All Questions
Tagged with event-horizon hawking-radiation
125 questions
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Would Hawking blackbody radiation theory still apply if there is no singularity in a black hole?
If it was shown that there was structure where a singularity should be, such as quarks and electrons, inside a black hole, would it still be expected to emit blackbody radiation as Stephen Hawking ...
user454585
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Are black holes …white holes? [closed]
Time dilation is infinite at the event horizon, after all.
As you approach the event horizon, your frame of reference slows asymptotically to match that of the black hole. While the universe around ...
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Black Hole Formation -- How Can an Event Horizon be Observed to Grow? [duplicate]
This is a question about black hole formation. To be clear, I’m not suggesting that black holes don’t form. It’s that I’m having trouble with the accepted explanation so there’s a flaw in my logic ...
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Do black holes evaporate prior to crossing their event horizon? [duplicate]
Bob falls into a black hole, watched by Alice who is far away.
Alice sees Bob asymptotically approach the event horizon while his clock asymptotically approaches 12:00 noon as his image redshifts (...
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Hawking-like radiation will probably be difficult to detect (even if it can be detected). Why is that?
I was having a conversation in another physics forum about horizons (like the event horizon of a black hole, or a cosmological horizon) emitting Hawking radiation and I mentioned that if the universe ...
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On entropy in a de Sitter horizon in a universe undergoing accelerated expansion?
I have a question about de Sitter cosmological horizons:
In this video by Leonard Susskind (https://youtu.be/n7eW-xPEvoQ?t=2324) he explains the concept of the Poincaré recurrence using particles and ...
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Don't all objects that collapse have an apparent event horizon and so Hawking radiates?
So say there is an object that is in the form of gas and dust and a core that weighs 10 earths is in the center and there is a sphere of gas around it that weighs 50 Earths, so the final mass is only ...
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About the geometric optics approximation in Hawking radiation
I have read Hawking's famous paper Particle creation by Black Holes (Ref. 1) and I have some doubts about the geometric optics approximation and its implications in the argument being made. The ...
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Does Hawking radiation depend of what's inside a black hole?
Or is it entirely based on the existence of an event horizon?
Does the fact that black holes radiate depend on any properties of its interior?
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Cosmological horizon and Hawking/Unruh radiation? [closed]
I have two questions about cosmological horizons and their emission of radiation
The first one is:
There are some authors that propose that dark energy or the accelerated expansion of the universe ...
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Why negative energy particles not created near a black hole? [duplicate]
If you take empty space right next to a black hole once in awhile, you will get a positive particle being admitted in the opposite direction of the black hole. In the creation of the photon this ...
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Can an entity trapped past the event horizon detect getting turned into Hawking radiation?
Assuming your space ship survives engaging with the accretion disk and any spaghettification issues:
(1) I’ve read that the crew can’t tell if they’ve already crossed the event horizon. There wouldn’t ...
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What would Hawking radiation look like from inside the event horizon?
Let’s say you fell into a rotating black hole, the inner horizon of the black hole is an infinite blue shift surface, so you should be able to observe events from the arbitrarily far future before ...
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How exactly does Hawking radiation occur? [duplicate]
I understand some parts of the theory, I've read from here https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Supplemental_Modules_(Astronomy_and_Cosmology)/Cosmology/Carlip/...
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Can someone help me understand backreaction?
I was reading a paper on black-hole information loss and it mentioned backreaction. I had never heard the word before so I googled it and was surprised to find no cohesive definition that I could ...
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Does the interior volume of a black hole grow forever?
Recently, I was reading about a article which tells about something known as "Susskind Complexity". The article states that the interior volume of a black hole grows forever.
How/why does ...
user355398
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Was Stephen Hawking's explanation of Hawking Radiation in "A Brief History of Time" not entirely accurate?
I've been looking into black holes and Hawking radiation recently (just on the surface level) and was reading "A Brief History in Time" by Stephen Hawking to understand the basics of ...
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Is there a classical description of Hawking Radiation?
Before quantum theory we knew accelerating electrons radiated electric fields. This is modelled classically (even though we know it is a quantum process emitting photons)
Similarly is there a possible ...
user84158
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What is the power emitted by a black hole for an observer located near its horizon?
The power emitted by a Schwarzschild black hole via Bekenstein-Hawking radiation is usually given for an observer at spatial infinity.
What is the emitted power for an observer hovering just above its ...
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What exactly makes a black hole STAY a black hole?
I don't understand how, as a black hole gets smaller and smaller from the excretion of Hawking radiation, it retains its ability to capture photons. I imagine there would be a point in its life cycle ...
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Are black hole event horizons hotter than our Sun?
The outside (not inside) of black holes, the event horizon, are apparently extremely hot, and get even hotter the smaller in size and mass they are. Being completely black, are they generally more ...
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Might the tiny Hawking radiation from our cosmic event horizon (CEH) be additive, since my CEH is not your CEH?
Concerning our cosmic event horizon, an interesting question arises from the seemingly innocent statement, "My cosmic event horizon is not your cosmic event horizon." Ie: Since 'you' and 'I'...
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Do the null geodesics of photons emitted by Hawking radiation arise from the event horizon?
It is a well-known explanation of Hawking radiation that it originates from the quantum fluctuations near the horizon. Does it mean that one can look at the photons (part of the radiation) and follow ...
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Given the time dilation at the event horizon plus black hole evaporation, can anything really ever enter a black hole? [duplicate]
There are many thought experiments about what it would be like to fall into a black hole, spaghettififaction, the singularity at the center and so on. But to me it seems that no object could actually ...
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Hawking radiation: how can gravity rip a pair of virtual particles apart without creating another pair of virtual particles in the process?
To the best of my (limited) knowledge of theoretical physics you cannot rip a pair of virtual particles apart without investing enough energy to create another pair of virtual particles...
If Hawking ...
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In Hawking's original Hawking radiation paper, how can we understand where the radiation comes from in the collapsing star spacetime?
In the original Hawking's paper "Particle creation by black holes" he first studies the collapsing star spacetime, and then the quasi-stationary phase of the black hole.
In the collapsing ...
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What's the current theory on final stages of black hole decay? [duplicate]
Okay, firstly, I know this question was asked here 11 years ago. And I know the correct answer is that we don't know because we haven't run the experiments and don't have a solid theory of quantum ...
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Why can't the information inside a black hole be reconstructed from what's left outside?
In trying to understand the significance of the black hole information paradox: regardless of what happens to information inside a black hole; how come it cannot, in principle, be reconstructed by ...
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Can the energy of a black hole's quantum field escape its event horizon?
From what I've read, Hawking radiation is produced far outside the event horizon. The radiation is produced by the quantum field of the black hole outside the event horizon. As more of these ...
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Does wavefunction collapses near event horizon? [closed]
Picture an electron falling into an event horizon, so far from what I read gravity is either not a force or it is extremely weak therefore it doesn't cause wavefunction to collapse unless the strength ...
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Does Hawking radiation from micro black hole get redshift like it stellar counterpart?
In a stellar black hole the hawking radiation gets redshift as it escapes the event horizon, would the same phenomenon occurs with a micro black hole? If so what is the threshold for the redshifting ...
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Is there an explanation for why Hawking radiation causes a black hole to shrink *without* referring to particle/anti-particle pairs?
An observer far from a black hole sees thermal radiation at the Hawking temperature. As a consequence, we are told that the black hole loses energy over time: that is, it evaporates. This logical step ...
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Smooth Event Horizon and backreaction
If an observer falls into a black hole then gradually he will encounter higher and higher energy Hawking radiation. Assuming that Hawking radiation is created just outside the horizon (say at $r=2M+ \...
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Can an observer have zero time component of 4-velocity?
I’ve been working through Schutz’s First Course in GR. In chapter 11 (second edition page 324), he does a rough calculation relating to Hawking radiation. To calculate the energy relative to an ...
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Question about the blackhole event horizon [duplicate]
If the surface area of a blackholes event horizon cannot decrease, how can hawking radiation work with out making the blackhole and its subsequent event horizon smaller?
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Firewall in Rindler horizon
In arXiv:1409.1231 in section 3.5 above equation (3.34) Daniel Harlow says
More precisely if the left and right wedges are completely uncorrelated, as in
the state 3.33, then the typical difference ...
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Can black holes evaporate into Neutron stars? [duplicate]
If adding mass to a neutron star eventually makes it a black hole, why do black holes after losing mass through hawking radiation not evaporate into Neutron stars?
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Would touching a black hole of a small mass (the mass of an apple) cause you to spiral in and get dead?
I know that a typical stellar black hole would spaghettify someone who crosses its event horizon.
Is this also true for a hypothetical tiny black hole with a small mass (the mass of an apple)? Would ...
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A Doubt on Hawking Radiation: What Birrell wants to say here?
Well, I know basic General Relativity but I still learning the basics of Quantum Field Theory (therefore without mentions on curved spacetimes). But, I'm trying once and a while to become more used to ...
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Falling into an evaporating black hole
If
It takes an infinite amount of coordinate time to fall into the horizon of a black hole
It takes a finite amount of coordinate time for a black hole to evaporate due to Hawking radiation
All ...
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Why black holes lose energy? [duplicate]
It is often said that black holes lose energy throughout the process called Hawking radiation. My question is, since the process of creating particles is random, why do the black holes captures more ...
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Can two photons with correlated polarizations pass into a black hole and be emitted as Hawking Radiation with the correlation intact?
In this scenario photons would be emitted before they reach the centre of the black hole and before colliding with matter from a collapsed star.
user291095
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Any effects from touching Event Horizon?
We have a metal rod travelling through vacuum space towards a cosmic Schwarzschild Black Hole.
The proportions of the black hole and the metal rod are such that the metal rod is twice the ...
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Could this mean Hawking Radiation is wrong?
Does a virtual particle that enters a black hole also become a real particle just like the one that escaped? If so then the mass taken away from the black hole by the escaping virtual particle would ...
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Do Event Horizons Always Expand?
I am reading Kip Thorne's book Black Holes and Time Warps. In a section dedicated to Penrose, he discusses that Penrose and Hawking together postulated that the horizon of a black hole must always ...
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Why doesn't a Planck type derivation work for Hawking radiation?
In Planck's derivation of black body radiation, Planck hypothesized $E=h\nu$ and got the correct black body radiation spectral function.
What is confusing me is why don't similar arguments work for ...
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Do cosmological event horizon evaporates like black-hole horizon?
While the inflation phase of the universe, expansion was exponential and so the universe was de Sitter-like. So, for a point-like observer, there was a cosmological event horizon. Do this horizon ...
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Who wins the race between an astronaut falling towards a black hole and the event horizon shrinking due to Hawking radiation? [duplicate]
From an external point of view, an astronaut falling towards a black hole takes an infinite amount of time to reach the horizon, while the horizon vanishes in finite time due to Hawking radiation. ...
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Can a particle just below the event horizon of a tiny, fast shrinking black hole make a comeback?
A particle has just entered a minuscule (and non-rotating) black hole which is at the end of its life. The black hole is getting smaller really fast as it boils away ejecting tonnes of Hawking ...
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Direction of Unruh radiation
In case of a black hole, the direction of the Hawking radiation is from the horizon to the observer. The corresponding effect in the Rindler spacetime is the Unruh radiation.
Intuitively, a rapidly ...
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