Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [black-hole]

Questions regarding points of extremely high mass density, which creates an extremely strong gravitational field from which light cannot escape.

0
votes
0answers
24 views

How long a photon stay suspended in orbit around a black hole?

Can a black hole free from an accretion disk collect photons in the photon sphere in a prolonged stable orbit? Could enough photons be in orbit to shade the actual black hole with light? Would a ...
25
votes
3answers
4k views

Why can't light escape from a black hole?

I've heard that light can't escape from a black hole. Can it? If not, why?
2
votes
0answers
114 views
+50

How does the size of a naked black hole effect its photon sphere?

What effect does the size of a black hole have on the size or density photon sphere and proximity to the horizon? If a person is in space looking at 2 black holes (one of them big and the other ...
10
votes
2answers
360 views

Why black holes have positive energy?

How could Hawking get the conclusion "[...] and black holes have positive energy. That’s why empty space is stable. Bodies such as stars or black holes cannot just appear out of nothing. But a whole ...
2
votes
1answer
98 views

Is this a black hole?

While researching about galaxies in Google sky, I came upon a strange area. Co-ordinates: 11h 6m 15.0 seconds | -77° 22' 9.8" A lot of space around this body is empty, is there a possibility that ...
32
votes
7answers
4k views

Does matter accumulate just outside the event horizon of a black hole?

My understanding is that time slows and approaches stopping when approaching the event horizon of a black hole. I have seen this explained several places, including a brief explanation in the last ...
4
votes
1answer
72 views

Is an elliptical orbit around a black hole, or an orbit consisting of three bodies (including the black hole) possible?

If this is possible, would it then lead to an object undergoing varying time dilation (predictable variation with elliptical and random variation with three body)?
2
votes
1answer
105 views

Shouldn't we not be able to see some black holes?

Whenever there is a picture of a black hole, (even though they are artist depictions, this is how they are described) most are shown kind of in a flat disk like this. My question is, why do we see ...
2
votes
1answer
70 views

Time Dilation and Particle Decay

I am teaching myself astronomy and I'm working on a basic problem regarding time dilation around black holes. The question is basically this: if a neutron were ejected from a nucleus at a distance of ...
15
votes
3answers
1k views

Infalling observer could never cross Black Hole event horizon? [duplicate]

I have an interest in cosmology, but I would no way consider myself an expert. It would be great if the more knowledgeable contributors would be able to answer the question I have posed. The intense ...
2
votes
1answer
136 views

Do falling bodies ever slow down?

I've had some discussions recently about black holes, and the issue of infalling bodies taking forever to reach the event horizon. That's essentially what Einstein said in his 1939 paper on a ...
9
votes
3answers
14k views

Life planets orbiting black-holes. Can/Do they really exist?

So, I watched Interstellar and if you watched it too you know that there's a planet orbiting a black-hole, they call it Miller's Planet. According to the movie, every hour on Miller's Planet is ...
16
votes
3answers
3k views

What is a singularity? What is at the center of a black hole? Specifically regarding space-time

So because I can only really think of space-time in 2-dimensions like a sheet of something, my assumptions might be wrong to begin with. I was watching a YouTube video on black-holes and there was a ...
13
votes
2answers
935 views

Would a black hole evaporate via Hawking radiation before you fall past the event horizon?

It takes an infinite amount of time for something to fall past the event horizon of a black hole from the perspective of someone outside the event horizon. Black holes also evaporate after a finite ...
0
votes
1answer
104 views

Need help with a simple Blackhole question

Suppose the amount of mass in a black hole doubles. Does the event horizon change? If so, how much does it change?
8
votes
2answers
1k views

What's that ring that only now appears in black hole illustrations?

If you'll notice, space time starts to deform near the black hole, but then at considerable distance from the black hole' surface, images in the background become ultra-distorted, but then as you look ...
4
votes
3answers
434 views

Techniques for locating origin of gravitational waves

The gravity wave detections (GW150914 and GW151226) have both been ambiguous in their exact position, the LIGO papers (GW150914 and GW151226) give no precise information about the location of the ...
1
vote
2answers
255 views

Fate of helium moving toward a singularity

On the molecular level, if an atom, consider helium, were to fall into a black hole, what would be the ultimate fate of its electrons, protons and neutrons?
1
vote
3answers
234 views

Why doesn't the vertical light beam get out of a black hole?

I'm asking this question as a follow-up to if light has no mass why is it affected by gravity? Imagine you’re standing on a gedanken planet, shining a laser beam straight up into space. The light ...
6
votes
1answer
153 views

Spaghettification of hard-things/Elements

Is it possible for a black-hole to easily stretch or turn any hard object like (Diamond , Gold bar , Platinum bar , Brass) into spaghettification state in just a seconds or minute once it gets near ...
5
votes
2answers
161 views

Can a black hole undergo a Penrose process inside another black hole's ergosphere?

I recently watched this video on black holes: https://www.youtube.com/watch?v=ulCdoCfw-bY And that statement should give you an idea of my level of understanding :) I was wondering if a spinning ...
4
votes
4answers
2k views

Is a black hole a perfect sphere?

I know all about how black holes form and why their gravity is so strong. However, is the gravity equally powerful in all directions? Will the event horizon appear as a perfect sphere?
2
votes
1answer
52 views

preserve information in a black hole

How is information preserved on the surface of a black hole? Is there an compression algorithm for storing the information? What if there is a uniformaly complex object dropped to the black hole? ...
2
votes
0answers
45 views

How far away was the binary black hole that produced GW170729?

GW170729 was gravitational wave signal's detected by the Virgo and LIGO detectors. I read the following in a news report: Known as GW170729, in accordance with the date of its discovery (in US ...
1
vote
1answer
65 views

What is the exact meaning of vicinity of Black hole or a disk? the same as inside?

What is the exact meaning of vicinity of Blackhole or a disk? Is this the same as inside the horizon for black holes? If so, why people don't say inside of BH, simply. What is the difference? I use ...
0
votes
1answer
60 views

Is it possible for particles to be accelerated FTL inside BH travelling towards the singularity? [closed]

Maybe just maybe it is possible for a particle to travel FLT inside of black hole because of the singularity gravitational force This could be due to the fabric of space it self falling towards the ...
2
votes
1answer
39 views

Is the Bondi Radius the Same as the Schwarzschild radius?

$$2MG/c^2$$ This is the expression for both, but some authors use one name and it has confused me. Is there any distinction?
-2
votes
1answer
74 views

Can blackholes appear white and black? [closed]

Depending on the angle you view a black hole could it appear white, black or grey? Excluding how the gravitational lensing would make all the light emitted either red or blue shifted creating a ...
4
votes
1answer
76 views

Could a distant black hole (detected due to its mass) be in reality a Dyson sphere?

When the black hole is only detected due to its gravitational effects on other stars and their light, could it be possible that it is in reality a working Dyson sphere? It would still have at least ...
0
votes
1answer
132 views

What would a black hole merger look like?

Ship 1 is out side the black hole. Ship 2 is nearing a black hole. To ship 1 it would appear that ship 2 would be moving slower to the point it would seem like ship 2 stopped moving the closer to the ...
0
votes
0answers
47 views

How do black hole spinning at speed of light expose its singularity?

Black hole can spin very rapidly something about conserving momentum once a massive star used up its fuel and collapsed under it own weight, if black hole can spin at speed of light it could expose ...
0
votes
0answers
26 views

What can I learn from, or notice in the LIGO Orrery video?

The Ars Technica article Physicists detected gravitational waves from four new black-hole mergers notes that This brings the total number of events detected by LIGO and Virgo to 11. It also has a ...
1
vote
1answer
65 views

Can hawking radiation be eaten by another blackhole?

Just a theory, from this video. At last, only the black holes are gonna exist and even they'll decay because of hawkings radiation. As black holes emit hawkings radiation, then if one emits it, ...
5
votes
3answers
87 views

Does a gravitational wave loses energy over distance?

How does a gravitational wave travel over vast distances without losing its energy? Could they go on forever as long as the Space? Thank you
1
vote
1answer
56 views

How to convert factors of time dilation into something relatable? [duplicate]

On this post, Time according to the gravity of Sagittarius A? They found the factor of time on the varying distances from the SMBH, I am curious on how to turn those factors into relatable terms ...
0
votes
1answer
61 views

Black hole, escape velocity, going up?

I do know nothing can escape a black hole, and I understand popsci explanation of geodesics of space-time around and inside the event horizon. I however have some trouble with following thought ...
5
votes
3answers
517 views

Is there a possibility that a white dwarf can turn into a neutron star or a black hole?

I know that a white dwarf is mainly balanced by electron degeneracy pressure and that if it gains more than 1.4 solar masses from any source (such as a companion star or a collision), it explodes as a ...
3
votes
2answers
101 views

How does a blackhole burp?

Recently on the discovery channel I heard that a black hole burps matter out of it when it consumes more than it could process at a time. Given that even light cannot escape from a black hole, how ...
0
votes
0answers
22 views

How many fluorescent iron lines?

An iron atom has 26 electrons. Its 6.4 KeV line is a fluorescent line. There are 6.7 and 6.9 KeV lines also. How do they form? An electron from which energy level fills in which energy level? Is there ...
8
votes
2answers
3k views

Do all galaxies have a black hole in the center?

Would I be correct if I stated that all galaxies have a black hole in the center? Since other galaxies orbit around a center point in a galaxy - the barycenter, right? - I would assume at this point ...
8
votes
2answers
526 views

Are there upper or lower mass limits for black holes?

Natarajan & Treister (2008) describes a practical upper limit for black hole masses at $\sim 10^{10} M_\odot$. This is all due to the black hole's interactions with nearby matter. However, is ...
2
votes
1answer
142 views

Could Planet Nine be a tiny black hole or an exotic compact object such that it escaped detection? What would its bounds be?

Planet Nine (a variant of the old X-Planet and Tyche-Thelistos hypothesis) proposes a super-earth planet at the edges of the solar system with a mass of around ten Earths. However, given the interest ...
12
votes
4answers
2k views

Do black holes have energy?

So black holes are created by certain dying stars and when the star runs out of nuclear energy gravity wins out and the star implodes. An entire star’s mass collapses down into a smaller and smaller ...
6
votes
1answer
148 views

Could a black hole pass quiescently through the Oort cloud?

Imagine a stellar-mass black hole passing through the Oort cloud, perhaps a quarter to half a light-year from the Sun. How black would the black hole be? That is, any matter that fell into the black ...
-1
votes
2answers
69 views

Since gravity is like an indent on a piece of paper (the space/time matrix) to a marble, can the black hole eventually suck in the matrix?

Can a black hole suck in time? People claim that if you were to put a bowling ball on a trampoline and rolled much smaller balls through the deppression, some would stay in "orbit", some would roll ...
1
vote
1answer
96 views

What cosmic disaster is most likely to happen? [closed]

Of all the different ways that the Earth can be destroyed what ways is the most likely that could happen?
6
votes
4answers
5k views

Could Black holes forge heavier elements that have yet to be discovered?

Observations The heaviest elements known in abundance in nature are forged deep within stars. These elements are made possible by the high densities/pressures within the stars. Black holes are known ...
1
vote
1answer
52 views

Once a black hole is formed, is there anything other than Hawking radiation which shortens its life?

Hawking radiation is supposed to very slowly evaporate a black hole (terms and conditions apply :] ). Apart from Hawking radiation, is there any mechanism or effect that can make a black hole cease ...
-1
votes
1answer
112 views

How does the center of a black hole can contain so much mass? [duplicate]

We know that "In the center of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become ...
1
vote
2answers
68 views

Movement of the Sun in space

Does the Sun undergo any cycles or revolutions approximately every 24,000 years or 8.6 million years? In Hinduism it is believed that the Sun revolves in an elliptical orbit around a large mass at ...