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. T

    What is the motion of a singularity

    If all 4 dimensions of a singularity are zero. How do you describe the motion or evolution of a singularity, in space-time? For example the motion of a singularity, ie black hole at the centre of every Galaxy and Quasar as it evolves through space-time, if all it's 4 Dimensions are zero...
  2. H

    Proving the Existence of Event Horizon in Homogeneous Spacetimes

    Consider a Schwarzschild spacetime. If the singularity due to the point mass is removed (e.g. with an homogeneous matter distribution), does the event horizon disappear? If yes (I assume this is the case), how can be proven that there exists no event horizon if there is no singularity? May be it...
  3. A

    Exploring Ring Singularity of Spinning Black Holes

    Why does the point singularity of a black hole turn into a ring if the BH is spinning? What would the singularity look like if the BH were spinning on 2 axes? (What if the BH were really a multi-dimensional construct and were spinning on more axes?) What is the volume of a ring singularity...
  4. P

    Is Everything Still a Singularity?

    Hello I am new here. I have been wondering about the true nature of reality for some time, just because I am curious. Heres what i have concluded so far and i would like to know if there are any mistakes in it: The Big Bang started off as a singularity. Quantum mechanics has shown that...
  5. P

    Is the Singularity Still Present in Our Universe?

    Hello I am new here, I am a science and physics noob so please go easy on me. I have been wondering about the true nature of reality for some time, just because I am curious. During the proces I've come across the holographic universe theory, some quantum mechanics, some religious stuff, etc...
  6. N

    Atom of Singularity: Black Holes & Hydrogen Atoms

    What type of atom is a singularity primarily composed of? Hydrogen? So the fusion reactions in black holes lead to infinitely dense hydrogen atoms?
  7. R

    The End of the Universe from the Outside In - as free-faller nears singularity

    Consider a light source approaching a singularity (in free fall). As the source approaches the singularity, it is approaching infinite gravity, infinite tidal forces, infinite time-slowing, infinite escape velocity, and infinite red-shifting in zero distance (as seen, or not seen, by outside...
  8. R

    There is only one True Singularity and It is at the Center

    As I understand it, a gravitational singularity is a point where gravitational force is infinite and consequently time stops (from the viewpoint of any outside observer), light from a source at the singularity would become infinitely red-shifted after traveling zero distance (in other words...
  9. K

    Can Unknown Physics Explain the Singularity of a Black Hole?

    When a star of a few solar masses collapses and starts to form a black hole, if the particles of which the star was made get closer and closer together as the density increases, will there come a point at which no force mediating particles have a short enough wavelength to get between the...
  10. R

    Event Horizon vs Singularity: Are They the Same Thing in Black Hole Physics?

    Is the event horizon of a black hole (as seen by an observer at rest relative to the singularity) equivalent to the singularity (as seen by a free-falling observer)? In other words, if the stationary observer watches a rocketship free-fall to near the event horizon then turn on its rockets and...
  11. marcus

    Quantum Gravity: No BH Singularity with Modesto's Program - L. Modesto at MITP

    this just out L. Modesto, basically following Bojowald's program and a variant of it started by Husain and Winkler says he has gotten rid of the Black Hole Singularity by quantizing the spacetime model http://arxiv.org/gr-qc/0407097 this is what Bojowald did with the Big Bang...
  12. W

    Explaining Singularity: A Beginner's Guide

    I have been wondering for some time what a Singularity is, I have read it in various places around this forum but I don't understand. Could someone be so kind to explain that me? Forgive my ignorance, English is not my first language and I am new in all this.
  13. K

    Is there a limit to the validity of laws as the universe expands?

    Newton's law of gravity Force = Gm1 m2 / r^2, can be used to calculate the force that the universe as a whole exerts on a particle at its surface, provided a particle on the surface of a sphere containing the entire mass of the universe has a radius greater than 10^ 25 metres (it is currently...
  14. K

    Singularity prevented by repulsive force?

    If hadrons carried a new kind of charge that exerted a significant force only over very short distances so that hadrons repel hadrons at close range,this force could stop the formation of a singularity when a massive star collapses. There is no evidence for the existence of such a force...
  15. K

    Is the Singularity of a Black Hole Real or Theoretical?

    If a singularity is a point of infinite mass-density, this could mean there is a finite mass in zero volume or an infinite mass in a non-zero volume.Since a black hole does not have an infinite mass, does this mean it cannot have a singularity?
  16. T

    Black holes do not collapse to singularity>

    Please read this article: http://www.nature.com/news/2004/040712/full/040712-12.html I can't understand, which it says This suggests that black holes do not actually narrow to a singularity at all I can't understand, please explain :redface:
  17. marcus

    Loop Gravity cures brane collision singularity

    http://arxiv.org/hep-th/0407115 Loop Quantum Gravity and the Cyclic Universe Martin Bojowald, Roy Maartens, Parampreet Singh 6 pages, 4 figures Notice that Roy Maartens has published over 20 stringy-type papers, mostly on "brane-world" cosmology and brane-related matters. He now...
  18. wolram

    Naked Singularity: Is Event Horizon Observed or Hypothetical?

    http://relativity.livingreviews.org/Articles/lrr-2002-1/node3.html Im not sure if an event horizon has actually been observed, the article above talks about "naked singularities", I am wondering if the EH is only hypothetical, or if it is a basic property of BHs
  19. V

    Help for essential singularity problem

    Hello, can anyone help me out here? If you have a function f(z) in U, and b in U, such that b is an isolated essentially singular point for f(z) in U, what type of singularity can g(z) = 1/f(z) have?
  20. I

    The Big Bang: Inside a Singularity

    The big bang occurred after a singularity evaporated, correct? All that there was in the universe was "in" the singularity. So there was no space for the singularity to have curved. :confused: Also, when space time is curved, in what direction is it curved? or is that relative to the...
  21. T

    A naked singularity lies within the Sea of Dirac

    Hello all! I come in peace... sort of. :biggrin: As i was watching the anime Neon Genesis Evangelion, where one of the alien characters had the ability to capture its opponents in a Sea of Dirac, which was claimed to stretch over 800 meters in diameter, but had a thickness of only 3...
  22. J

    Is the Singularity similar to the Borg's collective consciousness?

    WHAT is the Singularity?? Is this like the Borg - collective consciousness??
  23. R

    Paper on the Singularity Resolution in Quantum Gravity?

    There has been an increase in the resolution of 'singularities'and the problems it brings. here is a link to a very "average" paper at present. The authors(no relation to ''Jeff'' I hope! seem to be grasping in the dark? Nevertheless, issue's are trying to be tackled from a number of...
  24. Adrian Baker

    Angular momentum of a singularity?

    We know that an ice skater pulling her arms in and spinning faster is an example of the conservation of angular momentum. As stars collapse to become Neutron stars, the rotational period can be as low as 0.001 seconds, again to conserve angular momentum. So what happens to this angular...
  25. H

    The Unexistence of Singularity Inside the Event Horizon

    All right, physicists claim that mass can be at infinite density. This condition is called the singularity, an one-dimensional point that is having mass (or energy, whatever)inside it. I say mass cannot possibly form singularities. Why? Because of the following: When there is mass inside...
  26. O

    Is a Technological Singularity Near, and How Can We Prepare for Its Impact?

    What are your thoughts on the future possibility of a technological singularity -- the creation of superhuman intelligence through technological means (such as artificial intelligence or augmentation of human brains)? This is discussed for example in...
  27. H

    Gravity Collapse on Planets: Physicists' Perspective

    Why does physicist only talk about gravity collpase on stars? Doesn't gravity collapse happen to planets? I mean they do not have any process such as nuclear fusion do repell gravity.
  28. A

    Is the Singularity Action Group Too Optimistic About Future Possibilities?

    http://www.singularityactiongroup.com Has anyone seen these people before? They seem a tad naive to me. On the front page is this quote: I was under the impression that the Singularity idea did not mean we would know everything, but that our science and tech would be advanced enough that...
  29. N

    Two Black Holes. No singularity.

    I watched a special recently in which there were two black holes observed and there was a single star between them. Instead of doing what a single black hole would do- pull the star into/onto it with it's imense gravity- the star stayed relatively the way it was because the black holes were...
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