All Questions
15
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Time required to reach Black Hole's Event Horizon from outsider perspective?
Let's imagine a pair of particles that is entangled. One (call it $P_1$) is released and then falls to a black hole from a distant $x_0$, (for example $x_0=5r_s$) and velocity $v_0(=1/2c)$, while the ...
2
votes
1
answer
149
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How can the infalling observer see the event horizon to retreat in front after the observer crossed it (and can't even notice it)?
I have read this question:
so looking toward the singularity, you see the horizon retreating from you as you fall in - even after you've already crossed the horizon.
Are black holes naked ...
- 29k
0
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0
answers
36
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If frequency shift is positive then how to interpret it?
Let say lightning is happening at $r=r_{A}$ from center of gravity and our observer at $r=r_{B}$ with $r_{A}>r_{B}$ then if we get frequency shift is positive (by considering let say schwarzschild ...
0
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0
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63
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Does someone falling into a black hole see the future falling objects? [duplicate]
For someone falling into a black hole space and time swaps signs - the time coordinate of an outside observer becomes his space coordinate. That means, for any plane parallel to the horizon and inside ...
- 1,161
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1
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51
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"Different reality" inside a black hole
why does our perception of space and time entirely change inside a black hole? And why does time not stop inside it from the perspective of the inside observer, however, extremely slows down for the ...
- 27
1
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1
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138
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What does an external observer see if you shine a laser pointer while crossing an event horizon?
If I understand correctly, the event horizon of a black hole is the boundary beyond which we cannot perceive or describe any events, and all objects appear to freeze when falling in until their light ...
- 21
9
votes
4
answers
2k
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Is time sped up when orbiting a black hole? Why? What does that mean?
I was watching a very interesting short documentary in which the author said that while it takes 8 minutes in space to loop around the black hole, an observer from Earth observes that it takes 16 ...
1
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0
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56
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Thoughts on Black Holes [duplicate]
Given that time slows to a stand-still at the event horizon of a Black Hole, how long would it take a black hole to form, from the perspective of an outside observer?
It would seem, as a massive star ...
- 25
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1
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115
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What (if any) significance exists in the analogy between the speed of light limit and the Schwartzchild radius of a black hole
I have always been intrigued by what seems to be very similar characteristic of the phenomena of traveling very, very fast, (close to the speed of light , and the Schwartzchild radius.
AS a body gets ...
- 190
3
votes
5
answers
3k
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Time paradox inside a black hole
At the event horizon of a black hole, time and the spatial direction toward the center exchange places. The direction inside the black hole from the event horizon to the the singularity in the center ...
- 12.7k
4
votes
2
answers
271
views
Planets close to a black hole
Like in the movie Interstellar, when they go near "gargantua" the big black hole that have a planet orbiting the black hole, they go on the planet and every minute equals X years in earth time. If ...
- 41
0
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1
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243
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For a distant observer can a black hole form and grow in finite time? [duplicate]
Consider an observer at a significant distance away from a collapsing star.
As such when a singularity is born at the core of the star the observer would never see it grow anymore than the ...
- 838
0
votes
1
answer
686
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Does infalling matter ever cross the event horizon? [duplicate]
Assume you are immortal, then say if you fell towards a blackhole,
to an observer far away you will appear to slow down as you approach event horizon and gradually come to stand still.
However for ...
- 838
2
votes
1
answer
275
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Can you shine a laser on an object that has fallen into a black hole? [duplicate]
I've been having a small back and forth on another website about the nature of objects that fall into black holes.
I know that they never reach the event horizon from the perspective of a distant ...
- 31
163
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9
answers
40k
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Does someone falling into a black hole see the end of the universe?
This question was prompted by Can matter really fall through an event horizon?. Notoriously, if you calculate the Schwarzschild coordinate time for anything, matter or light, to reach the event ...
- 358k