A-L-E-X,
Planets with numbers as names are procedural.
Real exoplanets have letters, such as b, c, d, etc.

And apparently procedural planets are also displayed in the system browser when they are disabled.

Thanks, I was just going to ask about that.  And also procedural galaxies, quasars, stars, etc being with "R" something?

I see you have Kerr Black Holes listed.  These are the ones that can have traversable wormholes by physicist Kip Thorne

https://en.wikipedia.org/wiki/Kerr_metr ... _wormholes

Although the Kerr solution appears to be singular at the roots of Δ = 0, these are actually coordinate singularities, and, with an appropriate choice of new coordinates, the Kerr solution can be smoothly extended through the values of {\displaystyle r}[img=7x12]https://wikimedia.org/api/rest_v1/media ... 7c2a132538[/img] corresponding to these roots. The larger of these roots determines the location of the event horizon, and the smaller determines the location of a Cauchy horizon. A (future-directed, time-like) curve can start in the exterior and pass through the event horizon. Once having passed through the event horizon, the {\displaystyle r}[img=7x12]https://wikimedia.org/api/rest_v1/media ... 7c2a132538[/img] coordinate now behaves like a time coordinate, so it must decrease until the curve passes through the Cauchy horizon.
The region beyond the Cauchy horizon has several surprising features. The {\displaystyle r}[img=7x12]https://wikimedia.org/api/rest_v1/media ... 7c2a132538[/img] coordinate again behaves like a spatial coordinate and can vary freely. The interior region has a reflection symmetry, so that a (future-directed time-like) curve may continue along a symmetric path, which continues through a second Cauchy horizon, through a second event horizon, and out into a new exterior region which is isometric to the original exterior region of the Kerr solution. The curve could then escape to infinity in the new region or enter the future event horizon of the new exterior region and repeat the process. This second exterior is sometimes thought of as another universe. On the other hand, in the Kerr solution, the singularity is a ring, and the curve may pass through the center of this ring. The region beyond permits closed time-like curves. Since the trajectory of observers and particles in general relativity are described by time-like curves, it is possible for observers in this region to return to their past.
While it is expected that the exterior region of the Kerr solution is stable, and that all rotating black holes will eventually approach a Kerr metric, the interior region of the solution appears to be unstable, much like a pencil balanced on its point.^[12] This is related to the idea of cosmic censorship.



Overextreme Kerr solutions[edit]

The location of the event horizon is determined by the larger root of {\displaystyle \Delta =0}[img=44x17]https://wikimedia.org/api/rest_v1/media ... 7330ce5b58[/img]. When {\displaystyle {r_{s}/2}<\alpha }[img=63x20]https://wikimedia.org/api/rest_v1/media ... f3a10e3981[/img] (i.e. {\displaystyle GM^{2}<Jc}[img=77x19]https://wikimedia.org/api/rest_v1/media ... dbc0e199d9[/img]), there are no (real valued) solutions to this equation, and there is no event horizon. With no event horizons to hide it from the rest of the universe, the black hole ceases to be a black hole and will instead be anaked singularity.<sup>[11]

https://en.wikipedia.org/wiki/Naked_singularity

In general relativity, a naked singularity is a gravitational singularity without an event horizon. In a black hole, the singularity is completely enclosed by a boundary known as the event horizon, inside which the gravitational force of the singularity is so strong that light cannot escape. Hence, objects inside the event horizon—including the singularity itself—cannot be directly observed. A naked singularity, by contrast, is observable from the outside.</sup>

The theoretical existence of naked singularities is important because their existence would mean that it would be possible to observe the collapse of an object toinfinite density. It would also cause foundational problems for general relativity, because general relativity cannot make predictions about the future evolution ofspace-time near a singularity. In generic black holes, this is not a problem, as an outside viewer cannot observe the space-time within the event horizon.

Some research has suggested that if loop quantum gravity is correct, then naked singularities could exist in nature,^[1][2][3] implying that the cosmic censorship hypothesis does not hold. Numerical calculations^[4] and some other arguments^[5] have also hinted at this possibility.

The naked singularity hypothesis is disfavored by data from the first observation of gravitational waves.^[6]



[center][ltr]Contents
  [hide] [/ltr][/center]

• 1Predicted formation
• 2Metrics
• 3Effects
• 4Cosmic censorship hypothesis
• 5In fiction
• 6See also
• 7References
• 8Further reading

Predicted formation[edit]

From concepts drawn from rotating black holes, it is shown that a singularity, spinning rapidly, can become a ring-shaped object. This results in two event horizons, as well as an ergosphere, which draw closer together as the spin of the singularity increases. When the outer and inner event horizons merge, they shrink toward the rotating singularity and eventually expose it to the rest of the universe.

A singularity rotating fast enough might be created by the collapse of dust or by a supernova of a fast-spinning star. Studies of pulsars^{[citation needed]} and some computer simulations (Choptuik, 1997) have been performed.^[7]

This is an example of a mathematical difficulty (divergence to infinity of the density) which reveals a more profound problem in our understanding of the relevant physics involved in the process. A workable theory of quantum gravity should be able to solve problems such as these. ^{[speculation?]}

Shaw Prize winning mathematician Demetrios Christodoulou has shown that contrary to what had been expected, singularities which are not hidden in a black hole also occur.^[8] However, he then showed that such "naked singularities" are unstable.^[9]

Metrics[edit]
<sup>Disappearing event horizons exist in the Kerr metric, which is a spinning black hole in a vacuum. Specifically, if the angular momentum is high enough, the event horizons could disappear. Transforming the Kerr metric to Boyer–Lindquist coordinates, it can be shown[10] that the {\displaystyle r}[img=7x12]https://wikimedia.org/api/rest_v1/media ... 7c2a132538[/img] coordinate (which is not the radius) of the event horizon is

https://en.wikipedia.org/wiki/Kerr%E2%8 ... e_solution

An electron's a and Q (suitably specified in geometrized units) both exceed its mass M, in which case the metric has no event horizon and thus there can be no such thing as a black hole electron — only a naked spinning ring singularity.[14] Such a metric has several seemingly unphysical properties, such as the ring's violation of the cosmic censorship hypothesis, and also appearance of causality-violating closed timelike curves in the immediate vicinity of the ring.[15]

The Russian theorist Alexander Burinskii wrote in 2007: "In this work we obtain an exact correspondence between the wave function of the Dirac equation and the spinor (twistorial) structure of the Kerr geometry. It allows us to assume that the Kerr–Newman geometry reflects the specific space-time structure of electron, and electron contains really the Kerr-Newman circular string of Compton size". The Burinskii paper describes an electron as a gravitationally confined ring singularity without an event horizon. It has some, but not all of the predicted properties of a black hole.[16]</sup>

https://en.wikipedia.org/wiki/Ring_singularity

A ring singularity is the gravitational singularity of a rotating black hole, or a Kerr black hole, that is shaped like a ring.[1]

Contents  [hide] 
1 Description of a ring singularity
2 Traversability and nakedness
3 The Kerr singularity as a "toy" wormhole
4 Existence of ring singularities
5 See also
6 References
Description of a ring singularity[edit]
When a spherical non-rotating body of a critical radius collapses under its own gravitation under general relativity, theory suggests it will collapse to a single point. This is not the case with a rotating black hole (a Kerr black hole). With a fluid rotating body, its distribution of mass is not spherical (it shows an equatorial bulge), and it has angular momentum. Since a point cannot support rotation or angular momentum in classical physics (general relativity being a classical theory), the minimal shape of the singularity that can support these properties is instead a ring with zero thickness but non-zero radius, and this is referred to as a ring singularity or Kerr singularity.

Due to a rotating hole's rotational frame-dragging effects, spacetime in the vicinity of the ring will undergo curvature in the direction of the ring's motion. Effectively this means that different observers placed around a Kerr black hole who are asked to point to the hole's apparent center of gravity may point to different points on the ring. Falling objects will begin to acquire angular momentum from the ring before they actually strike it, and the path taken by a perpendicular light ray (initially traveling toward the ring's center) will curve in the direction of ring motion before intersecting with the ring.

Traversability and nakedness[edit]
An observer crossing the event horizon of a non-rotating (Schwarzschild) black hole cannot avoid the central singularity, which lies in the future world line of everything within the horizon. Thus one cannot avoid spaghettification by the tidal forces of the central singularity.

This is not necessarily true with a Kerr black hole. An observer falling into a Kerr black hole may be able to avoid the central singularity by making clever use of the inner event horizon associated with this class of black hole. This makes it possible for the Kerr black hole to act as a sort of wormhole, possibly even a traversable wormhole.[2]

The Kerr singularity as a "toy" wormhole[edit]
The Kerr singularity can also be used as a mathematical tool to study the wormhole "field line problem". If a particle is passed through a wormhole, the continuity equations for the electric field suggest that the field lines should not be broken. When an electrical charge passes through a wormhole, the particle's charge field lines appear to emanate from the entry mouth and the exit mouth gains a charge density deficit due to Bernoulli's principle. (For mass, the entry mouth gains mass density and the exit mouth gets a mass density deficit.) Since a Kerr ring singularity has the same feature, it also allows this issue to be studied.

Existence of ring singularities[edit]
It is generally expected that since the usual collapse to a point singularity under general relativity involves arbitrarily dense conditions, quantum effects may become significant and prevent the singularity forming ("quantum fuzz"). Without quantum gravitational effects, there is good reason to suspect that the interior geometry of a rotating black hole is not the Kerr geometry. The inner event horizon of the Kerr geometry is probably not stable, due to the infinite blue-shifting of infalling radiation.[3] This observation was supported by the investigation of charged black holes which exhibited similar "infinite blueshifting" behavior.[4] While much work has been done, the realistic gravitational collapse of objects into rotating black holes, and the resultant geometry, continues to be an active research topic.[5][6][7][8][9]

https://en.wikipedia.org/wiki/Rotating_black_hole

https://en.wikipedia.org/wiki/Naked_singularity#Effects

Naked singularity
From Wikipedia, the free encyclopedia
For the novel, see A Naked Singularity.
In general relativity, a naked singularity is a gravitational singularity without an event horizon. In a black hole, the singularity is completely enclosed by a boundary known as the event horizon, inside which the gravitational force of the singularity is so strong that light cannot escape. Hence, objects inside the event horizon—including the singularity itself—cannot be directly observed. A naked singularity, by contrast, is observable from the outside.

The theoretical existence of naked singularities is important because their existence would mean that it would be possible to observe the collapse of an object to infinite density. It would also cause foundational problems for general relativity, because general relativity cannot make predictions about the future evolution of space-time near a singularity. In generic black holes, this is not a problem, as an outside viewer cannot observe the space-time within the event horizon.

Some research has suggested that if loop quantum gravity is correct, then naked singularities could exist in nature,[1][2][3] implying that the cosmic censorship hypothesis does not hold. Numerical calculations[4] and some other arguments[5] have also hinted at this possibility.

The naked singularity hypothesis is disfavored by data from the first observation of gravitational waves.[6]

Contents  [hide] 
1 Predicted formation
2 Metrics
3 Effects
4 Cosmic censorship hypothesis
5 In fiction
6 See also
7 References
8 Further reading

Predicted formation[edit]
From concepts drawn from rotating black holes, it is shown that a singularity, spinning rapidly, can become a ring-shaped object. This results in two event horizons, as well as an ergosphere, which draw closer together as the spin of the singularity increases. When the outer and inner event horizons merge, they shrink toward the rotating singularity and eventually expose it to the rest of the universe.

A singularity rotating fast enough might be created by the collapse of dust or by a supernova of a fast-spinning star. Studies of pulsars[citation needed] and some computer simulations (Choptuik, 1997) have been performed.[7]

This is an example of a mathematical difficulty (divergence to infinity of the density) which reveals a more profound problem in our understanding of the relevant physics involved in the process. A workable theory of quantum gravity should be able to solve problems such as these. [speculation?]

Shaw Prize winning mathematician Demetrios Christodoulou has shown that contrary to what had been expected, singularities which are not hidden in a black hole also occur.[8] However, he then showed that such "naked singularities" are unstable.[9]

Metrics[edit]
Disappearing event horizons exist in the Kerr metric, which is a spinning black hole in a vacuum. Specifically, if the angular momentum is high enough, the event horizons could disappear. Transforming the Kerr metric to Boyer–Lindquist coordinates, it can be shown[10] that the {\displaystyle r} r coordinate (which is not the radius) of the event horizon is

{\displaystyle r_{\pm }=\mu \pm (\mu ^{2}-a^{2})^{1/2}} r_{\pm }=\mu \pm (\mu ^{2}-a^{2})^{1/2},

where {\displaystyle \mu =GM/c^{2}} \mu =GM/c^{2}, and {\displaystyle a=J/Mc} a=J/Mc. In this case, "event horizons disappear" means when the solutions are complex for {\displaystyle r_{\pm }} r_{\pm }, or {\displaystyle \mu ^{2}<a^{2}} \mu ^{2}<a^{2}.

Disappearing event horizons can also be seen with the Reissner–Nordström geometry of a charged black hole. In this metric, it can be shown[11] that the singularities occur at

https://en.wikipedia.org/wiki/Kerr_metr ... _wormholes

Symmetries[edit]
The group of isometries of the Kerr metric is the subgroup of the ten-dimensional Poincaré group which takes the two-dimensional locus of the singularity to itself. It retains the time translations (one dimension) and rotations around its axis of rotation (one dimension). Thus it has two dimensions. Like the Poincaré group, it has four connected components: the component of the identity; the component which reverses time and longitude; the component which reflects through the equatorial plane; and the component that does both.

In physics, symmetries are typically associated with conserved constants of motion, in accordance with Noether's theorem. As shown above, the geodesic equations have four conserved quantities: one of which comes from the definition of a geodesic, and two of which arise from the time translation and rotation symmetry of the Kerr geometry. The fourth conserved quantity does not arise from a symmetry in the standard sense and is commonly referred to as a hidden symmetry.

Overextreme Kerr solutions[edit]
The location of the event horizon is determined by the larger root of {\displaystyle \Delta =0} \Delta =0. When {\displaystyle {r_{s}/2}<\alpha } {r_{s}/2}<\alpha  (i.e. {\displaystyle GM^{2}<Jc} GM^{2}<Jc), there are no (real valued) solutions to this equation, and there is no event horizon. With no event horizons to hide it from the rest of the universe, the black hole ceases to be a black hole and will instead be a naked singularity.[11]

Kerr black holes as wormholes[edit]

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (February 2011) (Learn how and when to remove this template message)
Although the Kerr solution appears to be singular at the roots of Δ = 0, these are actually coordinate singularities, and, with an appropriate choice of new coordinates, the Kerr solution can be smoothly extended through the values of {\displaystyle r} r corresponding to these roots. The larger of these roots determines the location of the event horizon, and the smaller determines the location of a Cauchy horizon. A (future-directed, time-like) curve can start in the exterior and pass through the event horizon. Once having passed through the event horizon, the {\displaystyle r} r coordinate now behaves like a time coordinate, so it must decrease until the curve passes through the Cauchy horizon.

The region beyond the Cauchy horizon has several surprising features. The {\displaystyle r} r coordinate again behaves like a spatial coordinate and can vary freely. The interior region has a reflection symmetry, so that a (future-directed time-like) curve may continue along a symmetric path, which continues through a second Cauchy horizon, through a second event horizon, and out into a new exterior region which is isometric to the original exterior region of the Kerr solution. The curve could then escape to infinity in the new region or enter the future event horizon of the new exterior region and repeat the process. This second exterior is sometimes thought of as another universe. On the other hand, in the Kerr solution, the singularity is a ring, and the curve may pass through the center of this ring. The region beyond permits closed time-like curves. Since the trajectory of observers and particles in general relativity are described by time-like curves, it is possible for observers in this region to return to their past.

While it is expected that the exterior region of the Kerr solution is stable, and that all rotating black holes will eventually approach a Kerr metric, the interior region of the solution appears to be unstable, much like a pencil balanced on its point.[12] This is related to the idea of cosmic censorship.

A-L-E-X, I certainly understand your enthusiasm, but copy-pasting of entire pages from Wikipedia it's beyond the scope of this forum. A link to the original page is enough, and more readable.

Sorry about that, I think I got a bit off track there for a bit.  I just got really enthusiastic about the length and breadth of the effort, which is more than I've seen for any other program.  I have about a dozen different kinds of simulators, planetarium programs, etc., downloaded and nothing even approaches this.

I don't think a saturation slider is really necessary anymore as I've found B type stars to look quite blue, it's just that when you look at stars from a distance they all seem to be white.  When you get closer they take on a deeper color- I suppose this is good because this is how things work in nature.  How does one see the constellations as they appear from Earth, for example if I wanted to see Orion as seen from the Earth?

I guess there's only one place you have to go, the Earth. Use Shift-H three times to select Earth, (1. Milky Way, 2. Sun, 3. Earth), then press G to go, 2 times G to go faster.

And also procedural galaxies, quasars, stars, etc being with "R" something?

Yes. Procedural galaxies and quasars start with RG, stars, planets, planemos and brown dwarfs outside a star cluster starts with RS, stars, planets, planemos and brown dwarfs inside a star cluster start with RSC, clusters with RC, and nebulae with RN.

I don't think a saturation slider is really necessary anymore as I've found B type stars to look quite blue, it's just that when you look at stars from a distance they all seem to be white.  When you get closer they take on a deeper color- I suppose this is good because this is how things work in nature.

The "it's just that when you look at stars from a distance they all seem to be white" thing is caused by the desaturate dim stars setting in the graphics menu. If you don't want stars with low apparent magnitude to go white, try setting desaturate dim stars to the lowest possible, 0.01.

Also A-L-E-X, you seem to multipost a lot. I thought you needed to know that you can edit your posts with the pencil icon in the upper right of your post.

What if you put a procedural dense open star cluster made entirely of brown dwarfs inside nebulae that could be considered stellar nurseries? It would add to the realism no doubt. For example, a star cluster of brown dwarfs inside the Orion nebula would be called "Orion Nebula Cluster"

Here, I think I said this before on the old site, but I would really like "unique features". As in seperate surface modifiers to make planets more recognizable. When i look at the solar system, everything is unique, I feel this should be easier to recreate in space engine. Such as a Mountain{} tag or crater{} tag... (E.g. "Hey look I just found a selena with a single massive crater scretched across the surface"). Not necessarily just for procedural but also custom planets that still have a procedural surface. I just feel it gets repetitive after a while and if I could make out each object from a crowd that the engine would be much more engaging.

Hornblower,
I doubt that there is such a thing as cluster consisting only of brown dwarfs.
I can be wrong, of course.

The 'Orion Nebula Cluster' in any case is not made of brown dwarfs.
According to Simbad.

What if you put a procedural dense open star cluster made entirely of brown dwarfs inside nebulae that could be considered stellar nurseries? It would add to the realism no doubt.

Reality is that stars form with a distribution of masses described by an initial mass function, which I'm quite sure Space Engine already uses.  It is incredibly improbable to get a cluster of only brown dwarfs, or even only < 1 solar mass stars.

JackDole, Simbad has only the non-YSO stars in the group. YSOs far outnumber them. In other words, there would be about 400 red dwarfs and 7000 brown dwarfs in the cluster.

Watsisname, I mean if Vladimir incorporated it into the code to generate these specific types of clusters.