Black holes Definition and 1000 Threads

Here is an oddball that I am wondering - could the spaghetification be countered by time dilation? Because as you approach a black hole (assuming you go in legs first) not only do your legs experience higher gravity than your torso, but they are also subjected to more time dilation - as they...

It heard it stated that light cannot escape from a black hole, yet light continues to propagate at the speed of light even in a black hole. Can someone explain to me how it can be that light can't escape yet does not slow down?

Hi Everyone, first post here, another enthusiastic amateur I'm afraid so please excuse my general ignorance! I struck me the other day that it should be possible to find an arrangement of large galaxies that would allow light emitting from our galaxy to be bent back towards us. This would give...

If they are so insanely dense and their gravity is so mind-numbingly great, what prevents a neutron star from immediately collapsing into a black hole?

I have some questions regarding things that boggle my mind about black holes. These things seem to me like paradoxes, and I was wondering if someone could explain them. 1. How do you measure the distance to a black hole? As far as I understand the distance to a black hole is defined as the...

My professor wants me to make a 15 minute oral presentation on black holes for an event we have going on on campus. How should I structure it? I think I have a pretty good understanding of the concept of a black hole, but I don't want to get caught off guard during the 5 minute Q&A section. My...

The Einstein-Cartan theory is, to my mind, a completely straightforward generalization of General Relativity, and indeed seems like a necessary generalization if we are to accommodate particles with intrinsic spin. (The mathematics for this claim is beyond me, but the layman's summary is this...

I'm very new to the understanding of Hawking Radiation. I don't know much about this theory, but I do know that Hawking radiation works on a Quantum scale. I know that with black holes this theory proposes th idea that over time black hole lose mass because of "Spontaneous appearing positive and...

According to Hawking [1] it is posited that light photons at the event horizon of a black hole must cease to move, and remain motionless for the entire lifetime of the black hole. It is also observed [http://dls.physics.ucdavis.edu/~scranton/LensedCMB/a2218.gif] (and calculated) that the path...

this paper Do Black Holes End up as Quark Stars ? R.K.Thakur (Submitted on 25 Feb 2007) The possibility of the existence of quark stars has been discussed by several authors since 1970. Recently, it has been pointed out that two putative neutron stars, RXJ 1856.5 - 3754 in Corona Australis...

Since light is entirely incapable of slowing down, what happens when light approaches a black hole such that it's trajectory passes through the exact center of the black hole? It seems, based on what I currently know, this would mean that the gravitational force pulling on the light would be in...

For black holes to "trap" light, the light would need to enter into some sort of orbit, but it seems like that might have some odd implications with relativity. If light is revolving around the center of a black hole, that would mean the light waves/photons would constantly be changing...

Hello people, I have a question regarding black holes. The way i understand it, black holes form in supernovas, and they occur because the gravitational pull of the stellar remnant is so great that nothing can stop it, and it basically collapses down to a singe point, virtually nothing... Now...

So i was watching this video : And it got me thinking... i began wondering why, when space contracts from someones frame of reference (In the video, this would be the frame of reference of the cat), why is it that the protons don't become black-holes when the space contracts? If the density...

Do the black holes have infinite mass? If no then how can they have infinite density? Can we suppose that all the universe is orbiting a black hole (as heaviest masses bend the space time most) and loosing energy at some rate ?

A book I read says that when virtual particle-antiparticle pairs are created near a black hole then sometimes one of the particle pairs will be captured by the black hole while the other one will be freed to move away as a real particle - then this causes the black hole to lose mass and thus...

Hi, what is the percentage of Galaxies where we expect a central black hole? What type are those Galaxies? Thanks!

Well, do they? Also: black holes, unlike elementary particles, have continuous distribution of rest mass, because they are free to absorb photons and gravitons of arbitrary mass, and kinetic energy of particles they capture. If two Kerr or Newman black holes have equal spin, which happens to be...

What particles that constitute the black holes?Does normal particles constitute the black holes? How can we calculate the ratio of types of particles in the universe(we consider known matter but not consider dark energy and dark matter)?How can we calculate the total number of particles in the...

Questions about black holes: Various articles mention that it takes infinite amount of time to observe something pass through the event horizon. Does this imply that the redshift observed from afar would carry on forever, that the infalling object would just become dimmer and dimmer, but never...

Hai pf, I had a doubt? we were well known about black holes still it act as a mysterious one. Well my question is about collision of two black holes. what happens if a highmass of black hole colloide with lowmass of black hole? Is the highmass black hole will suck the low mass black...

Black hole is considered an almost ideal black body by being a perfect black hole. But does it ideally absorb everything coming in the vicinity of its impact? Is it really possible for anybody to either ideally absorb or ideally radiate energy?

http://arxiv.org/abs/1507.05760 Higgs boson cosmology Ian G. Moss (Submitted on 21 Jul 2015) The discovery of the Standard Model Higgs boson opens up a range of speculative cosmological scenarios, from the formation of structure in the early universe immediately after the big bang, to relics...

Hello, As per the title - my name is Nick. I am soon to enter my senior year of high school. I come here partly due to recommendation of my teacher. This year, my plan is to participate in my city's annual science and engineering competition, which is connected to the Intel International...

Homework Statement a black hole has schwarzschild radius of 15.4km what is the mass of the black hole in terms of the suns mass?Homework Equations Rsch = 2GM/c^2 The Attempt at a Solution I plugged values into the equation and isolated for M and it gave me a different answer. Idk how the suns...

I know that likening Black Holes to the Big Bang is common among laymen and that scientifically educated people quickly reply that they are completely different things. But I would like to understand better in which aspects are they similar and in which they are different. If we run the...

I have always been fascinated by black holes And I am sure that all the answers in physics are hidden in black holes... According to Einstein nothing can go faster than the speed of light, but nothing can escape black holes not even the light. Would it mean that the gravity resulting by a fall...

http://arxiv.org/pdf/1401.5761v1.pdf Abstract: It has been suggested that the resolution of the information paradox for evaporating black holes is that the holes are surrounded by firewalls, bolts of outgoing radiation that would destroy any infalling observer. Such firewalls would break the...

I just watched a popular science program entitled Super Massive Black holes that proposed the idea that galaxies were formed long ago from hydrogen gas clouds whose centers collapsed to become super massive black holes that then generated star formation and ultimately the formation of galaxies...

Classical calculated with Newton the escape speed is r = 2G.M/v2. With v = c that would be the same as the Scharzschild radius calculated with GR. Does that mean that Newton laws are still valid at (or just outside) this radius?

AFAIK black holes are factual, but i can not find physical proof of the singularity, apart from Einstein's theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense remnant core. If the core's mass is more than about three times the mass of the...

What happens to the higgs field around the event horizon of a black hole, or is this currently unknown? Does the higgs field permeate inside the event horizon? Can extreme gravity affect the field in some way by changing its properties?

black holes pulls light right, then when a black hole pulls photon will the speed that photon increase?

edguy99 submitted a new PF Insights post https://www.physicsforums.com/insights/animating-black-holes-singularities-infinite-force-gravity/ https://www.physicsforums.com/insights/wp-content/uploads/2015/05/graviytanimation-80x80.png...

ok, hear me out on a lymph, because I'm going to either be talking crap or something that sounds crazy either way... my question is: why does the phenomena of a black hole look so perfectly circular/spherical? now here's my reasoning spheres are the shape that takes the least energy to be...

Can someone please explain what a black hole is? I hear everyone speaking about it but have no idea what it is. Is it something where even speed of light becomes 0? How?

Hello, I remember hearing somewhere that it is possible to calculate the event horizon, I was just wondering if this is possible and what equations are used to calculate it.

Wouldn't this explain why galaxies with no black holes are so small?

All that I've read about black holes describe something so massive it's gravity overcomes all other forces and it causes a region of spacetime to develop that no particle or electromagnetic radiation can escape from. That explanation since it depends on mass makes no sense in regard to...

Hope this Link works. I thought this guy was great, for the layperson looking for more than the usual fluff. Might nice to give SITP some heavy "likes". Maybe they will do more. Sorry not sure what forum this was most appropriate for...

This paper http://arxiv.org/abs/1504.00263, Assessing inflow rates in atomic cooling halos: implications for direct collapse black holes, discusses formation of direct collapse black holes in the early universe. Supermassive black holes are the only reasonable explanation for quasers in the high...

Dr. Tom Maccarone is a coauthor of the paper, “Two stellar-mass black holes in the globular cluster M22”, and is Associate Professor,Department of Physics, at Texas Tech University at Lubbock Texas. The work is discussed in a popular form at "Physicists Find Black Holes In Globular Star...

Just curious... I mean they don't form inside the event horizon, so how would they form outside? How does accretion do this?

I have been thinking of how black holes help form galaxies and have come up with this idea. Now I will assume everyone who reads this knows about how black holes and quasars work. Now if you can imagine a quasar in the beginning, ie. Without the galaxy...

"The supermassive black hole is sucking interstellar gas, but at the same time it is affecting the star-formation history of the galaxy with its powerful winds," Tombesi said. "Astrophysicists describe this process as a feedback between the central supermassive black hole and the galaxy, which...

Hello geeks! I've reached that point in life, where I've to decide on what to study. The thing is, that I simply love the wonders and extremes of our universe, such as neutron stars, black holes etc. But the thing is, if you don't want to give lectures in a university or do research in black...

What would happen if there was a supernova explosion near a black hole ? Would it just sit there and absorb all the energy incident on it ? Or would it simply vaporize into elementary particles ? And if it does vaporize, could the remnants give us a clue as to the quantum state of matter inside...

Hello, Always looking for answers to my questions, I had some answers like what micro black holes possibly created at the LHC (if it does not evaporate) would put millions or billions of years to be dangerous? I would like to know why Sorry if I come to you Ps : sorry for the way I did not...

Wondering if it's possible that black holes create dark matter and dark energy from the matter and energy they consume. Then, inflation might slow when supply is low. This would support author Tarō Gomi's theory that "everyone poops." What role would time dilation play if that's what's...

hypothetically speaking, are white holes inside white holes possible? and also, are black holes inside black holes possible?