What is Singularity: Definition and 429 Discussions

A gravitational singularity, spacetime singularity or simply singularity is a location in spacetime where the density and gravitational field of a celestial body is predicted to become infinite by general relativity in a way that does not depend on the coordinate system. The quantities used to measure gravitational field strength are the scalar invariant curvatures of spacetime, which includes a measure of the density of matter. Since such quantities become infinite at the singularity point, the laws of normal spacetime break down.Gravitational singularities are mainly considered in the context of general relativity, where density apparently becomes infinite at the center of a black hole, and within astrophysics and cosmology as the earliest state of the universe during the Big Bang/White Hole. Physicists are undecided whether the prediction of singularities means that they actually exist (or existed at the start of the Big Bang), or that current knowledge is insufficient to describe what happens at such extreme densities.General relativity predicts that any object collapsing beyond a certain point (for stars this is the Schwarzschild radius) would form a black hole, inside which a singularity (covered by an event horizon) would be formed. The Penrose–Hawking singularity theorems define a singularity to have geodesics that cannot be extended in a smooth manner. The termination of such a geodesic is considered to be the singularity.
The initial state of the universe, at the beginning of the Big Bang, is also predicted by modern theories to have been a singularity. In this case, the universe did not collapse into a black hole, because currently-known calculations and density limits for gravitational collapse are usually based upon objects of relatively constant size, such as stars, and do not necessarily apply in the same way to rapidly expanding space such as the Big Bang. Neither general relativity nor quantum mechanics can currently describe the earliest moments of the Big Bang, but in general, quantum mechanics does not permit particles to inhabit a space smaller than their wavelengths.

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  1. BATMANofPHYSICS

    What happens to a person in free-fall at the center of the Earth?

    considering the Earth as a sphere, at the centre of the earth, by the equation F = G*m1*m2/r^2 , the gravitational pull experienced would be infinite . so assuming that we built a tunnel from 2 ends of the Earth through the centre, and a person jumps into the tunnel. till the centre of the...
  2. The Fishicist

    What Happens Inside a Black Hole?

    I'm curious about what others think. As I believe that you fall indefinitely in a black hole, and since you don't feel the gravity when falling, you fall until your incinerated by faster moving electromagnetic radiation falling on you. But you can only see what is above you, assuming your eyes...
  3. James S

    Black Hole Singularity: Infinite Mass & Merging Supermassive Black Holes

    If the Singularity Has Infinite Mass, How Does Merging With Another Black Hole Create "Suoermassive" Black Holes? Infinite Plus Infinite Is Infinite. No Increase.
  4. J

    Improper integrals: singularity on REAL axis (complex variab

    Hello everyone! I'm having some troubles when I try to solve improper integrals exercises that have singularities on the real axis. I have made a lot of exercises where singularities are inside a semicircle in the upper half side, but I don't know how to solve them when the singularities are on...
  5. A

    Can a singularity expand in volume?

    Can a singularity expand in volume?
  6. M

    Removable Singularity: Is it the Same as a Simple Pole?

    Hi guys, Is it right to say that a simple pole (pole of order 1) is a removable singularity (and vice versa)?
  7. Drakkith

    Size of the Observable universe at the Big Bang Singularity

    Just a quick question. How big was the current observable universe at the point in time where we reach 'singularity conditions' in the early universe? I'm assuming it can't be a single point, as there is no way that I know of to make a zero-dimensional point into a 3-dimensional object or space.
  8. C

    Penrose Diagram for the Kerr Black Hole

    Hey Guys, so i was reading Hawking&Ellis a bit and still encounter always problems with the Penrose-Diagrams. Looking at the Penrose-Diagram for the rotating Kerr-Black hole (just one illustrating picture at the end) i come up the following question: Why are there TWO regions III and III ? In...
  9. I

    Inside a black hole, looking out

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  10. zerospin

    Could black holes have no singularity?

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  11. J

    Compacting Matter in a Black Hole Singularity: Is It Pure Entropy?

    Information that is ordered can be compacted down to a single repeating unit i,e; 110055110055110055110055 down to just 110055 and this meant that it must have been highly ordered to be compacted down this far. So could it be that matter is also highly ordered somehow and it can be compacted...
  12. Doug Huffman

    Smolin dispelling false impressions of the singularity

    From Unger and Smolin's new The Singular Universe and the Reality of Time: A Proposal in Natural Philosophy, e-book page 403/576 "It is important to dispel some false impressions about the cosmological singularity theorems which are widely spread due to misleading accounts in some...
  13. A

    Can an AI write a credible novel with Wikipedia and YouTube?

    I always wanted to create a toolbox of critical analysis tools for young people to analyze, debate, and anticipate the near term future given our human nature and our history, especially since the scientific revolution. This is what my novel is intended to do, but writing a first (crap) edition...
  14. Q

    Could the mass of a singularity be described as an empty set

    Could the mass of a singularity be described or defined as an empty set, or else what is the term to describe it (in at least one sentence).
  15. bcrowell

    Were Hawking Radiation & Singularity Theorem Controversial in 1965?

    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...
  16. V

    Big Bang: A True Singularity That is Coordinate Independent

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  17. E

    Solving Removable Singularity in [z^(c-1)]/[exp(z)-1] at z=0

    How exactly would one show that [z^(c-1)]/[exp(z)-1]has a removable singularity at z=0? I tried using the methods introduced in my complex analysis book, but nothing seemed to work. Thanks!
  18. B

    Points of Analyticity and Singularity

    Homework Statement Determine the points for which ##f(z) = \frac{z^2 + 3}{(z-3)^2(z^2 - 4z + 5)}## is analytic and singular. Homework Equations Theorem 133: Suppose c is a complex constant and suppose the derivatives of the complex functions f and g exist at z. Then 1. Sums ##\frac{d}{dz}...
  19. HZY

    Why can the universe be expanding inward away from point of singularity (POS)?

    Much has been said about the universe expanding from a point of singularity (POS). But why can't the POS be a shell of singularity (SOS) such that the expansion would take place inside the SOS without breaking it. Did anybody thought about that?
  20. T

    Observing Kerr Singularity: What Would an Observer See?

    I know it is very unlikely such thing exists because QM can prevent CTLs However, what observer would see near such singularity? As ring is timelike, for an observer it won't be a ring at all, but a point, correct? That point should be visible (naked) because there are no horizons between an...
  21. P

    Representing distributed loads with singularity functions

    Homework Statement could someone explain why the terms in red represent the red distributed load in the attached diagram? Homework Equations http://postimg.org/image/3x0wywr4v/ The Attempt at a Solution the only term I think I understand is the -3<x-0>^0 but I'm not sure of the rest
  22. N

    Quantum Mechanics & General Relativity: Explaining the Singularity

    I keep hearing that QM and GR don't play well together. For example, a singularity, a result of GR, is small enough for QM to apply but...it doesn't. I was hoping someone could explain exactly where the "equations fail." Unfortunately I'm so ignorant in this subject matter that I can't be...
  23. P

    Plotting singularity functions

    Homework Statement Can someone explain how the expression for V(x) is plotted? Homework Equations The Attempt at a Solution I understand the plots for the dotted lines but not how they got the actual plot for V(x)
  24. N

    Solving for p at (0,0): Origin Singularity in f(x_1,x_2)

    Homework Statement Given the function f(x_1,x_2) = (x_1 - x_2^2)(x_1 - px_2^2) where p is a constant parameter, for what value of p will the origin (0,0) be a singular point of this function? Homework Equations The Attempt at a Solution I thought that singular meant...
  25. J

    Big Bang : Singularity or Singularities?

    The Big Bang is often associated with the concept of a singularity. A singularity is defined as a point in space-time. A common interpretation is that the concept of a point is meant to capture the notion of a unique location in an Euclidean space. This seems to me very misleading in as much...
  26. D

    Exponential integral over removeable singularity gives wrong result

    Hi, I am struggling for some time to solve the following integral: $$ \int_{-n}^{N-n} \left( \frac{e^{-j\pi(\alpha-1)\tau}}{\tau} - \frac{e^{-j\pi(\alpha+1)\tau}}{\tau} \right) d\tau $$ N is a positive integer, n is an integer, \alpha can be a negative or positive rational number. I want to...
  27. A

    MHB What Are the Singularity and Residue of \( \frac{e^{z^2}}{(z-i)^3} \)?

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  28. A

    MHB Yes, your solution is correct. Good job!

    Hello. Can someone check if I got the answer right? $f(z)=\frac{e^{-2z}}{(z+1)^2}$ My solution: $f(z)=\frac{e^{-2z}}{(z+1)^2}$ $$Resf(z)_{|z=-1|}=\lim_{{z}\to{-1}}\frac{d}{dz}((z+1)^2\frac{e^{-2z}}{(z+1)^2})$$ $$\lim_{{z}\to{-1}}-2e^{-2z}=-2e^{2}$$
  29. M

    Singularity and residue theorem

    Hello. Can someone check if I got the answer right? Find the singularity and the residue. ##f(z)=\frac{e^{-2z}}{(z+1)^2}## My solution: ##f(z)=\frac{e^{-2z}}{(z+1)^2}## $$Resf(z)_{|z=-1|}=\lim_{{z}\to{-1}}\frac{d}{dz}((z+1)^2\frac{e^{-2z}}{(z+1)^2})$$...
  30. C

    What happens if there is no singularity inside a black hole?

    Hello. I'm a layperson curious about physics. I've read that Quantum Gravity could eliminate the predicted singularity inside a black hole based on General Relativity. If that's true, what would happen from the frame of reference at the center of a black hole? Would that cause a tremendous...
  31. E

    Why does a singularity have to exist?

    Why, at the center of a black hole, does the need to be a point where space-time curvature is infinite? I understand that black holes scale with consumed matter, and that the point has 0 density but how do we get infinite G? I'm just an amateur but because this might just be a mathematical...
  32. I

    Derivatives of singularity functions

    Homework Statement Hello, I'm having trouble understanding this, seemingly simple, concept. Any help or input is appreciated. Evaluate the following derivatives: $$\frac{d}{dt} u(t-1)u(t+1)$$ $$\frac{d}{dt} r(t-6)u(t-2)$$ $$\frac{d}{dt} sin(4t)u(t-3)$$Homework Equations The Attempt at a...
  33. nomadreid

    Measurement of singularity as a particle inside event horizon

    Although the subject line might seem to put this question inside general relativity, the reason I put it in quantum physics is because I would like to know what happens when one treats a singularity as a particle. Obviously from outside the event horizon, one cannot do this, but inside the event...
  34. ChrisVer

    Understand Degeneracy of Metric at Schwarzschild Singularity

    I am reading this paper http://arxiv.org/pdf/1111.4837.pdf and I came across under eq12 that the new metric is degenerate... How can someone see that from the metric's form? Degeneracy for a metric means that it has at least 2 same eigenvalues (but isn't that the same for the Minkowski metric...
  35. S

    Cosmic inflation and singularity

    "Cosmic inflation" and singularity Hi. I saw this on Wikipedia: http://en.wikipedia.org/wiki/Chronology_of_the_universe#Planck_epoch Later: If there was no "traditional Big Bang" with inflationary cosmology, would this remove the singularity at the beginning of the universe? If so...
  36. N

    Is dimensionless singularity truly dimensionless?

    Hi, everybody. I have the question about initial, gravitational big bang singularity. My first question is if the universe was created from dimensionless singularity, is singularity truly dimensionless? Can extreme gravity truly destroy all that is (space, time, matter, energy, just about...
  37. S

    Singularity points + Laurent series

    Homework Statement Find and determine the type of singularity points for ##f(z)=\frac{\sin(3z)-3z}{z^5}##. Also calculate the regular and main part of Laurent series around those points.Homework Equations The Attempt at a Solution I am already having troubles with the first part. Singularity...
  38. E

    Find the Singularity function

    I was given the problem to: express the following signal in terms of the singularity function g(t)= t-1, 1<t<2 1, 2<t<4 4-t, 4<t<5 0, otherwise I graphed this function it is attached in below. My final answer for this function is g(t)=...
  39. dheeraj

    How Small Was the Big Bang Singularity When It First Exploded?

    hello everyone like the prevailing theory now on how our universe origin has taken is THE BIG BANG. BUT i am studying in 11th and one of my lecturer told me that our universe when exploded from the big bang singularity it's size was 10^-36 m any idea on that? like how scientists...
  40. J

    How is the Big Bang producing singularity not a black hole?

    Hey, so I've been wondering about this question for a while and was wondering if anyone could support the Big Bang theory in this respect or anything else. Just wondering if anyone has an answer that might aid me in understanding this, thanks.
  41. Einj

    Van Hove singularity for a two dimensional lattice

    Hi everyone. Suppose we consider an electron in a two dimensional lattice, whose dispersion relation is given by: $$ \epsilon(k_x,k_y)=-J(\cos(k_x a)+\cos(k_y a)), $$ and where the wave vectors belong to the first Brillouin zone (k_i\in [-\pi/a,\pi/a]). In this case it turns out that the...
  42. Low-Q

    What is the structure of a black hole's singularity?

    I have a couple of questions I cannot find a good answer to in the internet, so I ask you guys. I have heard about singularity as a infinite small point with infinite gravity - I talk about what I assume is the center of black holes. The scientist are talking about quantum gravity - the...
  43. A

    Conceptual problem on black hole singularity

    I've read that there's a point in a black hole where matter is infinitely dense. There is zero volume but infinite density. How is it possible for something to have zero volume but have an infinite density at the same time?
  44. J

    FRW Universe with Equation of State: Examining Singularity at Big Bang

    Does a FRW universe with the equation of state: $$p = -\frac{\rho c^2}{3}$$ have a singularity at the Big Bang? I was looking at: http://en.wikipedia.org/wiki/Penrose%E2%80%93Hawking_singularity_theorems and trying to decide if such a Universe obeys the "dominant energy condition"...
  45. S

    Singularity in black holes

    Gravity is zero at the center of the earth. how come the same set of equations predict the gravity to be infinity at the center of a black hole? where does the singularity really come into picture? how is a black holes center different from Earth's center?
  46. K

    Is there evidence of space surrounding the BB singularity?

    Is there evidence of space surrounding the BB singularity?
  47. A

    Understanding the Pole Singularity in Gradient of A

    in a text a read that " \oint \nabla A \cdot dl = 2 \pi n wich implies that the gradient of A has a pole singularity" why there is a singularity? I thing that this is a contidion to integral is nonzero but ¿what is the theorem used?
  48. T

    Singularity Mechanics? Blackhole Spin

    Singularity Spin Mechanics Okay I within the last week too a look at a article about black hole spin and in this article it was said by a scientist that black hole's spin near the speed of light that are supermassive blazars I was thinking if a object is spinning wouldn't that make this...
  49. A

    Seeking clarification on singularity at genesis

    Seeking clarification on singularity at "genesis" In Stephen Hawking's book, I read that there was no singularity in the beginning of the universe. However, practically every other source I come across seems to be under the impression that there was indeed a singularity before the big bang. I...
  50. marcus

    Common miscons (e.g. it exploded from a singularity) &why to check FAQ

    This is an idea for a thread. Might work or might not. Each post here should address a common misconception in 25 words or less. You don't have to restate the common misconception, just respond to it. I think we're all familiar with the main ones that keep coming up. Your post (if you...
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