Holes Definition and 1000 Threads

If dark energy causes spacetime or things in the galaxy to expand (acceleratingly), then won't black holes die due to expansion past the Schwarzschild radius, rather than simple radiation evaporation? (When black hole die, I mean, we have the ability to look into the space because it is no...

How did you find PF?: duckduckGo search. My math is very weak and I don't like explanations done using math. I read books with very little math. I try to use reason based on what I've read. My understanding is time slows down in gravity and it will actually stop at the event horizon (see...

Could someone explain to be the reason why size of the hole or grating in the case of Faraday cage is what determines if the screen or grating is opaque or transparent? I'm pretty sure it has something to do with interference patterns in classical physics. Thank you all in advanced.

I want to ask if you can theoretically chill the particles of a black hole and if it is possible to achieve it what will happen

My hypothesis: A sequence with the gravitational waves detected, sent by modulating radio waves, could be received and used by other intelligent beings to find the corresponding sequence within their records and then compare it to calculate our spacetime position in relation to theirs. As...

My understanding from General Relativity is that if as distant observers we watch a probe or any test mass approach a black hole, time dilation goes to infinity as the probe gets closer to the event horizon. This would imply that we would never observe a black hole form, or the collision of two...

I am currently studying the Vaidya metrics and I am a bit confused regarding the term Misner Sharp mass, and I am referring to Blau notes and in them the description is very deep which I surely don't need but just an overview. TIA

The reason why I think it could happen is that spacetime is being curved really extremely in black holes and when you draw a chart of spacetime near and in black hole , you can see that time axis is being bend towards the center of black hole and that thing is happening from all sides of the...

Before explicitly stating the Kerr metric let us discuss a bit what to expect, comparing it to the easiest solution to (in-vacuum) Einstein's equations that I know: the Schwarzschild metric. I studied that the Schwarzschild metric is derived under the following assumptions: the metric must be...

Homework Statement:: Hi, It's been a while since I have reviewed my basic semiconductor physics and I have some doubts. In a P-Type doped semidoncutor material, I understand that Group III elements such as Boron are added to a Group IV element such as Silicon and thus the Boron atom has one...

Well, my question arises because when one hears about black and white holes in divulgation, usually one hears that they are two kinds of "objects", the first one is a region that can only absorb things, and nothing can escape from it. While the latter is a region that only emits things and...

Does Hawking radiation at the event horizon of a black hole result in the reduction of the mass of the black hole? Quantum mechanics requires the creation and destruction of particle-antiparticle pairs throughout space-time. When this effect occurs at the event horizon of a black hole...

Do black holes exist? I have largely only heard that mathematically physics rules break down inside of a black hole by its current definition and that nothing can escape it beyond a point. And Hawking radiation has already shown to escape it beyond an event horizon. And Stephen Hawking in 2014...

I just want to know if Black Holes would be quantumly coherent.

How does mass determine the bending of space from inside a black hole?REPLY

Hello, This is a question I've been pondering on my own for some time. I have no formal education in advanced physics, only at the introductory undergrad level. I read that immense pressure can create black holes by compressing matter. I've read Laurence Krauss explain you'd need to compress...

A Paradox of the black hole is that GR states the stationary observer experiences time dilation, while the inflating observer experiences no time dilation. By the time the infalling observer reaches the event horizon, an infinite amount of time passes for the other frame of reference. But...

The paper is reasonably old and was written as a phd thesis by (I believe) a man from china. It was basically the first paper on the subject and in it he effectively (from what I understand) dropped particles into a black hole, counting the information added, and saw that the black hole changed...

Hi everyone, been reading this site for a while, and this question has been stuck in my head for 3 days and i can't shake it, so i figured I'd step out of the shadows and ask. There are some follow up questions that came on the same train of thought too. Can light pass by a Black Hole and get...

This should maybe go in the Beyond The Standard Model forum but since it's a paper about quantum cosmology I'll put it here. Feel free to move it if it's too speculative but that's exactly my question. That is: if it is... Perusing "The Area of a Rough Black Hole" - -...

Three Lectures on Complexity and Black Holes - could be a good read for quarantine!

I am grateful for anyone for their time to answer this question. Some theories predict black holes will evaporate and eventually disappear. From my limited understanding, Hawking's theory predicts that quantum effects near the event horizon of a black hole are responsible for blackbody...

This is on page 2, and I guess it is the key to understanding what they mean by linearized perturbation to a BH in the abstract. What is meant by gravitational fields, what is delta(g_ab) and delta\Phi ? A perturbation to the metric, and the 'gravitational field', sure. And where are these...

Physically speaking, why the insides of the least massive black hole should be any different from the heaviest possible neutron star?

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So Alice and Bob are hanging out near a really large black hole. It's quiet. Nothing has entered the BH is a while. Alice tosses Bob in and then waits long enough for him to collide with the singularity. Of course, Bob is keeping time differently than Alice - so I rather doubt that the time...

What will be mass flow rate of dry saturated steam through holes on a pipe. Pipe ID: 25mm, Steam Pressure 3 kg/cm^2, Holes' Dia: 3mm, Number of Holes: 5.

Here is a presentation on the discovery of two colliding neutron stars and the resulting phenomena such as gravity waves, gamma ray bursts, and synthesis of high atomic number elements. The author is a theoretical physicist who is involved in the research. He says that the neutron stars most...

Recently there have been a lot of studies of black holes colliding and the gravitational waves that they produce. My question is: What is the effect on the space between the two black holes before they collide. The stress must be extraordinary. That stress should be measurable by radiation...

Dark matter passes through everything, but is only influenced by gravity, so in the case of a neutron star, since dark matter doesn't interfere with ordinary matter, it can just pass through it, but neutrinos might be stopped by it's density, as neutrinos can just pass through stars almost as if...

How long would it take for an object, stationary with respect to a black hole (mass of the sun), to fall from 1 AU into it beyond its event horizon? From our frame of reference can we observe over time, a black hole growing in size as matter falls beyond the event horizon? From our frame of...

The thing is that this is an exercise that I have to show my teacher but I don´t know how to get the answer.The exercise says: "A body of mass m moving in the Keplerian field V = −M/r (in G = 1 units) has a total conserved energy, Etot = 1 /2( m r˙^2 + r ^2ϕ˙ ^2 )− mM/r. Show that the...

We have a project that relating with pipeline system and pressure control, the project is actually having goal to knowing how much pressure drop will occurs in pipe line system that in initial condition the pressure inside the pipeline staying at steady or constant in particular psi and at the...

The laws of physics breaks down at an atomic level, it also breaks down around black holes. could the two be related? could a black hole be an atom with a periodic number in the (insert ridiculous number here) ? If it were true that black holes where atoms / elements it'd turn two problems...

This is what I did: I know that ##v_1=\sqrt{2gh_1}## and ##v_2=\sqrt{2gh_2}## thanks to Bernoulli's principle. Using equations of parabolic motion I get ##h-h_1-\frac{1}{2}g(\frac{d}{v_1})^2=0## and ##h-h_1-\frac{1}{2}g(\frac{d}{v_2})^2=0##. This means I have two equations in two unknowns...

Can someone post links to the popularly accepted theories on black holes? Just about all of the information I come across is presented as scientific fact, regardless of how far-fetched some of these ideas may seem, or contradict each other

I have been curious if there is anything that would prevent a star that has the mass to supernova from going supernova at the end of its life. If that were possible could it then also be possible that black holes are not actually holes but something so massive that light and anything that comes...

Is it fair to say that all energy from a Gravitational Wave that enters the photon sphere of a Black Hole is destine to become part of that BH? And other parts that remain just outside of the photon sphere would experience gravitational lensing? Perhaps focusing the GW to an area of much...

Summary: Expansion of matter in the visible universe, total volume of space outside the visible universe, black hole mechanics, and general questions from an uneducated but extremely interested evolved monkey. Hello everyone! I do not know the rules of this forum, or any forum for that matter...

Hello everybody! I've notice that when using NPT fittings, the female fittings usually doesn't take all of the male threads: This has never bothered me since these are commercial fittings and the engineers who designed them know what they are doing. But now, I need to make NPT holes in a...

Last night PBS showed two shows on Black Holes. In the shows the host traveled on a supposed warp drive spaceship. A question occurred to me. Suppose for the argument that the Alcubierre drive were possible. Then suppose you were in a ship contained in a warp bubble moving through space at say...

Do black holes precess? I added some marks to a picture of quasar 3c175... can the highlighted distortion of the jet be interpreted as black hole precession?

I wonder why electromagnetic waves don't escape from a black hole while gravitational waves (obviously) do. What is the difference between the two kind of waves? And between gravitons and photons? thank you for your attention

So, for the end of this semester's introductory couse in General Relativity (undergrad) I have to do a project on "The analogy between the mechanical laws on a black hole and the laws of thermodynamics". I couldn't find much (at least on my own) about this particular topic in my university's...

Summary: I don't get it, why can we be sure, that black holes evaporate My simplified imagination about Hawking radiation is that when the vacuum fluctuation creates a matter-antimatter particles pair at the event horizon, thay are ripped appart by the tidal force and do not manage to split...

The first law of thermodynamics states that matter can only be transferred from one state to another, and cannot be truly destroyed. What happens to matter consumed by a black hole? What happens to it and where does it go? Does the first law still hold true?

Imagine two black holes at great distance. They are both spatially separate and both completely collapsed to a singularity. Gravity begins to pull them together. According to the equation for the gravitation potential energy of two objects at distance… Ug = -GMm/r …These two objects begin...

Summary: Thanks to CERN, we now have huge particle accelerators such as the LHC. We use them to enhance our understanding of quantum physics. As everyone know,particle accelerators are huge machines that smashes atoms into pieces at near the speed of light. I have heard making antimatter by...

I realize that my understanding of this matter and it's vast number of related concepts is rudimentary and incomplete. Kindly forgive my ignorance and try to explain your thoughts in layman's terms. Thank you for your time.

Trying to understand radiation near black holes, specifically sgr-a, and more generally "radiation in space" and its general threat to the survival of spaceship occupants. Please let me know if this would be more appropriate in a different section here, eg astrophysics. In my little story the...