# The Naked Scientists Forum

### Author Topic: What is a ''naked'' singularity?  (Read 1895 times)

#### Thebox

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##### What is a ''naked'' singularity?
« on: 25/02/2016 10:07:51 »
Can somebody explain in their own words what a ''naked'' singularity is?

#### evan_au

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##### Re: What is a ''naked'' singularity?
« Reply #1 on: 25/02/2016 10:48:48 »
Wikipedia's words are better thought out than my words. Start reading here: http://en.wikipedia.org/wiki/Naked_singularity

#### Thebox

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##### Re: What is a ''naked'' singularity?
« Reply #2 on: 25/02/2016 10:55:18 »
Wikipedia's words are better thought out than my words. Start reading here: http://en.wikipedia.org/wiki/Naked_singularity

Thank you for your advice and I will take it step by step and ask each question every time I reach a point I don't understand.

I am at this point of one of the off links.

''A gravitational singularity or spacetime singularity is a location where the quantities that are used to measure the gravitational field of a celestial body become infinite in a way that does not depend on the coordinate system. These quantities are the scalar invariant curvatures of space time, which includes a measure of the density of matter. The laws of normal space time could not exist within a singularity''

Why would the laws of normal space time be any different to the laws of the ''naked'' singularity?

Doe's this also apply to axioms, like the speed of light?

#### the5thforce

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##### Re: What is a ''naked'' singularity?
« Reply #3 on: 25/02/2016 14:04:36 »
i interpret a naked singularity to be an "invisible" singularity that still distorts spacetime, perhaps a naked singularity is somehow attached to the surface of spacetime rather than hiding behind an event horizon

maybe a naked singularity is somehow inbetween states- not fully singular(decohered from spacetime) but not fully cohered to spacetime

for an in|credibly-con|fusing, intrinsically-nonsensical illustration:
« Last Edit: 25/02/2016 17:16:12 by the5thforce »

#### Colin2B

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##### Re: What is a ''naked'' singularity?
« Reply #4 on: 25/02/2016 15:30:10 »
i interpret a naked singularity to be an "invisible" singularity that still distorts spacetime, perhaps a naked singularity is somehow attached to the surface of spacetime rather than hiding behind an event horizon
As Evan says, it's worth reading the Wiki article as a starting point.

Why would the laws of normal space time be any different to the laws of the ''naked'' singularity?
Remember you have moved off naked singularity and followed a link to gravitational singularity, so what you are reading applies to all singularities.
If you think about what a singularity is - extremely dense matter where all the mass is concentrated in to a point - even movement must be difficult, imagine trying to move where all the atoms are crushed together! So all the physics and chemistry we know from normal spacetime will be difficult to apply.

Doe's this also apply to axioms, like the speed of light?
The speed of light is not an axiom, but again how does light propagate through a singularity? We certainly can't apply the normal laws of physics.

Can somebody explain in their own words what a ''naked'' singularity is?
This is a very difficult request. To explain anything to someone we usually have to asume some basic knowledge, plus you tend to use scientific words in nonstandard ways so there is a lot of opportunity for misunderstandings.

Most of the people here use their own words (and can feel insulted if accused of quoting Wiki or robotic words). However, many of those words are part of a common understanding. For example, if you were teaching someone to drive you would use standard terms eg brake, indicator, steer, and phrases eg apply the brakes gently. It is impossible to avoid using these.
If I have to look up a subject on Wiki I would be unlikely to respond to that question. If there were no answers forthcoming I might try to interpret Wiki to the level of understanding of the questioner, but that is hard to judge and it is impossible here to give a course in physics which might have taken someone 10yrs of study. In other words, some things are very difficult to answer in a forum like this, but I think most people will try their best and out of the goodness of their hearts and no intention to avoid the question or deceive.  Just something to bear in mind.

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#### Thebox

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##### Re: What is a ''naked'' singularity?
« Reply #5 on: 25/02/2016 16:53:48 »
i interpret a naked singularity to be an "invisible" singularity that still distorts spacetime, perhaps a naked singularity is somehow attached to the surface of spacetime rather than hiding behind an event horizon
As Evan says, it's worth reading the Wiki article as a starting point.

Why would the laws of normal space time be any different to the laws of the ''naked'' singularity?
Remember you have moved off naked singularity and followed a link to gravitational singularity, so what you are reading applies to all singularities.
If you think about what a singularity is - extremely dense matter where all the mass is concentrated in to a point - even movement must be difficult, imagine trying to move where all the atoms are crushed together! So all the physics and chemistry we know from normal spacetime will be difficult to apply.

Doe's this also apply to axioms, like the speed of light?
The speed of light is not an axiom, but again how does light propagate through a singularity? We certainly can't apply the normal laws of physics.

Can somebody explain in their own words what a ''naked'' singularity is?
This is a very difficult request. To explain anything to someone we usually have to asume some basic knowledge, plus you tend to use scientific words in nonstandard ways so there is a lot of opportunity for misunderstandings.

Most of the people here use their own words (and can feel insulted if accused of quoting Wiki or robotic words). However, many of those words are part of a common understanding. For example, if you were teaching someone to drive you would use standard terms eg brake, indicator, steer, and phrases eg apply the brakes gently. It is impossible to avoid using these.
If I have to look up a subject on Wiki I would be unlikely to respond to that question. If there were no answers forthcoming I might try to interpret Wiki to the level of understanding of the questioner, but that is hard to judge and it is impossible here to give a course in physics which might have taken someone 10yrs of study. In other words, some things are very difficult to answer in a forum like this, but I think most people will try their best and out of the goodness of their hearts and no intention to avoid the question or deceive.  Just something to bear in mind.

Thank you for the very considerate post, I have read some more and will watch a few videos later on to understand properly.

At this stage I am stuck on the thought of this ,

, '''the singularity is completely enclosed by a boundary known as the event horizon''

I can't help but to think that once the word enclosed is mentioned , it is sort of another firmament theory or flat earth theory based on finite observation?

added - does it mean , if I spun a football fast enough, it would turn into an invisible pancake?

« Last Edit: 25/02/2016 17:06:00 by Thebox »

#### Colin2B

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##### Re: What is a ''naked'' singularity?
« Reply #6 on: 25/02/2016 22:42:54 »
I can't help but to think that once the word enclosed is mentioned , it is sort of another firmament theory or flat earth theory based on finite observation?
I just see it as a boundary between two zones. Like the skin of a balloon encloses the air inside.

added - does it mean , if I spun a football fast enough, it would turn into an invisible pancake?
If you think about it, the earth is slightly flatter at the poles due to spin, so yes if you spun a football very fast it could in theory form a pancake, but not an invisible one. However, I think it would have blown apart well before that.

#### evan_au

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##### Re: What is a ''naked'' singularity?
« Reply #7 on: 26/02/2016 09:30:12 »
Quote from: Wikipedia
In a black hole, the singularity is completely enclosed by a boundary known as the event horizon
What makes the hypothetical naked singularity different is that the singularity would be exposed to space, and it might be possible to "see" infinity.

Physicists are divided on whether a naked singularity could exist; at least from the recent gravitational wave observations, we now know of two singularities that were hidden behind an event horizon.

The shape of the event horizon of a black hole is affected by the amount of spin (angular momentum) possessed by the black hole.

#### Thebox

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##### Re: What is a ''naked'' singularity?
« Reply #8 on: 26/02/2016 09:49:29 »
Quote from: Wikipedia
In a black hole, the singularity is completely enclosed by a boundary known as the event horizon
What makes the hypothetical naked singularity different is that the singularity would be exposed to space, and it might be possible to "see" infinity.

Physicists are divided on whether a naked singularity could exist; at least from the recent gravitational wave observations, we now know of two singularities that were hidden behind an event horizon.

The shape of the event horizon of a black hole is affected by the amount of spin (angular momentum) possessed by the black hole.

Well I have a good idea now what a ''naked'' singualrity is, I can visual describe it and from another forum I have had some relative maths that describe it in a  similar way  to my own idea about light radius.

If you can imagine a balloon  expanding, the ballons surface is the ''tip'' of the light, the surface of the ballon expands until it is ''transparent'' , the skin eventually fades out into nothing(darkness).

It is not enclosed, it is open but visually closed.   Between each naked singularity is a ''void'' of space, ''naked'' singularities can over lap, I.e we can see other naked singularity galaxies that overlap the milkyway.

That is how I picture it.

#### evan_au

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##### Re: What is a ''naked'' singularity?
« Reply #9 on: 26/02/2016 17:21:00 »
Quote from: TheBox
we can see other naked singularity galaxies that overlap the milkyway.
The overall density of the Milky Way (or other nearby galaxies) is way too low to form a singularity.

However, there is believed to be a regular singularity (a black hole) at the center of most spiral and elliptical galaxies, making up perhaps 0.1% of the mass of the galactic bulge.

For the Milky Way, the central black hole has a mass around 4 million times more than the Sun, crammed into a space that would fit into Mercury's orbit.

However, the rest of the galaxy (around 100 billion stars) is mostly empty space, which does not form a singularity. This is why galaxies are visible across space.

Quote
That is how I picture it.
That picture is nothing like what physicists mean when they imagine a naked singularity.
So don't call your mental picture a naked singularity.

#### The Naked Scientists Forum

##### Re: What is a ''naked'' singularity?
« Reply #9 on: 26/02/2016 17:21:00 »