A
cosmological model: The twin bang. (p.4)
Gravitational instability
could be illustrated with a single population (of weighted balls), placed on
a supple mattress. If some heavy balls form a clump somewhere, they create
a depression in the mattress and tend to attract their neighbors. This
is called the accretion phenomenon.
...Similarly,
a system with a single population of ping-pong balls would also be unstable.
If some form a clump somewhere, they push the sheet up and attract their neighbors.
...With
these two populations (heavy balls and ping-pong balls) we simulate joint
gravitational instabilities. It can produce indifferently matter or ghost
matter clumps. In figure (156 ter) the simulation of joint instabilities giving
a ghost matter clump (ping-pong balls' clump), with reinforced confinement
(by heavy black balls).
...In
1994 we began to study the behavior of such a system through 2d numerical simulations.
In papers:
- J.P.Petit & P.Midy: Repulsive dark matter. Geometrical Physics A,
3, section 3, figure 5.
- J.P.Petit & P.Midy: Repulsive dark matter. Geometrical Physics A,
4 Matter ghost-matter astrophysics.1.The geometrical framework. The
matter era and the newtonian approximation.
...Our
cosmological model shows that the matter density r and the ghost matter density
r* are different, due to the instability of the two universes' expansion process
( r* @ 64 r ). In addition the thermal velocity V*th in the twin fold F* was
found to be four times larger than the one in ours. We used two sets of 5000
interacting mass-points. In order to manage this mass density contrast we
"weighted" our mass-points through: m* = 65 m .
...3d-simulations
would require more points: beyond the possibilities of our system (now, in
April 1998, the situation is different: we have no system at all...).
...These
given results are nothing but a qualitative exploration of the system, with
mass-density contrast and different thermal velocities. We find that ghost
matter, the denser population, runs the game. As the accretion times are:
(156d)
ghost matter, having the smaller
one, forms clumps. The regular matter takes place in the remaining space. The
following figures come from:
J.P.Petit, P.Midy and and F.Landsheat: Matter ghost matter astrophysics.
5: Results of numerical 2d simulations. VLS. About a possible schema for
galaxies' formation. Geometrical Physics A, 8 , 1998.(157)
The two populations, together:
(158)
...Compared
to Mellot's simulations, based on Zel'dovitch pancakes theory, our structure
is remarkably stable in time. The lacunar distribution tends to keep the clumps
in place. Conversely, the clumps fix the lacunar structure in space. Each
acts on the other as a potential barrier. They mutually stabilize each other.
...Returning
to the heavy balls and ping-pong balls model we can schematize it, as shown
in figure (158 bis ). In order to simulate the mass density contrast we have
put small lead shots upon the linen.
...We
can imagine a different configuration, where the ghost matter is so hot that
its "Jeans' length" is larger than the tank's characteristic length. Then
the shots form a clump. See the depression in figure (158 ter). The presence
of the surrounding ping-pong balls modifies the side of the depression (its
slope) and reinforces the confinement effect.
...This
is a didactic model of a galaxy surrounded by hot ghost matter, which confines
it.
