New Scientist SPACE - Mysterious ring of stars guards Andromeda's heart

Nick ha scritto:

The Milky Way's near-twin galaxy, Andromeda, harbors a supermassive black
hole at its core that is surrounded by an unexpected and unexplained disc of
young stars.


In the linked article it's said:

" The newly discovered disc is composed of over 400 very hot, young
blue stars, orbiting like a planetary system very close to the black
hole. That puzzles astronomers because the black hole's intense
gravitational field should have torn apart any clouds of matter long
before they could coalesce to form new stars. "

I'll try to explain in some alternative way.

Dennis W. Sciama published in 1952 the article "On the origin of
Inertia", where he formulated Mach's Principle by introducing a scalar
potential
PHI = - integral ( rho / r ) dV ,
with rho = matter density , r distance from the test particle
and dV the element of volume,
then he considered a near body with M mass at distance r and its
newtonian gravitational potential phi = M/r and he found (with c= light
speed and
G= Newtonian constant), in a inertial frame:

(PHI + phi)/c^2 = - 1 / G , or as PHI phi :
G / c^2 = - 1 / PHI

So the meaning of rest mass-energy of test particle of mass m
is given by: m c^2 = - G m PHI , that is the sum of all gravitational
potential from all other masses in the universe.

Some years later, Brans and Dicke formulated an extended theory of
gravity, starting it in likely way from this assumption:

c^2 / G = Sum of ( m(i) / r(i))

where r(i) are distances from the test particle (m not included in that
sum
of course)
so the "constant" G can be operatively defined and can change in both
space and time. Brans-Dicke's theory has not got a great success as no
appreciable variation of G inside our sun system has never been measued
till now.

But what about G varying in space, near a hyper-dense body?

Bashkov and Kozyrev have found (2000) that

"scalar field, inside the matter, has characteristics like gravitation
permeability of material similar electromagnetic permeability of
material in Maxwell theories of electromagnetism. Investigation of
obtained exact solutions for given functions of a matter distributions
in the Newtonian limit of Jordan, Brans - Dicke theory show the
efficient value of gravitation constant depends on density of matter,
sizes and form of object, as well as on the value of theories coupling
constant. That for example led to weakening gravitation
force in the central regions of a Galaxies. This assumption constitutes
the way to explain observed rotation curves of Galaxies without using
cold dark matter."

In particular they found that the effective "constant" G' goes near to
zero(!)
at the center of big concentrations of mass:

"For objects with constant density, when increasing a radius or
density of configurations the gravitation interaction inwardly objects
weaken."
But also in the general case of distribution of matter density:
" When increasing a distance between focuses of configurations
gravitation interaction inwardly objects decreases." (Bashkov and
Kzyrev, 2000, "Dark matter an effect of gravitation permeability of
material in Jordan, Brans -
Dicke theory.").

I'll give now an easy example without using any General Relativity
formalism.

We suppose c^2 / G = Sum of all (m_i / r_i) except the m of
test-particle
and consider m near a M . Even if this M was very big and near to m,
this would not appreciably change the Sum above. So, by definition the
effective G'
would be given by:

c^2 / G'(effective) = c^2 / G(universal) + M / r

from this we easily find, for r = R(M), ray of the body M :

G' = G / ( 1 + R*(M)/r )

where R*(M) = G M / c^2 is the "gravitational ray" of M (the half
of a Schwarzschild ray)

so G' would decrease to G / 1.5 if r = R(M) = 2 R*(M)
and to G/2 if r = R = R*.

If we suppose for simplicity an omogenean density inside the star with
mass M, we obtain , for r = R(M)

G' = G / { 1 + (R* / 2R) * [3-(r/R)^2] }

at the center:

G'(effective) = G (Newtonian) / (1 + 3R*/2R)

and if R(M) = R*(M)

G' = G / 2.5

All that above let me to deeply suspict we all have had a wrong idea of
"black holes" till now. If the star would collapse inside its
Schwarzschild ray, that is R R* , we should have immediately G' goes
to zero near the center.

As consequence, no "singularity" will be never formed. The error of
General Relativity Theory would be given by the assumption that G is
always and everywhere a true constant.

So I think that the disk of "blue stars" formed so near a "supermassive
black hole" is not so strange and mysterious at all. Very simply, the
effective G' that is the gravitational intensity becomes more and more
low at the center.

I think those giant blue stars are already "inside" the so called
"black hole" - that is not a black hole at all - so they are not
stressed so much as one would imagine till now. Unless observational
measures will demostrate that they have got tangential velocities very
near the light speed. But I suppose these velocities are lower than
expected by the extimated value of the SM "BH" around which they
orbite.

Best regards,

Attilio Alaimo ( )
technician at Physic dept.,
University of Perugia, Italy.