Although the D4-D5-E6-E7-E8 VoDou
Physics model is NOT a SuperString
Theory, the nice math involved in String
Theory is relevant, although not as a "theory
of elementary particles". In the
D4-D5-E6-E7-E8 VoDou Physics model, **closed strings represent
the world-lines of fermion particle-antiparticle pairs
**( the pair of fermions acting as a boson so that
the entire string is bosonic ) **from the time of their
creation to their eventual mutual annihilation**
(perhaps with lots of interactions with lots of other
particles/antiparticles of other world-lines in the meantime, and
with mutual creation/annihilation guaranteed by considering String
Theory spacetime to be a compactified 25+1 dimensional Minkowski
spacetime).

The D4-D5-E6-E7-E8 VoDou Physics model has:

whose Geometric and Physical Interpretations are:

Algebraic formulation of Bohm-many-worlds string quantum theory, timelike brane M-theory, and spacelike brane F-theory may be useful in sum-over-histories interpretations, particularly with respect to prime numbers and zeta functions.

Such String, M, and F Theories are used in my Quantum Consciousness paper contributed to Quantum Mind 2003.

26-dimensional String Theory and 27-dimensional M-theory can be represented by 3x3 Hermitian octonion matrices of the form:

a Y X Y* b Z X* Z* c

where X, Y, Z are 8-dim octonions, * is conjugation, and a, b, c are real numbers, which are independent for 27-dim M-theory, in which case they form the 27-dim Jordan algebra J3(O) and which sum to zero for 26-dim string theory in which case they form the 26-dim traceless part J3(O)o of that Jordan algebra. THE X, Y, Z COORDINATES FORM A CONFIGURATION SPACE for 1-particle states, in that, for a given 1 fermion particle: the octonion X determines a position in 4-dim spacetime and in 4-dim internal symmetry space; the octonion Y determines an identity as a fermion particle; the octonion Z determines an identity as a fermion antiparticle. The real numbers a, b, c are Auxiliary variables. 27-dimensional M-theory and 28-dimensional F-theory can be represented by 4x4 quaternion Hermitian matrices of the form:

a U T R U* b S V T* S* c W R* V* W* d

Here R, S, T, U, V, W are quaternions, * is conjugation, and a, b, c, d, are real numbers, and THE R, S, T, U, V, W COORDINATES FORM A CONFIGURATION SPACE for 1-particle states, in that, for a given 1 fermion particle: the quaternion R determines a position in 4-dim spacetime; the quaternion S determines in 4-dim internal symmetry space; the quaternion pair T, U determines an identity as a fermion particle; the quaternion pair V, W determines an identity as a fermion antiparticle. The real numbers a, b, c, d are Auxiliary variables. In this case, the 4x4 quaternion Hermitian matrices form the Jordan algebra J4(Q) (where I use Q to denote quaternion), and the theory is like A 28-DIM F-THEORY (if you recall, in the string theory community a few years ago F-theory was popular as a "generalization" of M-theory, with 1 more dimension than M-theory. 27-DIM M-theory itself can also be seen in terms of quaternions, by using the traceless J4(Q)o instead of J3(O).

Here are the Geometrical and Physical interpretations of:

Jordan algebra Lie algebra Sphere structure symmetry structure

26-dim Strings J3(O)o E6 / F4 Real S0 = {-1,+1} is boundary 78-52 = 26 of String Interval [-1,+1] ( closed string if you identify -1=+1 ) (Compare Graded Lie Algebra structure.)

In the D4-D5-E6-E7-E8 VoDou Physics model,closedstringsrepresent the world-lines of fermion particle-antiparticle pairs( the pair of fermions acting as a boson so that the entire string is bosonic )from the time of their creation to their eventual mutual annihilation,

* / \ ... / \ / / | (The illustrated closed string is red. \ | It interacts with a partially shown gray string.) \ / \... \ / *

perhaps with lots of interactions with lots of other particles/antiparticles of other world-lines in the meantime, so that part of each string might represent a photon or other particle of any type formed by interaction of one of the particle/antiparticle pair.Note that since our Universe began with a Big Bang, all its particles originate from pair creation since then. For pairs that do not appear to reconnect for mutual annihilation within the volume of 26-dimensional spacetime being considered in working with the String Theory,

**************** \ ... / \ \ / \ | (The illustrated string is red. \ | It interacts with a partially shown gray string. \ / \... A perfect absorber in the future \ / is indicated by ******* ). *

the string is closed by considering the 26-dimensional spacetime to be a compactified 25+1 dimensional Minkowski spacetime due to considering the Universe to "... be a perfect absorber in the future ...[as in]... the Wheeler-Feynman ... absorber theory of radiation ..." described by Narlikar in his book Introduction to Cosmology (Cambridge 1997) (Section 8.8.1) and related to the Collective Electrodynamics of Carver Mead. For most of the matter in our Galactic Cluster, such an absorber could be a Black Hole of the Black Hole Era. Such a compactification is also similar to the conformally compactified 3+1 dimensional Minkowski spacetime M# used by Penrose and Rindler in their book Spinors and Space-Time, Volume 2 (Cambridge 1986) (particularly Chapter 9). ]]

These Strings look like "world-line paths" of fermions in "configuration space-time" and their String Theory is the way to calculate the Generalized Bohm Quantum Potential that "tells" the fermion how to "move around" in configuration space is itself acted back on by the Fermion Configuration.

The Quantum Theory of the D4-D5-E6-E7-E8 VoDou Physics model has several ( in my opinion equivalent ) formulations, including Many-Worlds, Nelson's Stochastic Theory, and generalized Bohm Quantum Theory. In the generalized Bohmian point of view

"states of the physics model" are viewed as being completely determined by "configurations of fermions in configuration space",

which is consistent with the lattice physics view that

fermions live on vertices of the lattice, and gauge bosons live on links of the lattice,

so that gauge bosons can be represented in terms of fermions by the "state" of one fermion at the beginning of a link and of another fermion on a vertex at the end of a link, and composite bosons (like pions, which are pairs of quarks) can be represented in terms of their constituent fermions.

In other words, 26-dim String Theory can be interpreted as being the theory of movement of a "Bohm Point" in configuration space. ( Since I like to use a Lagrangian formulation using spacetime as opposed to a Hamiltonian spatial formulation with time as an "outside" variable, the configuration space is not particle positions (points) in fermion representation spaces, internal symmetry space, and spatial space but is particle world-lines (strings) in fermion representation spaces, internal symmetry space, and spacetime including both spatial dimensions and time dimension. )

If you look at String Theory as being analogous to General Relativity of a 26-dimensional SpaceTime, then you see that

- the Configurations correspond to General Relativistic Matter Fields and
- the Generalized Bohm Quantum Potential corresponds to Gravitation

so that the Quantum Theory is, like General Relativity, NonLinear in that the Generalized Bohm Quantum Potential (compare Gravitation) acts on the Configurations (compare Matter Fields) and the Configurations (compare Matter Fields) also act (by what Jack Sarfatti calls Post-Quantum Back-Reaction) on the Generalized Bohm Quantum Potential (compare Gravitation).

Jordan algebra Lie algebra Sphere structure symmetry structure

27-dim M-Theory J3(O) E7 / E6xU(1) Complex S1 is boundary J4(Q)o 133-78-1 = 54 = 2x27 of Unit Disk = 2-ball B2 Time Part of (2,4) vector space of Conformal Spin(2,4) (Compare Graded Lie Algebra structure.)

The (2,4) Conformal vector space corresponds to 6 of the 10 dimensions of the vector representation of the D5 Lie algebra of the D4-D5-E6-E7-E8 VoDou Physics Model. On those 6 dimensions, the Conformal Group Spin(2,4) = SU(2,2) acts linearly. The corresponding subspace of the 8 dimensions of the vector representation of the D4 Lie algebra of the D4-D5-E6-E7-E8 VoDou Physics Model is 4-dimensional Physical SpaceTime, on which the Conformal Group acts non-linearly.

The 2-ball B2 corresponds to the 2 Timelike dimensions of (2,4) Conformally Linear Physical SpaceTime.

The S1 boundary of B2 corresponds to the 1 Timelike dimension of (1,3) 4-dimensional ( Conformally non-linear) Physical SpaceTime.

These Timelike spaces look like p-Brane Membranes and their M-theory describes interactions among the Timelike parts of parallel material Brane Universes that Jack Sarfatti describes (in Decenber 2001 e-mail correspondence) as being "... next door to each other across thin Josephson tunnel "weak link" junctions in which Star Gates form ...".

Jordan algebra Lie algebra Sphere structure symmetry structure

28-dim F-Theory J4(Q) E8 / E7xSU(2) Quaternion S3 is boundary 248-133-3 = 112 = 4x28 of 4-ball B4 Spatial Part of (2,4) vector space of Conformal Spin(2,4) (Compare Graded Lie Algebra structure.)

The 4-ball B4 corresponds to the 4 Spacelike dimensions of (2,4) Conformally Linear Physical SpaceTime.

The S3 boundary of B4 corresponds to the 3 Spacelike dimension of (1,3) 4-dimensional ( Conformally non-linear) Physical SpaceTime.

These Spacelike spaces look like p-Brane Membranes and their F-theory describes interactions among the Spacelike parts of parallel material Brane Universes that Jack Sarfatti describes (in Decenber 2001 e-mail correspondence) as being "... next door to each other across thin Josephson tunnel "weak link" junctions in which Star Gates form ...".

Jack Sarfatti describes
(in Decenber 2001 e-mail correspondence) "...
The **parallel material "brane universes"**, next door to each
other across thin Josephson tunnel "weak link" junctions in which
Star Gates form ...". If you consider that new
Universes might form from Quantum Fluctuations in older
Universes, you can see that it might be reasonable to expect that
many **Parallel Material Universes** ( one of which might be Our
Universe ) might exist very close to each other, or intersect with
each other at **Intersection ****Star
Gates**.

Consider the following illustration, adapted from an Ann Feild STScI illustration of a Model of Expanding Universe:

The illustration shows only 3 levels of Universes, and so is much simpler than reality.

The illustration is a 2-dimensional projection of an embedding into 3 dimensions of a 2-dimensional ( 1 timelike, 1 spacelike ) universe, with only 2 spacelike dimensions of 4-dimensional Physical SpaceTime being suppressed, and so is probably not unreasonably unrealistic ( just replace a S1 circle "horizontal" cross-section of each universe with an S3 3-sphere ) if you restrict your viewpoint to only the 4 dimensions of 4-dimensional Physical SpaceTime.

However, for 27-dimensional J4(Q)o M-theory and 28-dimensional J4(Q) F-theory, another 23 (for J4(Q)o M-theory) and 24 (for J4(Q) F-theory) dimensions are suppressed in the illustration.

**Could ****those 23 or 24
degrees of freedom**** provide enough separation among the
Universes so that they are not really very close to, or intersecting
with, each other?** To answer that question, consider the physical
nature of those 23 or 24 degrees of freedom within the
structure of the Jordan algebra J4(Q) of 4x4 Quaternionic Hermitian
matrices:

a U T R U* b S V T* S* c W R* V* W* d

Here R, S, T, U, V, W are quaternions, * is conjugation, and a, b, c, d, are real numbers, and:

- the quaternion R determines a position in 4-dim Physical SpaceTime;
- the quaternion S determines in 4-dim Internal Symmetry Space;
- the quaternion pair T, U determines an identity as a first-generation fermion particle;
- the quaternion pair V, W determines an identity as a first-generation fermion antiparticle;
- the real numbers a, b, c, d are Auxiliary variables.

The dimensions of the 4-dimensional Physical SpaceTime that form the viewpoint of the above illustration of close neighbor/intersecting Universes are Large ( with respect to human experience ) Dimensions.

If the other 24 ( or 23 if a, b, c, d are not
independent, as in 27-dimensional J4(Q)o M-theory ) dimensions
are also Large, then maybe they could provide enough room for
separation among the Universes so that they are not really very close
to, or intersecting with, each other. Therefore, we need to ask:
**How Large are ****those
other 24 dimensions****?**

- As to 4-dim Internal Symmetry Space
(the quaternion S):
- Since dimensional reduction from 8-dim spacetime to 4-dim
Physical SpaceTime plus 4-dim Internal Symmetry Space occurs at
the Planck Energy ( about 10^19 GeV ), its size must be
**at least the Planck Length ( about 10^(-33) cm )**.It has compact geometric structure of CP2, on which color and electroweak gauge bosons are represented, whose size must be

**no greater than**- the radius of color confinement of color force gluon gauge bosons, which is on the order of a Fermi, or 10^(-13) cm., or
- the Compton Wavelength of any such gauge boson,
including the massive weak bosons whose Compton Wavelengths
are on the order of about
**10^(-16) cm.**

- Since dimensional reduction from 8-dim spacetime to 4-dim
Physical SpaceTime plus 4-dim Internal Symmetry Space occurs at
the Planck Energy ( about 10^19 GeV ), its size must be
- As to the
first-generation fermion particle representation space (the
quaternion pair T, U):
- It has compact geometric structure S1
x S7, with neutrinos represented on the S1 and charged
fermion particles represented on the S7,
- the size of the S7 being no greater than
- the Compton Wavelength of electrons, which is about 10^(-11) cm., or
- the radius of color confinement of up or down quarks,
which is on the order of a Fermi, or
**10^(-13) cm**., and

- the size of the S1 being no greater than the Compton Wavelength of the neutrino, which might be Large.

- the size of the S7 being no greater than

- It has compact geometric structure S1
x S7, with neutrinos represented on the S1 and charged
fermion particles represented on the S7,

- As to the first-generation fermion
antiparticle representation space (the quaternion pair V,W):
- It has compact geometric structure S1
x S7, with antineutrinos represented on the S1 and charged
fermion antiparticles represented on the S7,
- the size of the S7 being no greater than
- the Compton Wavelength of positrons which is about 10^(-11) cm., or
- the radius of color confinement of up or down
antiquarks, which is on the order of a Fermi, or
**10^(-13) cm**., and

- the size of the S1 being no greater than the Compton Wavelength of the antineutrino, which might be Large.

- the size of the S7 being no greater than

- It has compact geometric structure S1
x S7, with antineutrinos represented on the S1 and charged
fermion antiparticles represented on the S7,

- The Auxiliary variables ( the real numbers
a, b, c, d ) act as "glue" among all the various quaternionic
representation spaces, and are relatively unconstrained as to
their size-scale. If the 4 dimensions a, b, c, d of J4(Q)
Spacelike Brane F-theory are added to the 3 Spacelike dimensions
of Brane-Universes, then
**the 3-dim Spatial Manifold of All the Many Generations of Brane-Universes BU3, with all its complicated branching structure, can be smoothly embedded into an embedding target manifold space Mn = M7 with dimension n = (2x3+1) = 7 and basis Spatial x, y, z and Auxiliary a, b, c, d**, by the Smooth Embedding Theorem of Hassler Whitney (Ann. Math. 38 (1937) 809-818, Ann. Math. 37 (1936) 645-680)).If BU were N-dimensional, compactified and smooth, then by a theorem of

**John F. Nash, Jr.**, (Ann. Math. 56 (1952) 405-421) it could be realized as a sheet of a real algebraic variety in R^(2N+1).For an embedding to be isometric, if BU3 is smooth, a dimensionality of n = 3+(1/2)3(3+1) = 9 of an embedding target manifold Mn = M9 would be sufficient, according to the Isometric Embedding Theorem of

**John F. Nash, Jr**., (Ann. Math. 63 (1956) 20-63; Bull. AMS 60 (1954) 480), with a correction noted by Robert M. Solovay in 1998, and improvements as to the required number of dimensions as described by Deane Yang discussing work of Matthias Gunther (Matthias Gunther, Proceedings ICM (Kyoto 1990), Math. Soc. Japan, 1991, pp. 1137-1143).Marcel Berger says in his book (28 December 2001 version being proof-read by Benjamin McKay) Riemannian Geometry Today Introduction and Panorama at page 173: "... (Nash, 1956, and ... Various authors [who] have since improved N ... )

**Every smooth Riemannian manifold of dimension n can be smoothly isometrically embedded in E^N where N = (n + 2)(n + 3)/2**... We now know that abstract Riemannian manifolds are no more general than submanifolds of the various E^N . ... In very low differentiability, Nash in 1954 and Kuiper in 1955 obtained surprising results ... Any continuous embedding of a Riemannian manifold can be deformed into a C1 isometric embedding. In particular,**any n dimensional Riemannian manifold embeds C1 isometrically into E^(2n+1)**. ...".Y. Eliashberg N. Mishachev, in their book Introduction to the h-Principle, say: "... A C1-map f: V -> W is called strictly short if f*h < g ... It is well known from classical differential geometry that for r > 1 the Cr -smooth isometric immersions of two-dimensional Riemannian C1-manifolds into R^3 are very specific and rigid maps. For example, any isometric C2 -immersions of the standard sphere S^2 in R^3 into R^3 is congruent to the standard embedding S2 -> R^3 . Till the middle of 1950's mathematicians mostly believed that C1 -smooth isometric immersions V^n -> W^q are also rigid and hard to construct, and, in particular, the aforementioned uniqueness survives also for isometric immersions S2 -> R^3 which are only C1-smooth. It was discovered by J. Nash in 1954 that the situation is, in fact, drastically different when one passes to C1-smooth immersions. On contrast with C2 -immersions they appeared to be extremely flexible: ... (Nash-Kuiper)

**If n < q then any strictly short immersion f: (V^n, g) ->( R^q, h), where h is the standard metric on R^q , can be C0 -approximated by isometric C1-smooth immersions**. Moreover, if the initial immersion f is an embedding then f can be approximated by isometric C1-embeddings.**For example there exists a C1-isometric embedding of the standard sphere S^2 and the standard disk D^2 into an arbitrarily small ball in R^3**. Nash proved in ...[1954]... this theorem for n__<__q - 2 and later**Kuiper in ...[1955]... extended the theorem to the case n = q - 1**. The parametric version of the theorem is also true and implies ( together with the Example ... Given an arbitrarily C1-map f: (V, g) -> R^q , the composition Ha o f: (V, g) -> R^q , where Ha(x) = ax is a homothety centered at the origin, is strictly short for all sufficiently small a > 0. ... ) the following ...**Isometric C -immersions V^n -> R^q , n < q, satisfy the parametric h-principle for all Riemannian manifolds V = (V, g)**. ...**Homotopy principle (h-principle)**. We say that a differential relation R satisfies the h-principle, or that the h-principle holds for solutions of R , if every formal solution of R is homotopic in Sec R to a genuine solution of R. ... R satisfies the one-parametric h-principle if every family of formal solutions ... of R which joins two genuine solutions ... can be deformed inside Sec R , keeping ...[the two genuine solutions]... fixed, into a family ... of genuine solutions of R. ...**A partial differential relation R**is any condition imposed on the partial derivatives of an unknown function. A solution of R is any function which satisfies this relation. ... It is customary to visualize a map f: R^n -> R^q as its graph ... in R^n x R^q. ... Mathematicians call this map a section, while Physicists prefer to call it a field (or an R^q -valued field). ...".Nima Arkani-Hamed, Savas Dimopoulos, Gia Dvali, and Nemanja Kaloper, in hep-ph/9911386, say: "...We propose that our world is a brane folded ...[ or branched ]... many times inside the sub-millimeter extra dimensions. The folding ...[ or branching ]... produces many connected parallel branes or folds with identical microphysics ...[as in this illustration adapted from their paper:

with branching used instead of folding to produce ] ... - a Manyfold. Nearby matter on other folds can be detected gravitationally as dark matter...".

For an embedding of a pseudo-Riemannian manifold, such as the (1+3)-dim SpaceTime Manifold of All the Many Generations of Brane-Universes BU(1,3), Chris Clarke (Proc. Roy. Soc. A314 (1970) 417-428) gave a sufficient isometric embedding target manifold dimensionality of (2,89), or, if BU(1,3) were globally hyperbolic (1,88).

**( ****auxiliary a, b, c, d**** and
****neutrino S1 and antineutrino S1****
) **

**of the other ****24**
( or 5 of the other 23 if a, b, c, d are not
independent, as in 27-dimensional J4(Q)o M-theory )
**dimensions**** might be Larger than 10^(-16)
cm**.

**Conformal Gravity**at Larger Scales than our Solar System is described here.

**Strong Salam Gravity**at micron ( for electrons ) and nanometer ( for quarks ) is described here.

**Kaluza-Klein Gravitation of Extra Dimensions**is described here. With respect to Extra Dimensions, gravitational experiments have set additional upper limits on the size the two S1 fermion representation spaces of the neutrino and the antineutrino. For example, Mirabelli, Perelstein, and Peskin in hep-ph/9811337 have shown from present-day collider physics experimental observations that:**if 6 of the Kaluza-Klein extra dimensions ( such as****auxiliary a, b, c, d****and****neutrino S1 and antineutrino S1****) are large, they cannot be larger than 6.9 x 10^(-12) cm;****if 4 of the Kaluza-Klein extra dimensions ( such as****auxiliary a, b, c, d****) are large, they cannot be larger than 1.9 x 10^(-9) cm;****if 2 of the Kaluza-Klein extra dimensions ( such as****neutrino S1 and antineutrino S1****) are large, they cannot be larger than 4.8 x 10^(-2) cm.**

- "...
**The****Casimir force****with UXDs differs from the force obtained without extra dimensions**. ...", according to hep-th/0309066 by Poppenhaeger, Hossenfelder, Hofmann, and Bleicher, who said that there are some concepts of not only- "... compactified large extra dimensions (LXDs ...) in which only the gravitons can propagate ... [and] ... standard model particles ... are bound to our 4-dimensional submanifold, often called our 3-brane. ...", but also
- "...
**universal extra dimensions (UXDs) in which all particle species are allowed to propagate**. ... [for which] .... the present limit on the size of the extra dimensions is R__<__(300GeV)^(-1) = 10^(-9) nm due to the non-observation of Kaluza-Klein excitations at Tevatron ... the ... Casimir force ... data can be reproduced either ...... - by a calculation without UXDs ... or
- by a calculation with one UXD of size R = [about] 50 nm. ... For UXD sizes .... R = [about] (300GeV)^(-1) = 10^(-9) nm, the Casimir force is not in line with the measured data. ...".

Therefore, it seems to me that

**the Casimir force calculations and experimental data**, by requiring either an unrealistic UXD size of R = 50 nm or no UXD at all,**rule out the existence of UXDs in which not only Gravity, but also Standard Model particles and forces, propagate**. **Effects of the Bulk of Extra Dimensions on Gravity**are described by Thomas G. Rizzo in hep-ph/9903475: "... Arkani-Hamed, Dimopoulos and Dvali ... hypothesize the existence of n additional large spatial dimensions in which gravity can live, called 'the bulk', whereas all of the fields of the Standard Model are constrained to lie on 'a wall', which is our conventional 4-dimensional world. Gravity only appears to be weak in our ordinary 4-dimensional space-time since we merely observe it's action on the wall. ... a scenario of this type may emerge in string models where the effective Planck scale in the bulk is identified with the string scale. ... Gauss' Law ... provides a link between the values of ... the string or effective Planck scale in the bulk, Ms, ... the conventional Planck scale Mpl, and the size of the compactified extra dimensions, R,Mpl^2 ...[ is proportional to ]... R^n Ms^(n+2) where the constant of proportionality depends not only on the value of n but upon the geometry of the compactified dimensions. Interestingly, if Ms is near a TeV then R = 10^( (30/n) - 19 ) meters; for separations between two masses less than R the gravitational force law becomes 1 / r^(2+n) . For n = 1, R = 10^11 meters and is thus obviously excluded, but, for

**n = 2 one obtains R = 1 mm**, which is at the edge of the sensitivity for existing experiments ... For 2 < n ... the value of R is further reduced and thus we may conclude that the range 2__<__n is of phenomenological interest. Astrophysical arguments ...- [ by Schuyler Cullen and Maxim Perelstein, who say in
hep-ph/9903422:
"... Recently there has been a lot of interest in models in
which gravity becomes strong at the TeV scale. The observed
weakness of gravitational interactions is then explained by the
existence of extra compact dimensions of space, which are
accessible to gravity but not to Standard Model particles. In
this letter we consider graviton emission into these extra
dimensions from a hot supernova core. The phenomenology of
SN1987A places strong constraints on this energy loss
mechanism, allowing us to derive a bound on the fundamental
Planck scale.
**For the case of two extra dimensions we obtain a very strong bound of M > 50 TeV, which corresponds to a radius R < 0.3 micrometers**. While there are a lot of sources of uncertainty associated with this bound, we find that pushing it down to the few-TeV range, which could in principle be probed by ground-based experiments, is disfavored. For three or more extra dimensions the SN1987A constraints do not exclude a TeV gravitational scale. ...". ]

... suggest that

**Ms > 50 TeV for n = 2**, but allow Ms = 1 TeV for n > 2. ...".- [ by Schuyler Cullen and Maxim Perelstein, who say in
hep-ph/9903422:
"... Recently there has been a lot of interest in models in
which gravity becomes strong at the TeV scale. The observed
weakness of gravitational interactions is then explained by the
existence of extra compact dimensions of space, which are
accessible to gravity but not to Standard Model particles. In
this letter we consider graviton emission into these extra
dimensions from a hot supernova core. The phenomenology of
SN1987A places strong constraints on this energy loss
mechanism, allowing us to derive a bound on the fundamental
Planck scale.

**Effects of near-neighbor Branes on Gravity**are described by Stephen Hawking in his book The Universe in a Nutshell (Bantam 2001): "... Large extra dimensions ... would imply that we live in a brane world, a four-dimensional surface or brane in a higher-dimensional spacetime.**Matter and nongravitational forces would be confined to the brane.**...**On the other hand, gravity**...**would permeate the whole bulk of the higher-dimensional spacetime**... because gravity would spread out in the extra dimensions, it ... would fall off faster with distance than it would in four dimensions. ... If this more rapid falloff of the gravitational force extended to astronomical distances, we would have noticed its effect ... However, this would not happen if the extra dimensions ended on another brane not far away from the brane on which we live. ...... A second brane near our brane would prevent gravity from spreading far into the extra dimensions and would mean that at distances greater than the brane separation, gravity would fall off at the rate one would expect for four dimensions. ...

... On the other hand, for distances less than the separation of the branes, gravity would vary more rapidly. The very small gravitational force between heavy objects has been measured accurately in the lab but

**the experiments so far****would not have detected the effects of branes separated by less than a few millimeters**. ...... A black hole on a brane will extend to a black hole in the extra dimensions. If the black hole is small, it will be almost round; that is, it will reach about as far into the extra dimensions as its size on the brane. On the other hand, a large black hole will extend to a "black pancake", which is confined to a vicinity of the brane and which is much less thick ( in the extra dimensions ) than it is wide ( on the brane ) ...

... quantum theory means that black holes won't be completely black; they will emit particles and radiation of all kinds like hot bodies. The particles and radiation-like light would be emitted along the brane because matter and nongravitational forces like electricity would be confined to the brane. However, black holes also emit gravitational waves. These would not be confined to the brane but would travel in the extra dimensions as well. If the black hole [were] large and pancake-like, the gravitational waves would stay near the brane. This would mean that the black hole would lose energy ... at the rate one would expect for a black hole in four-dimensional spacetime. ...".

If two near-neighbor branes both had large pancake-like black holes at nearby spacetime regions, as in this illustration adapted from Hawking's illustration above,

then perhaps the gravitational interactions in the extra dimensions between the two black holes would create

a StarGate between the two brane-Universes.

......