# Big Bang : Singularity or Singularities?

• Jozsef
In summary: That is because the singularity would exist in all directions at once, and there would be no unique location in an existing space.What people call a singularity (and what mathematicians call a “singularity”) is a point in space-time where the laws of physics break down. In the case of the Big Bang, the universe was said to have reached a point where the laws of gravity and other physical laws no longer applied.This is a very contested topic, as many mathematicians believe that there could be an infinite number of singularities, each with its own unique experience of the Big Bang. Some people even argue that there could be
Jozsef
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 that:
1) At the moment of the singularity there was no space-time and consequently no unique location in an Euclidean space.
2)To my opinion, a singularity also leads to the common misinterpretation that the Big Bang occurred somewhere ( anywhere you like) in an already existing space as a unique event in an already existing time.
Would it not be more enlightening to talk about Big BangS and singularitieS ? I mean that every observer, wherever in the universe, could be a singularity on its own and the center of its own Big Bang. Could it be that there are as many singularities and as many "experienced" Big Bangs as there are observers in the entire universe?
Quite controversial I know, but can anyone explain why this approach is potentially impossible?
Many Thanks, Jozsef

Jozsef said:
The Big Bang is often associated with the concept of a singularity. A singularity is defined as a point in space-time.
A singularity is a mathematical construct that may have any geometric distribution or none.

In GR, a singularity a result of a "geodesically incomplete" spacetime.
eg. a Kerr black hole has a gravitational singularity in the shape of a torus.
http://www.math.ucla.edu/~bon/kerroview.html

A singularity may be a point, but it does not have to be.
The singularity postulated at the big-bang being an example.
i.e. the big bang is something that happens everywhere.

2)To my opinion, a singularity also leads to the common misinterpretation that the Big Bang occurred somewhere ( anywhere you like) in an already existing space as a unique event in an already existing time.
The thing that leads people to think of the big bang as having occurred someplace in space is the name "big bang". It's suggestive of an explosion - people have seen explosions on TV, they all start out at some concentrated volume in space.
http://www.livescience.com/32278-was-the-big-bang-really-an-explosion.html

Would it not be more enlightening to talk about Big BangS and singularitieS ?
That just multiplies the problems and falls foul of Occams razor. The only need for this was if you thought that singularities had to be points.

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I think the problem here is that you are embedding the Big Bang into a geometric framework whereas our theories stop at the Big Bang event and can't proceed any further into the past before the event.

http://en.wikipedia.org/wiki/Big_bang

The view is that for us spacetime was created at the instant of the Big Bang.

Jozsef said:
A singularity is defined as a point in space-time. ...

The word "singularity" came into use in math over a hundred years ago, and was never intended to suggest a single point.

Back in the 1800s it meant "strangeness" "oddity" "weirdness".

Taken over into math it referred a breakdown or blowup in a mathematical theory, where some formula stopped giving reasonable numbers, or an equation stopped being solvable.

The word doesn't normally refer to anything in nature, or that really happens. It means failure or glitch in some man-made theory.

The popular media have misled the public into thinking that "singularity" refers to something real in nature which existed at a single point

Basically it is a problem in GR-based cosmology that people are working on getting rid of.
for a popular outreach essay about this from Einstein Institute, google "tale of two big bangs"

marcus said:
The word "singularity" came into use in math over a hundred years ago, and was never intended to suggest a single point.

Back in the 1800s it meant "strangeness" "oddity" "weirdness".

Taken over into math it referred a breakdown or blowup in a mathematical theory, where some formula stopped giving reasonable numbers, or an equation stopped being solvable.

The word doesn't normally refer to anything in nature, or that really happens. It means failure or glitch in some man-made theory.

The popular media have misled the public into thinking that "singularity" refers to something real in nature which existed at a single point

Basically it is a problem in GR-based cosmology that people are working on getting rid of.
for a popular outreach essay about this from Einstein Institute, google "tale of two big bangs"
Thank you Marcus, this is very clear to me, Jozsef

First of all, the name of this particular singularity is “the cosmological singularity” (unfortunately popular resources such as Wikipedia do not emphasise distinction between “a singularity” as a common noun, and this concrete thing; not such great minds as R. Penrose write these). Also, the cosmological singularity is the most obvious conjecture to explain the Big Bang, and the best theoretically substantiated, but not the only possible.

It is correct that, if the cosmological singularity existed, then it would be a misconception to think about it as about one point. From conformal point of view, it is a 3-dimensional space-like manifold forming a boundary of our universe (Ī once made this calculation, but didn’t publish it anywhere, although IMHO there are already many publications about it). One or many is a purely terminological quibble; Ī prefer to think about the singularity because there were no several discrete singularities.

## 1. What is the Big Bang Theory?

The Big Bang Theory is a scientific explanation for the origin of the universe. It proposes that around 13.8 billion years ago, the universe began as a singularity - a point of infinite density and temperature - and has been expanding and evolving ever since.

## 2. What is a singularity?

A singularity is a point in space-time where the laws of physics break down. In the context of the Big Bang Theory, it refers to the initial state of the universe where all matter and energy were compressed into an infinitely small and dense point.

## 3. Is there only one singularity in the Big Bang Theory?

The Big Bang Theory proposes that there was only one singularity at the beginning of the universe. However, some theories suggest the possibility of multiple singularities or other events that preceded the Big Bang.

## 4. What caused the singularity to expand?

The exact cause of the singularity's expansion is still unknown and is a subject of ongoing research. Some theories propose that it was triggered by a quantum fluctuation, while others suggest the influence of other dimensions or a cyclical universe model.

## 5. Can we observe the singularity?

No, we cannot observe the singularity directly as it is beyond the observable universe. However, scientists can study the cosmic microwave background radiation, which is considered a remnant of the early universe and provides evidence for the Big Bang Theory.

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