Read about stephen hawking | 54 Discussions | Page 1

  1. S

    I The Multiverse and 'No boundary' conditions approach in cosmology

    Summary: Questions about the Multiverse hypothesis and the 'No boundary' conditions approach in cosmology I have some questions about James Hartle and Stephen Hawking's 'No-boundary' proposal: - In their approach multiple histories would exist. These histories could yield universes with...
  2. R

    B Can someone please explain this paragraph from A Brief History Of Time

    what does it mean when you say the stars all fall in on each other?And what does the line uniform distribution of stars outside this region mean?and what does this line mean- again fall in?what does fall in mean? would really appreciate some help in understanding the meaning in simpler words...
  3. Hawkingo

    Stephen Hawking predicted the future of mankind

    Well known scientist professor Stephen Hawking had predicted the possibility that genetic modification can give birth to superhumans that could destroy the rest of humanity. The essays, published in the Sunday Times, were written in preparation for a book that will be published on Tuesday. Read...
  4. A

    B Documentary about Hawkings contributions to science

    Hello Community, as mentioned above I am currently gathering information for a documentary about Stephen Hawkings scientific contributions. According to "The Guardian" the most important are: - Singularities in Gravitational Collapse -Blackhole mechanics -How Blackholes can vanish -How...
  5. Laurie K

    B Vale Stephen Hawking

    On Pi day and the anniversary of Albert Einstein's birthday, a great man, mathematician and scientist passed away. Vale Stephen Hawking. https://edition.cnn.com/2018/03/14/health/stephen-hawking-dead/index.html
  6. Borg

    A Stephen Hawking's doctoral thesis is available online

    Stephen Hawking makes his doctoral thesis available online Direct link to the paper: Properties of expanding universes
  7. Greg Bernhardt

    Insights Think You Know Stephen Hawking? - Comments

    TheAdmin submitted a new PF Insights post Think You Know Stephen Hawking Continue reading the Original PF Insights Post.
  8. RooksAndBooks

    News Donald Trump: What Do the Scientists Say?

    Donald Trump is a candidate running in the 2016 POTUS race. On 9/20/2016, 375 scientists signed an open letter regarding Donald Trump. I think it's interesting to read, since personally I do not see Trump as a viable candidate and the open letter addresses climate change and the United States...
  9. J

    Is Hawking's statement of Raychaudhuri's equation wrong?

    In Hawkin's lectures: http://arxiv.org/abs/hep-th/9409195v1, he states that the Raychaudhuri equation \dot \rho=\rho^2+\sigma^{ab}\sigma_{ab}+\frac 1 n R_{ab}l^a l^b with n=2 for null geodesics and n=3 for timelike geodesics. But in most places I've seen \dot \theta=-\frac 1 n...
  10. D

    Theoretical vs Experimental Physics

    I was watching a sixty symbols video on Stephen Hawking: , and it got me thinking. Is there any practical value for theoretical physicists, if what they are doing is simply speculation not backed by any data? I understand observing a physical phenomena, and from understanding it predicting new...
  11. Priyank

    The Multiverse

    People say that Multiverse doesn't exist, But as per #TheGrandDesign by Stephen Hawking, Quantum Fluctuations led to the creation of tiny universes out of nothing. A few of these reached a critical size, then expand in an inflationary manner, formed galaxies, stars and, in at least one case...
  12. bcrowell

    Were Hawking radiation and singularity thm controversial?

    I just saw The Theory of Everything, which is a Hollywood biopic about Stephen Hawking. Of course the physics content had to be watered down and made to serve dramatic and thematic purposes, but a couple of historical points seemed interesting and made me wonder whether they were real: 1...
  13. David Carroll

    Why is temperature inversely proportional to the horizon's area?

    As I posted in another thread, I'm giving the caveat that I am no physicist and have only a rudimentary knowledge of math. Anyway, I am currently reading a book called "Three Roads to Quantum Gravity" by Lee Smolin. I came across a section of the book that confused me. Namely, Dr. Smolin...
  14. A

    I have difficulty understanding quantum physics

    Like I was reading Stephen Hawkings and while I found quantum physics interesting, I had trouble truly understand it. I mean I know it's the study of very small particles and stuff like you cannot predict where an electron is if the more you know its velocity but I had trouble understand the why...
  15. C

    Please recommend pop sci books

    Here is what I have read: carroll, sean from eternity to here carroll, sean the particle at the end of the universe deutsch, david the fabric of reality gott, j. richard time travel in einstein's universe greene, brian the elegant universe greene, brian the fabric of the cosmos greene...
  16. enorbet

    Gravity Waves and Graceful Exit

    Recently reading the Scientific American article The Black Hole at the Beginning of Time, which at first glance made me wonder if they were bowing to pressure to increase circulation, did however get me to thinking about Inflation and Graceful Exit, a rather major problem. I understand that...
  17. twistor

    Hawking is still funny

    THAT'S AN EXTREMELY HILARIOUS INTERVIEW WITH STEPHEN HAWKING. What are your thoughts on it? https://www.youtube.com/watch?v=OPV3D7f3bHY
  18. N

    If black holes don't exist then neither does the cosmic horizon?

    So according to Stephen Hawking, non-penetrable event horizons don't really exist. So by the same argument the cosmic event horizon can't exist either right? Only an "apparent" horizon which may hold information from outside the visible Universe for a short while until it enters the visible...
  19. 1

    Do famous physicists (Kaku and Hawking) pass off asumptions as fact?

    Hello all, I will freely admit I suffer from Obsessive Compulsive Disorder, and now that it is well managed I tend to attach my obsessions over interest. One thing I tend to obsess about is the possibility of aliens. I think about the fact that us humans are the only technological creatures on...
  20. N

    Any recommendtions for self-studying physics?

    I'm currently finishing my grade 11 year of high school and I have hopes of attending one of the prestigious schools in the US such as MIT, Harvard, Stanford, Princeton, etc. I would love to be able to study physics in university and, since my school's physics courses are lacking any significant...
  21. wolram

    Sir Roger Penrose

    http://www.sciencefriday.com/segment/04/04/2014/sir-roger-penrose-cosmic-inflation-is-fantasy.html What does Sir Roger know that others do not. Sir Roger Penrose calls string theory a "fashion," quantum mechanics "faith," and cosmic inflation a "fantasy." Coming from an armchair theorist...
  22. R

    Do all forms of energy behave like light?

    The idea of this question came from Stephen Hawking on a show on the Discovery channel called "Curiosity: Did God Create the Universe". Stephen Hawkings said that energy and space were the only ingredients necessary to create the universe: Do all forms of energy behave like light? Can all...
  23. S

    A Written Asignment About Time

    Homework Statement I was assigned to write sort of like an essay and the topic I was give is "Time". As simple as that. It needs to include front cover, introduction, body, references, conclusion, so on and so forth. It's due this coming Thursday. Homework Equations No equations...
  24. dheeraj

    Difference between micro black hole and primordial black hole

    If the amount of hidden information inside a black hole, depends on the size of the hole, one would expect from general principles, that the black hole would have a temperature, and would glow like a piece of hot metal. But that was impossible, because as everyone knew, nothing could get out of...
  25. zoobyshoe

    Hawking Says, There are no black holes.

    Hawking Says, "There are no black holes." More: http://www.nature.com/news/stephen-hawking-there-are-no-black-holes-1.14583
  26. J

    Almost uncontrollable fascination with astro/quantum physics

    I'm wondering if I'm alone, but I have this huge fascination with how the universe and everything works, like other dimensions, string theory, all that stuff. Basically everything that astrophysicist like Stephen hawking study. I would almost give up winning the lottery if I could know and...
  27. Integral

    Steve Hawking's new take on black holes

    In a recent paper Steve Hawking is reexamines black holes.
  28. rjbeery

    Black holes may not exist after all!

    I've posted a few threads over the years questioning the existence of black holes, and the response has been unequivocal defense of them... http://www.nature.com/news/stephen-hawking-there-are-no-black-holes-1.14583
  29. S

    White Holes created our Universe

    In general relativity, a white hole, is a hypothetical region of space-time which cannot be entered from the outside; but matter and light can escape from it. In this sense, it is the reverse of a black hole, which can be entered from the outside, but from which nothing, including light, has the...
  30. P

    Question about relativistic quantum hawking radiation.

    So as I understand it Stephen Hawking and one other person I can't remember the name of worked on an equation to described the "temperature" of a black hole, that you can actually get information out of it. I know that there is one way it could happen with those vacuum particles in vacuum energy...
Top