaningful, to say that a black hole has spin? (Tangentially, if the singularity is assumed to be a point, it must have either zero or infinite angular momentum, in both ...
1
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1answer
105 views

Why can't we see things swallowed by black holes?

Apologies in advance, I'm a layman with only a school-level education in physics. If an object approaching the event horizon of a black hole has its light cone progressively bent towards the black ...
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1answer
105 views

Visual representations of black holes

Some black holes emit jets that are rapidly circling the poles of what appears to be a sphere at the center of the black hole, cf. Fig. 1. Is there really a sphere here and how far (relative to the ...
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1answer
62 views

Can we build a synthetic event horizon?

If we imagine ourselves to be a civilization capable of manipulating very heavy masses in arbitrary spatial and momentum configurations (because we have access to large amounts of motive force, for ...
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0answers
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Black hole entangled with the cosmological horizon

Maldacena and Susskind recently proposed a interesting and very suggestive duality between entanglement and topological identification: http://arxiv.org/abs/1306.0533 But are such ideas applicable to ...
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0answers
28 views

Graviton through the horizon and force felt outside a black hole [duplicate]

Gravitational force is mediated by graviton exchange. If I am standing outside a black hole, I can of course feel the attracting force towards the black hole. This should correspond to gravitons ...
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0answers
194 views

How can things at the event horizon slow down and appear to stop to a remote observer?

So they say the remote observer will never see anything fallen to the black hole, because any object will slow down as it gets closer to the event horizon and eventually stop to stay there forever. Am ...
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2answers
178 views

Second law of thermodynamics implies a linear cosmology?

If one applies the second law of thermodynamics to the Universe[1] as a whole then one might expect that the entropy of the Universe always increases as time goes forward (or more accurately that the ...
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1answer
115 views

Can you enter a timelike hypersurface?

As I understand it, a timelike hypersurface is one that has only spacelike normal vectors. But does this not imply that a the geodesic of a particle crossing it must be spacelike at that point? But ...
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1answer
49 views

Can Event Horizon be created without actively involving Gravity (Spacetime curvature)?

The definition of Event Horizon I took from Wikipedia: An Event Horizon is a boundary in spacetime beyond which events cannot affect an outside observer. From the definition, I can abstractly ...
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2answers
100 views

Causal reconnection

Can causally disconnected regions join up again? For example the universe is expanding faster than light creating cosmological horizon, but what if something causes the expansion to slow down and ...
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2answers
157 views

If NASA could send a camera into a black hole, could we then see what's inside the black hole?

Inspired by Stephen Hawking I recently tripped upon an idea of what is really inside a black hole. I thought if NASA (or any other space agency) could send a super protected camera into a black hole, ...
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2answers
36 views

Are the cosmic horizons observer-specific?

It is known that all observers will agree on the position of the black hole event horizon. But what about the cosmic horizon of the de Sitter space? Can one say that the horizon of scientist1 is ...
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2answers
89 views

Photons hitting the Black Hole Singularity

I was watching one of Dr. Susskind's Lectures on String theory and he was talking about black hole singularities (see the 40 minute mark of this lecture ...
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0answers
67 views

Do black holes exist? [duplicate]

Do black holes exist from our point of reference? From our point of reference nothing actually goes inside the event horizon right? So is there anything inside the event horizon from our reference? If ...
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0answers
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Is the Casimir effect also present between two event horizons?

A follow-up to this question: Is the Casimir effect also present between two event horizons?
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0answers
60 views

Is the black hole surface area actually zero?

From quantum mechanics we know that entropy of a part can be smaller than the entropy of the whole. I wonder whether a similar rule works for GR as well. Quantum mechanics predicts that the entropy ...
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1answer
69 views

Boundaries of Black Hole and Observable Universe

Are the boundaries of a black hole, the event horizon, similar to the boundary at the end of our observable universe?
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0answers
33 views

How much extra distance to a CERN event horizon? [duplicate]

How much extra distance would a scientist have to travel to get to the event horizon of a mini black hole if they ever make one?
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0answers
41 views

Can a black hole actually grow, from the point of view of a distant observer? [duplicate]

Possible Duplicate: Black hole formation as seen by a distant observer I've read in several places that from the PoV of a distant observer it will take an infinite amount of time for new ...
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1answer
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Something about things going in black hole?

Don't hit me if the question is too lame but here it goes 1) We all know that to see something light must get reflected from it's surface and then reach our eye's 2) Any thing which goes in black ...
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2answers
32 views

Can the Escape Velocity of Regions inside the Event Horizon of a BH be calculated through Newtonian Physics?

Do Newtonian Physics help in determining the escape velocity at and inside the event horizon at a distance less than Schwarzchild Radius from the singularity?
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1answer
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Fine structure parameter $\alpha$ at event horizon

As magnetic field lines collect at a black hole event horizont (for no field lines will be present in the black hole) then ratio of electric field to magnetic field will change, so by this change in ...
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1answer
35 views

How to calculate the gravity level at the boundaries of a black hole? [on hold]

Imagine that a body is attracted to a black hole and it has a mass $M$, if the body is moving with $v=.99c$, will its speed and mass affect the gravity relation between the body and the black hole? or ...
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1answer
155 views

Way to escape from a black hole

I’ve had a question on WHY a traveler couldn’t “escape” from a black hole under specific conditions (I have an image I'd like to send to clarify, but the website won't let me)> The key is for the ...