twin universe, geminal cosmology
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An alternative theory for spiral structure.
...This model provides a new perspective on spiral structure, attributing it to the interaction between the galaxy and its ghost matter environment. Françoise Combe's theory is based on the interaction between two populations: the galaxy's matter and an undetectable, cold hydrogen mass of unspecified origin. It should be noted that a two-population interaction model had already been suggested in 1986 in my comic book A Thousand Billion Suns, published by Belin.
...We conducted tests through 2D simulations. See: J.P. Petit and F. Landsheat: Ghost matter, astrophysics. 6: Spiral structure. [ Available on this site: Geometrical Physics A, 9, 1998.]
...No need to duplicate images. If possible, we will integrate onto the site a very suggestive animation showing the birth of a barred galaxy. We observe two regimes. First, a strong dynamical friction causes significant slowing of the galaxy. The bar forms very quickly, as do the spiral arms. The slowing then becomes negligible. The system persists for many rotations, sustained by tidal effects. See the subsequent figures in the cited article. Of course, these results must be treated with caution, as they are only 2D. Our computational resources do not allow 3D simulations. However, if a team were to take over, we would be fully willing to provide all necessary technical guidance.
...In "classical" simulations, the problem lies in ensuring the longevity of spiral arms. In any case, this phenomenon corresponds to energy dissipation. The galaxy's components—stars—acquire high velocities, leading to the disappearance of the spiral structure, which would therefore need to be re-established by a new influx of cold gas, for example.
...In our model, the ghost matter environment appears to act as a "potential barrier," preventing these objects from escaping. The galaxy thus retains its spiral arms for many rotations. However, this would require confirmation in 3D.
...As mentioned earlier, we now have two new collaborators working on these simulation issues, and we are hopeful about the results of these new studies (the sequence showing the formation of spiral arms in a galaxy dates back to 1994...). The computational power of new hardware, now accessible even to ordinary individuals, allows us to "play in the big league" using just a personal computer. With such systems, we can manage enough "point masses" to soon realistically represent galaxies—meaningfully, as two very different populations under various aspects:
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The "Population I," or halo population, composed of old stars (and globular clusters), whose trajectories significantly deviate from the equatorial plane.
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The "Population II," or disk population, dynamically grouping young stars and variable amounts of gas. This second set of masses is located very close to the galaxy's equatorial plane. It is within this population that spiral structure forms as a "density wave." This is a highly nonlinear phenomenon, even comparable to a "shock wave."
...On the other hand, spiral structure affects Population I relatively little, despite this population accounting for 90% of the galaxy's mass. It will be extremely interesting to finally get closer to astrophysical reality by representing the galaxy not with a single population of point masses, but with two.
The Radiative Phase.
Here, we return to the cosmological aspects of the model. As previously mentioned, the linear initial solution—where R and R* near t = 0 grow proportionally to time—presents problems. Such an expansion would be far too gentle to ensure the freezing of primordial nucleosynthesis. We were thus led to connect with earlier work from 1988–1989, integrated into the site:
J.P. Petit, Mod. Phys. Lett. A3 (1988) 1527
J.P. Petit, Mod. Phys. Lett. A3 (1988) 1733
J.P. Petit, Mod. Phys. Lett. A4 (1989) 2201
and with:
J.P. Petit: Twin Universe Cosmology: Astronomy and Space Science 226: 273–307, 1995 and [See on the site: Geometrical Physics A, 2.]
...The idea is then to suppose that physical constants depend on energy density. In earlier work, we showed that joint variations of physical constants could be considered, leaving all physical equations invariant (field equations, Schrödinger, Maxwell, etc.). We suggest that such a model might apply to the radiative phase, when energy-matter is primarily in the form of radiation.
...As we go backward in time, energy-matter density increases. When rr >> rm (when radiation energy density greatly exceeds matter density), we arrive at the following laws:
...G being the gravitational constant, m the mass, h Planck's constant, c the speed of light, and e the electric charge. We take these quantities equal in both sheets (without justifying such a choice).
...Before describing this model in greater detail, let us provide its justification. As noted earlier, the remarkable homogeneity of the early universe—reflected in the 2.7 K cosmic microwave background—was difficult to explain within the standard framework. Thus, a new model had to be added to the old Big Bang theory: inflation. For French speakers, this term is poorly translated. It comes from the English verb "to inflate," meaning "to expand." Therefore, we are led—despite heavy assumptions—to suppose that the universe underwent a fantastic expansion in its "very early" stages. This justifies its homogeneity. However, it should be noted that this is the only observational support for Linde's model, this inflation theory. The cost remains relatively high.
...Here, we consider that physical constants might depend on matter energy density beyond a certain threshold. This is no worse than the assumptions underlying inflation theory, all things considered. But the benefit is double:
- We justify the homogeneity of the early universe
- We obtain a redefinition of the time variable.
...For homogeneity, it is quite straightforward. In the standard model, with c constant, everything depends on comparing the horizon ct to the average distance between particles.
...In this new view, references [On this site: Geometrical Physics A, 3, 1998, figure 17] and [Geometrical Physics A, 6, 1998, figure 10], while keeping this chronological variable t:
...Cosmic homogeneity is thus ensured at all epochs. This difference arises because the speed of light c increases as we go further back in time. See Figure 5 of reference [On this site: Geometrical Physics A, 6, 1998].
A brief aside:
...For many years, we were "the oddballs who amused themselves by varying physical constants"—a research theme that was never taken seriously in France, particularly within CNRS circles. Many considered the idea utterly absurd "in the..."