Hawking Definition and 326 Threads

This question has bothered me sometimes. For 'standard' black hole with an event horizon, an external observer never sees matter cross the horizon (or get any signal from inside); while an infalling observer crosses the horizon and, for a very big black hole, may not even notice any extreme...

I've been wanting to read the book lately but before I do, I wish that some can give me a preview of what's ahead. What will be the major/interesting points of the books for someone like me who is just very interested with astrophysics and cosmology but doesn't have a lot of physics...

I haven't got a copy of Hawking's new book yet ('The Grand Design'), hoping I'll get it as a Christmas present :wink:. But i was quickly thumbing through it (mosly the side flaps) at the bookstore yesterday, and Hawking seems to subscribe to the 'Sum of Histories' theory (?), where the Universe...

I think it was proven that firing a photon (laser) straight up from the surface of Earth did in fact redshift the photon and decrease its frequency. And now, when we consider a black hole and Hawking radiation... I mean - the gravity inside the event horizon is so strong that EM cannot escape...

I don ` t understand Hawking` s answer to "Why this particular set of laws?". I read the book the grand design by Stephen Hawking. The book at the beginning say it attempts to answer three questions. The questions are: 1."Why is there something rather than nothing?" 2."Why do we exist?" 3."Why...

Hello, I didn't know where else to ask this, but I'm quite curious. What happens when two of the evanescent particles that Hawking describes, pop into existence at the same place and the same instant effectively overlapping each other? The source that sparked this question...

Didn't see a post about this yet. http://arxiv.org/abs/1009.4634

Hartle Hawking suggest probabilities for observations (eternal inflation picture) http://arxiv.org/abs/1009.2525 Eternal inflation without metaphysics James Hartle, S.W. Hawking, Thomas Hertog 4 pages (Submitted on 13 Sep 2010) "In the usual account of eternal inflation the universe is...

When i surf internet, i have meet a photo about Stephen Hawking and i have surprised when saw the Stephan Hawking standing. http://bit.ly/9VXk0Y

Okay, I've heard that in Stephen Hawking's new book, The Grand Design, he claims that the law gravity somehow created the universe from nothing. Can any of you give me a conceptual understanding of how this could occur?

Hawking singularity theorem -- what if not all geodesics incomplete? The Penrose singularity theorem tells us that once you get a trapped surface, at least one geodesic is guaranteed to be incomplete, going forward in time. But this doesn't mean that 100% of the mass of a collapsing star has to...

The theory of "Hawking radiation" says that black holes can emit different particles. We have a particle-antiparticle pair and one of them falls into the black hole while the other one escapes. On the other hand, we know that particles with color charge like quarks or gluons cannot travel...

I've read as much on the subject as I can before getting into the actual math of it, so I need people who know the subject better then I do to answer my question. The way I understand it, at the quantum level, particle/anti-particle pairs are created all the time and annihilate before they...

Hello, I've heard Hawking is giving a lecture this october in England (I myself am a Belgian) and I was wondering if it's worth the trouble to attend it? I'm a 2nd year college student and passionate about physics, but Hawking has never really gripped me, but that's maybe because I don't know...

Does anyone know the stances of prominent physicists (Susskind, Hawking, others) on hard determinsm?

Actual experimental aparatus, measurements and all that, see figure 2 on page 6 http://arxiv.org/abs/1008.1911 Measurement of stimulated Hawking emission in an analogue system Silke Weinfurtner, Edmund W. Tedford, Matthew C. J. Penrice, William G. Unruh, Gregory A. Lawrence (Submitted on 11 Aug...

I'm not quite sure how reliable http://library.thinkquest.org/C007571/english/advance/core4.htm" as a source but I thought it provided a good derivation for the Hawking Radiation equation relative to the Heisenberg uncertainty principle- First the energy of the radiation is established-...

Recently on my high school graduation an engineer uncle of mine gave me two books by hawking 1)God created the integers 2)On the shoulders of giants I have gone through the books but could not understand how will they be helpful in engineering please guide me how to use them to my benefit

If Hawking's model is correct then the universe could be regarded as a causally closed system, uncreatable and indestrucible.

So, when you plunge into a rotating black hole, according to penrose diagram one could travel to different universes, but at the same time black holes emit particles by hawking radiation. So what happens to an object inside the black hole? Do I make an error in reasoning somewhere?

For a [humorous let's hope] view from Stephen Hawking on alien life, check out: http://www.timesonline.co.uk/tol/news/science/space/article7107207.ece

Alternative to "God Created the Integers" ~ Stephen Hawking Hi! I was thinking about buying a decent book covering the history of mathematics (from a fairly technical point of view), and "God Created the Integers" by Stephen Hawking seemed to be the perfect book. However, after having read some...

Can someone give some opinions on the following? The 2 main arguments from this site i can tell are: that hawking radiation isn't proven. And that high energy collisions in the upper atmosphere travel at a fast speed & the small black holes can escape from Earth unlike in the lhc. I...

Does Hawking radiation account for the parity imbalance between matter and anti-matter? Do Black Holes create matter? If a matter/anti-matter pair materializes on either side of the event horizon of a black hole: 1) if the matter particle is on the inside of the event horizon, the mass of the...

1)when hawking first propounded this thermal radiation, he took into acount the the gravitational cllapse. so I am not sure, if we consider a stationary system, then there won't be any particle creation. Is this the case? because I think there will not be any mixing of posive and negative...

Score one for Perimeter, it would be great if Hawking Radiation is confirmed so he could receive a Nobel and be recognized before his health fails him. http://www.dailymail.co.uk/news/article-1254945/Stephen-Hawking-plans-leave-Britain-Government-cuts-science.html"

With the theory of Hawking Radiation, people generally say to imagine that the black hole has a temperature, so it must radiate heat. But, this really is not how it is said to work. The means by which the black hole evaporates is not that particles are actually coming out of it, or that it is...

Posted this on the Astrophysics page but I think it is more appropriate here... Last night in my calculus class I learned about radioactive decay, a nice example using radium. I was taught that the smaller the mass, the slower the rate of decay (or at least that's what I absorbed, I still...

Last night in my calculus class I learned about radioactive decay, a nice example using radium. I was taught that the smaller the mass, the slower the rate of decay (or at least that's what I absorbed, I still have to go over my notes again. Or does the rate not change, but the time it takes...

I see how it is derived for the BH and in case of Unruh effect. In Unruh effect it is a function of acceleration In case of BH distance to the event horizon plays important role What I can't find, however, how tidal forces should be taken into account. For example, in the universe with DE...

i have long been a skeptic of hawking radiation. i would like to explore my concerns, and see what your reaction is. the concept hinges around the idea of a spontaneous particle pair being created somewhere near the EH of a BH. radiation would occur if one of the particles manages to escape...

Hi All, Is Stephen Hawking still able to communicate with the outside world or has he become totally incommunicado? If he is able to communicate, is he still contributing to the field? Thank you, Bob

Hawking radiation is almost certainly not going to win him a Nobel prize, because experimental detection is beyond our technology. But how about the singularity theorem which he and Roger Penrose proved? This theorem convinced the physics community that black hole would indeed form in realistic...

I'm reading Hawking and Ellis, and on p.16 they say that "The subspace of T_p defined by \langle \omega,x \rangle=(constant) for a given one-form \omega, is linear." But in what sense is this true? For if the constant is non-zero, the 0 of T_p is not in the subspace, nor does it satisfy...

Hawking radiation is supposed to emanate from black holes because black holes have a temperature. A black hole has to be about 3 times the solar mass. A black hole with a few times the mass of the sun would have a temperature of only one ten millionth of a degree above absolute zero. This is...

Hawking radiation is standard thermal spectrum, thermal spectrum means it only can emit photon. why Hawking radiation contains other particles?(electron neutrino neutron proton etc)

typical poor science reporting on our national media - this time about HR on msnbc.com: http://www.msnbc.msn.com/id/32781964/ns/technology_and_science-science the article states: "Contrary to popular belief, black holes do not suck up absolutely everything around them. They actually emit a...

if light cannot escape a black hole then how do they emit stuff called hawking radiation.

Why does Stephen Hawking omit all mention Loop Gravity? I have read his popular books from Brief history of time to Universe in a nuthsell to "Stephen Hawking and the Theory of Everything" Stephen Hawking's Universe A Briefer History of Time From what I recall, he absolutely spends...

Some thought experiments and questions. I would much appreciate any comments on whether my analyses below are correct. 1. I am falling feet first into a black hole. An external observer will never see me fall past the event horizon. However, in my frame of reference I will fall past it in...

Q1 - hawking radiation hinges around spontaneous particle pair creation near the EH of a BH. the spontaneous pair can only exist for less than the Planck time. how can either of the particle pair travel a far enough distance in that ridiculously small amount of time to actually cross the EH...

How exactly is the amount of Hawking radiation emitted by a black hole related to it's mass/Schwarzschild radius/etc? Is there a formula relating the two for instance? (I'm trying to calculate the time it would take for one of the LHC black holes that will supposedly destroy the Earth - ad...

I'm trying to understand how Hawking radiation works but, as usual, most explanations are oversimplified so they don't appear to make sense. If I understood correctly, pairs of particles and antiparticles pop into existence everywhere in the universe all the time, and usually annihilate each...

Hi, I am struggling to understand Stephen Hawking's view of the universe as a 4D closed manifold. In a recent interview, I believe he had this to say: What I don't understand is how this theory is compatible with the scientific observation that the universe is expanding? I have 2 questions: 1)...

Hawking "very ill" http://www.google.com/hostednews/afp/article/ALeqM5jiBccToRoUY5q5S43UgUN8XUzHBw

I have a question concerning black holes and hawking radiation. I hope it is an adequate question and I pose it in the right section. Consider a free-falling observer 1 approaching the event horizon of a black hole. Evaluating his proper time, one finds that he crosses the event horizon...

I'm going to a talk he's giving tonight, and I don't want to offend him somehow. I also don't know if he actually can, practically speaking...

i will like to know whether Stephen William Hawking's theories about the black hole...because i was a ordinary person who want to know what is black hole is about...because i see a lot of articles about black hole but none of it i can understand so i hope somebody here can help me out by explain...

I've read that Hawking believes the Universe somehow prevents naked singularities, and made a bet about it with Kip Thorne. But it seems to me that if you take a static black hole and continually inject material into it with high angular momentum, eventually you would have a naked singularity...

Hey everyone, I'm new here. I'm currently a Grade 12 Student interested in Astrophysics, who has just recently applied to University (in Canada: UBC, UVic, UofT, UWO, Queen's, and York; all for Astrophysics and/or Astronomy, if anyone wants to give me advice on which one to choose, please do...