Difference between revisions of "TFNR - Cosmic structures"
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*'''Gas Cooling and Star Formation''' | *'''Gas Cooling and Star Formation''' | ||
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| − | As matter accumulated within the gravitational wells formed by Dark Matter structures, vast clouds of gas began to cool and condense. This cooling allowed the gas to collapse under its own gravity, leading to the ignition of nuclear fusion in the first stars. These stars, formed in dense clusters within young galaxies, illuminated the dark universe. | + | As matter accumulated within the gravitational wells formed by Dark Matter structures, '''vast clouds of gas began to cool and condense'''. This cooling allowed the gas to collapse under its own gravity, leading to '''the ignition of nuclear fusion in the first stars'''. These stars, formed in dense clusters within young galaxies, illuminated the dark universe. |
| − | Over time, successive generations of stars enriched the interstellar medium with heavier elements forged in their fiery cores, further shaping the galaxies’ chemical composition and structure. Over billions of years, galaxies evolve as stars form, die, and enrich their surroundings. Spiral galaxies maintain their structure through ongoing star formation, while elliptical galaxies tend to host older stars and contain less gas. | + | Over time, '''successive generations of stars enriched the interstellar medium with heavier elements''' forged in their fiery cores, further shaping the galaxies’ chemical composition and structure. Over billions of years, '''galaxies evolve as stars form, die, and enrich their surroundings'''. Spiral galaxies maintain their structure through ongoing star formation, while elliptical galaxies tend to host older stars and contain less gas. |
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Revision as of 18:49, 18 July 2025
We have seen that celestial bodies or celestial objects in astronomy are considered as single and compact physical entities—components, bricks, building blocks—that make up the complex cosmic structures filling the Universe.
Cosmic structures are therefore more complex physical entities—structured and large arrangements / organizations of interconnected parts, objects, and bodies.
Some examples of the structures that populate the cosmos:
- Planetary systems
- Star clusters, filaments, flows
- Nebulae
- Galaxies
Just as planetary systems, star clusters, and other intragalactic structures—as well as nebulae— immersed in the dark turbulence of the Halo that hosts them, constitute the building blocks of galaxies, as we will see in the next section, galaxies are among the main building blocks of cosmic megastructures that compose the "universal (dark and visible) Cosmic Web".
Here, I will attempt to examine the most interesting cosmic structures for understanding the large-scale structure of the Universe: galaxies— medium-sized cosmic structures that can be considered true astronomical entities, bridging the gap between individual stars, stellar groups, on one side, and cosmic megastructures, on the other (groups and clusters of galaxies, superclusters, the cosmic web, etc.). As we will see, galaxies come in various shapes, sizes, and compositions—each playing a crucial role in cosmic evolution.
Let's examine galaxies in more detail, the strangest, most complex, and vastest structures listed here.
Galaxies
Generally, a galaxy is described as a massive system made up of stars, stellar remnants, interstellar gas, dust, and dark matter, all bound together by gravity. The order in which the supposed constituents of galaxies are listed reveals much about the current consolidated knowledge regarding the nature, structure, and dynamics of these fascinating celestial objects—the true cosmic building blocks. Dark Matter, listed last, is often treated as a kind of necessary evil—invoked to account for the bizarre dynamics of visible matter. In particular, we refer to the discrepancies between expected and observed values in the rotation curve of galactic material as a function of distance from the center in disk galaxies.
Although difficult to accept, to understand the nature, structure, origin and dynamics of these celestial objects we must recognize the central role played by Dark Matter and, given the hypotheses we have formulated regarding it, also Dark Energy. These highly structured objects are more than collections, aggregates of gas, dust, rocks, stars, planets, etc. They come in different shapes and sizes, from sprawling spirals like our own Milky Way to densely packed ellipticals and chaotic irregular galaxies. There are billions of galaxies in the Universe, each holding billions—or even trillions—of stars. Galaxies can also be grouped into clusters and superclusters, forming some of the largest structures in the cosmos. Their study helps astronomers understand cosmic evolution, dark matter, and even the fate of the universe itself.
Although difficult to accept, to truly understand the nature, structure, origin, and dynamics of these celestial objects, we must recognize the central role played by Dark Matter and, given the hypotheses we have formulated regarding it, also Dark Energy, which represents its counterpart. These highly structured entities are more than mere collections or aggregates of gas, dust, rocks, stars, planets, etc. They come in various shapes and sizes—from sprawling spirals like our own Milky Way, to densely packed ellipticals, and chaotic irregular galaxies. There are billions of galaxies in the Universe, each containing billions—or even trillions—of stars. Galaxies themselves can be grouped into clusters and superclusters, forming some of the largest known structures in the cosmos. Their study helps astronomers understand cosmic evolution, Dark Matter and its distribution, and even the ultimate fate of the Universe itself
Classification
Depending on their shape, structure, and dynamics, we can identify the following types of galaxies:
- Spiral galaxies – Characterized by rotating spiral arms of stars, gas and dust, extending from a central bulge. The Milky Way and Andromeda are clear examples. These galaxies often contain both young and old stars, with active star-forming regions in the arms.
- Elliptical galaxies – More spherical or elongated, smooth, round, or oval-shaped, and lacking spiral arms. They contain older stars and have very little gas and dust.
- Irregular galaxies – Chaotic in appearance, with no defined shape. Often formed or influenced by gravitational interactions, mergers, or collisions. They contain both young and old stars and are sometimes rich in star-forming regions.
- Lenticular galaxies – They possess a disk structure but lack prominent spiral arms. Mostly composed of older stars, with limited amounts of gas and dust. Often considered transitional forms in galactic evolution.
Each type of galaxy has a unique formation history and evolves differently, contributing in distinct ways to the structure and dynamics of the Universe.
Structure
Let’s take a look at the structure of a typical galaxy. We must think of a galaxy as a complex system, formed by a rotating bubble—not necessarily a perfect sphere—whose real shape is determined by internal turbulent dynamics, but above all by the external environment: interaction with other galactic bubbles, gravitational and magnetic effects within groups of galaxies, and more generally, turbulent dynamics within the cluster to which it belongs. This bubble is internally constituted by Dark Matter and bounded by Dark Energy, and—normally, though not necessarily—contains Ordinary Matter of various kinds and differently aggregated. All components are characterized by variously turbulent dynamics, with Ordinary Matter and Energy entering and exiting (e.m. radiation, particles, gas, dust, stellar bodies, black holes, etc.).
A rotating bubble, again not necessarily a perfect sphere, shaped by both internal and external turbulence, and by the interaction with other galactic bubbles, by gravitational and magnetic effects within groups of galaxies and more generally by turbulent dynamics within the cluster of which it is part. And in this complex turbulent dynamic, in the border regions of the galactic bubble—where the prevailing Dark Energy of interacting bubbles overlaps and influences their mutual position and movement—we find: smaller bubbles that constitute the dark structure of satellite galaxies, of dwarf galaxies that "orbit" the central galaxy. These systems, in turn, orbit along complex trajectories within larger dark structures, forming more extensive galactic groups, clusters, clusters of clusters, and so on. Turbulence within turbulence. Nothing could be further from the poetic (or sacred) image of the perfect celestial spheres—mirrors of divine perfection.
A galaxy is not what we see—the visible Ordinary Matter structures made of materials and objects, embedded in an invisible Dark Matter / Dark Energy Halo. A galaxy is the invisible Halo of Dark Matter and Dark Energy with some visible Matter that tends to gather in the central area of the bubble, in the "core". Under certain conditions, this Matter accumulates in a rotating disk around a supermassive black hole that is accreting at a more or less rapid pace, depending on the quantity and dynamics of the available material falling toward the galactic center.
In fact, the visible part—made up of Ordinary Matter and Radiation—represents only a small fraction of these cosmic objects. The most extensive, massive, and relevant part for their overall structure and dynamics is what we call "dark".
Calling the visible part "galaxy" (although understandable, given the history of the discovery of the existence of galaxies) is today a serious conceptual error, which leads to a series of logical errors that distance us from the possibility of understanding the nature and dynamics of the two fundamental components of what exists, of the Universe: Dark Matter and Dark Energy. The latter is not only a hypothetical form of Energy necessary to explain the phenomenon of cosmic expansion (among other things, an apparent phenomenon, which hides a very different nature and implications in cosmic evolution). Dark Energy is positive, repulsive Mass, a level of Perturbation higher than the universal average or an "extended neighborhood" of the region considered. It is the alter ego of the attractive Mass that is familiar to us, of which we are also made, in addition to all Ordinary and Dark Matter, visible and invisible.
Calling the visible part "galaxy"—although understandable given the historical context of their discovery—is today a serious conceptual error. It leads to a cascade of logical missteps that distance us from understanding the nature and dynamics of the two fundamental components of what exists, of the Universe: Dark Matter and Dark Energy. The latter is not merely a hypothetical form of Energy invoked to explain cosmic expansion (which, among other things, is an apparent phenomenon hiding deeper implications for cosmic evolution). Dark Energy is positive, repulsive Mass—a level of Perturbation higher than the universal average, or an "extended neighborhood" of the region considered. It is the alter ego of attractive Mass—the kind familiar to us, of which we are made. Along with all Ordinary and Dark Matter, visible and invisible, it composes everything that exists and forms the Universe.
Dark Matter and Dark Energy, intimately related components—two aspects of the same "substance"—are not only the dominant constituents in terms of quantity and Mass, but they are the most crucial elements for the structure and dynamics of a galaxy. Without DM and DE, the existence of a galactic bubble would not be possible.
The Dark Structure is foundational: it is the primary, constitutive part of the galaxy. The visible part of the galaxy forms because there is a bubble—represented by the Dark Halo—capable of triggering and guiding its formation processes. The dark and visible components coevolve in constructing the complex structure that is partly invisible and partly visible, which constitutes the galaxy. The Dark Halo is not composed of objects, Particles, or familiar materials. It consists of Dark Matter in the internal region (core) and Dark Energy at the boundary of the bubble(shell)—towards the outside, the extragalactic environment. The near-spherical boundary between the internal Dark Matter (negative Mass, Perturbation level lower than the average universal level or of the surrounding cosmic region, extended environment) and the surrounding Dark Energy (positive Mass, Perturbation level higher than the average universal level or of the surrounding cosmic region) is a surface with zero Mass.
I remind you once again that when I speak of the level of Perturbation, I refer to the so-called density of Elementary Events—the temporal distributions of elementary spatial fluctuations in resonance around the Planck scale. These temporal distributions can be lower, higher, or equal to the universal average, or to "local" averages of larger regions that include the region we are observing—in this case, a galactic bubble. According to the Principle of General Equivalence, a level of Perturbation greater or lower than the average (as mentioned, by Perturbation we mean the level of temporal distributions of Elementary Events) is equivalent to:
- a greater or lesser rate of temporal flow (rhythm of clocks)
- greater or lesser limit speed of the propagation of Causality / Action / Information in the Elementary Field
- a Field temperature higher or lower than the average
- and most centrally, in representing a massive structure such as a galaxy, to positive Mass (Dark Energy) or negative Mass (Dark Matter), respectively.
From this, especially when comparing the level of Perturbation of a specific region (e.g. a galactic bubble) with the universal average or that of the "extended neighborhood", it becomes evident that Mass (whether positive or negative) is an exquisitely relative concept. It depends on the reference frame assumed for its estimation, but above all, it depends on the relationship—the "relation" precisely—between the observed region and the surrounding one in which it is immersed.
In cases where a collision between two galactic bubbles causes the greater inertia of Ordinary Matter to eject it from the Dark Matter and Dark Energy bubble, we may "observe" an empty or partially empty dark galactic Halo. Next to it, we might observe a galaxy (the visible component) devoid of dark components—with consequent alterations in shape and rotation speed curve over a "cosmic" timescale, of course. Possibly, a merger of two disk/spiral galaxies into a single galaxy (ordinary matter, the visible part) with a "strange" shape, which over time will tend toward an elliptical form and, under the right conditions (progressive repositioning within a rotating dark bubble) and likely over a longer timescale, into a new and larger disk/spiral galaxy.
Due to the turbulent dynamics and interactions of these objects and their environments—as well as their age and the events that have affected them—galaxies can have various extensions (dwarf, normal size, extralarge) and shapes: regular (spiral, elliptical), irregular (colliding/merging galaxies), strange-shaped galaxies, etc. Oddly shaped galaxies appear to be the majority. Among them, we find galaxies with asymmetric disks—meaning not circular or not lying on a plane, etc. These asymmetries are very likely influenced by the internal dynamics of the galactic bubble, both in its dark and visible components, but especially by the interaction of the bubble with the surrounding environment—with other bubbles that interact with it and, more broadly, with the entire environment of the cluster and the section of the Cosmic Web to which it belongs.
As previously mentioned, it is truly difficult to determine the shape of galaxies—galaxies in the complete sense (DM/DE invisible Halo + Ordinary visible Matter/Energy). Dark Halos have shapes that depend on:
- internal factors: distribution of mass, total energy and its distribution, turbulence and internal rotation, interactions between dark and visible components
- external factors: gravitational, kinetic, chirality and spin of the bubble with the extragalactic/intergalactic environment, interaction with other galactic bubbles, friction of the boundary Dark Energy components, mass ratios between the bubble and surrounding ones, turbulent dynamics within the galaxy cluster, collisions, decelerations, etc.
Let's try to list the main galactic components (their presence, shape, composition, and dynamics depend on the type of galaxy):
- Dark (invisible) components
- Dark Energy shell – An invisible component forming the outer shell of the Dark Halo. It complements the inner core composed of Dark Matter. It influences the galaxy's gravitational behavior, but more importantly, its interaction with the extragalactic environment and the potential formation of new Ordinary Matter, which will be attracted toward the inner regions of the Halo.
- Dark Matter turbulent Halo – An invisible component occupying the inner part of the Dark Halo. It governs the formation, motion stability, and gravitational behavior of the galaxy. It is not merely "an invisible structure surrounding the galaxy", but a dark structure that permeates the entire inner region of the galaxy. It consists of a single Vortex-type InfoStructure of Dark Matter (widely extended, low density, turbulent, polydynamic), extending far beyond the internal region that hosts the structures of (visible) Ordinary Matter—the luminous galaxy we observe. The Dark Matter turbulent Halo can be detected through gravitational lensing and rotation curve studies.
- Ordinary (visible) components
- Gas and Dust Components – Clouds of gas and dust where new stars are forming. Unlike spiral galaxies, elliptical galaxies contain little gas and dust, limiting new star formation.
- Interstellar Medium (ISM) – The gas and dust spread throughout a galaxy, essential for star formation.
- Molecular Clouds – Dense regions where new stars form.
- Ionized Gas Regions – Found in active galaxies, often influenced by black hole activity.
- Stellar components – Young, hot stars in spiral arms; older, cooler stars in elliptical regions.
- Central supermassive black hole (SMBH) – A supermassive complex object with its accretion disc, jets, etc.
- Galactic Bulge – A dense central region containing older stars and normally a supermassive black hole, influencing the galaxy's dynamics.
- Galactic Disc – Found in spiral and lenticular galaxies, hosting younger stars, gas, and dust.
- Stellar Halo – A diffuse, extended region containing old stars, globular clusters, and dark matter. Stars in elliptical galaxies are more uniformly distributed, lacking a clear disk or arms. Most of these stars are older and redder, indicating minimal ongoing star formation.
- Large-Scale Galactic Structures
- Spiral Arms – In spiral galaxies, these curved regions contain young, hot stars, glowing nebulae, and star-forming regions. The arms appear brighter due to active stellar nurseries.
- Bars – Found in barred spiral galaxies, influencing gas flow and star formation.
- Rings – Some galaxies feature star-forming rings, possibly resulting from past interactions.
- Shells and Tidal Streams – Remnants of past mergers, visible in some elliptical galaxies.
- Gas and Dust Components – Clouds of gas and dust where new stars are forming. Unlike spiral galaxies, elliptical galaxies contain little gas and dust, limiting new star formation.
- Other components
- Kinematic and Dynamical Components
- Rotational Motion – Spiral galaxies rotate, while elliptical galaxies exhibit random stellar motion.
- Velocity Dispersion – Measures the spread of stellar velocities, crucial for understanding galaxy stability.
- Density Waves – Spiral arms are maintained by density waves, which trigger star formation.
- Magnetic Fields
- Galaxies possess large-scale magnetic fields that influence cosmic-ray propagation and interstellar matter dynamics.
- Typically measured in microgauss (µG), with spiral galaxies exhibiting structured magnetic field patterns along their arms.
- Kinematic and Dynamical Components
Physical quantities that describe structure, properties and dynamics of galaxies
In astronomy, different physical quantities are used to describe the properties and dynamics of galaxies. These fascinating systems are governed by a mix of gravitational, kinetic, chiral, magnetic, and quantum processes. Here are key parameters and how they are measured:
- Structural Parameters (define a galaxy’s structural properties)
- Extension (Size and Scale)
- Diameter – Measured in light-years (ly) or kiloparsecs (kpc) (1 kpc = 3,260 ly).
- Scale Length – The characteristic radius of a galaxy’s disc, useful for comparing galaxy structures.
- Galaxy Morphology – Classified using the Hubble sequence (e.g., Sa, Sb, Sc), based on the tightness of spiral arms and the size of the central bulge.
- Structural elements
- Spiral Arms – The number, shape, and pitch angle of the spiral arms.
- Bulge-to-Disk Ratio – The relative size of the central bulge compared to the disk.
- Galactic Disk Thickness – The vertical extent of the disk in relation to its diameter.
- Extension (Size and Scale)
- Gravitational and Kinematic Parameters
- Mass and Matter Composition
- Total Mass – Measured in solar masses (M☉), where 1 M☉ = the Mass of the Sun.
- Dark Matter Fraction – Determines how much of the galaxy’s mass is invisible, detected only through gravitational effects.
- Rotation and Velocity
- Rotational Speed – Measured in kilometers per second (km/s), indicating how fast stars and gas orbit the center.
- Rotation Curve – A plot showing how rotational velocity varies with distance from the center, crucial for studying Dark Matter distribution.
- Radial Velocity and Motion
- Redshift (z) – Determines how fast a galaxy is receding due to the expansion of the Universe.
- Radial Velocity – The speed at which a galaxy moves toward or away from Earth, measured via Doppler shifts in spectral lines.
- Velocity Dispersion
- In elliptical galaxies or galactic bulges, velocity dispersion measures the random motions of stars rather than ordered rotation.
- Expressed in km/s, higher dispersion indicates older, more stable galaxy structures.
- Chirality of Rotation
- Chirality refers to the handedness of a galaxy’s spiral arms (clockwise vs. counterclockwise).
- Statistically, galaxies don’t exhibit a universal preferred direction, but their Spin is influenced by formation history and surrounding structures.
- Studying galaxy chirality helps reveal large-scale cosmic structures asymmetries and structural evolution.
- Angular Momentum
- A key quantity describing a galaxy's rotation and Mass distribution.
- Defined by L = r × p (position vector × momentum).
- Influences galaxy evolution, mergers, and interactions with surrounding Matter.
- Magnetic Fields
- Galaxies possess large-scale magnetic fields that influence cosmic-ray propagation and interstellar Matter dynamics.
- Typically measured in microgauss (µG), with spiral galaxies exhibiting structured magnetic field patterns along their arms.
- Magnetic fields affect star formation, gas flow, and interactions between galaxies.
- Mass and Matter Composition
- Photometric Parameters
- Star Formation and Luminosity
- Star Formation Rate (SFR): Indicates how many stars form per year, measured in M☉ per year.
- Luminosity – Measured in solar luminosities (L☉), describing total Energy output.
- Surface Brightness and Luminosity Profile
- Surface brightness describes how light is distributed across a galaxy, measured in magnitudes per square arcsecond.
- Different galaxy types exhibit unique brightness distributions: exponential profiles in spirals, de Vaucouleurs profiles in ellipticals.
- Metallicity (Chemical Composition)
- Metallicity refers to the abundance of elements heavier than hydrogen and helium.
- Measured as metallicity fraction or [Fe/H] (iron-to-hydrogen ratio), useful for comparing stellar populations..
- Younger galaxies or star-forming regions tend to have higher metallicity due to stellar evolution enriching the interstellar medium.
- Star Formation and Luminosity
- Environmental Parameters
- Galaxy Environment – The influence of nearby galaxies, clusters, or intergalactic medium.
- Star Formation Rate – Often linked to gas density and the availability of molecular clouds.
Formation
Galaxies, the vast cosmic structures that host billions of stars, form through a complex interplay of gravitational forces—most of which are produced by turbulent Dark Matter Halos—and cosmic evolution. Understanding their formation provides insights into the origin of the Universe and its ongoing transformation / evolution. Below are the key stages of galaxy formation, each contributing to the magnificent structures we observe today.
- The primordial Universe and the role of Dark Matter and Dark Energy
In the infancy of the Universe (and here we are obviously not referring to the Big Bang, since this hypothesis is not compatible with the vision proposed by this research, which foresees infinitely long timescales for the formation of the current Universe—much longer than the age proposed by the Standard Model of Cosmology—Big Bang and Inflation), slight inhomogeneities in the distributions of Elementary Events—in the temporal distributions of elementary spatial fluctuations in resonance around the Planck scale—initiated turbulent dynamics in the Elementary Field. These dynamics led to the formation of the first impalpable and evanescent Structures of Information. The earliest forms of organization of infinitesimal inhomogeneities in vacuum density fluctuations within the "primordial cosmic soup" prepared the ground for the formation of Dark Halos, the invisible turbulent components of galaxies. As seen, my hypothesis is that these Dark Halos consist of an internal bubble of Dark Matter surrounded by an external shell of Dark Energy.
As these bubbles / Halos (voids) grew larger and more compressed within an increasingly crowded cosmos, their interactions became more frequent and intense, producing more friction. This triggered more or less powerful processes of formation of Ordinary (visible) Matter and Particles. Driven by the dynamics of the same dark bubbles and their immense—though rarefied—magnetic fields, these particles began to interact and combine, giving rise to composite particles, atoms, and eventually molecules. These gaseous materials began to fall into smaller (relatively speaking) dark bubbles—roughly the size of the Dark Halos of the galaxies we observe—and accumulated in filaments and nodes, in the interstices between large rotating voids.
Ordinary Matter, therefore, could not form galaxies on its own: the cosmic structure formed by Dark Matter played a fundamental role in its formation and aggregation. Dark Matter provides the gravitational scaffolding that allows Ordinary Matter to accumulate and form the visible part of the first galactic structures. Without invisible Dark Matter, galaxies as we know them would never have taken shape.
- Gas Cooling and Star Formation
As matter accumulated within the gravitational wells formed by Dark Matter structures, vast clouds of gas began to cool and condense. This cooling allowed the gas to collapse under its own gravity, leading to the ignition of nuclear fusion in the first stars. These stars, formed in dense clusters within young galaxies, illuminated the dark universe.
Over time, successive generations of stars enriched the interstellar medium with heavier elements forged in their fiery cores, further shaping the galaxies’ chemical composition and structure. Over billions of years, galaxies evolve as stars form, die, and enrich their surroundings. Spiral galaxies maintain their structure through ongoing star formation, while elliptical galaxies tend to host older stars and contain less gas.
Evolution
Like everything that exists, from the deepest and infinitesimal manifestations to the Universe as a whole, galaxies are also the object of an incessant evolution. Observing them in their majestic immobility can make us think of objects with a slow and monotonous life. Nothing could be more false. In a dilated temporal perspective (compared to the short average duration of human life), in the eternity that sees an infinite time of formation behind us, and equally infinite in the future, even the life of a galaxy, which seems so long to us, is nothing but the blink of an eye.
Over billions of years, galaxies grow, merge, and evolve, shaping the large-scale structure of the Universe. Galactic evolution is the process by which galaxies change over time, influenced by factors like star formation, mergers, and interactions with their environment. There can be many events that a galaxy can encounter both within itself as a single object, and as part of larger and more articulated structures (groups, clusters, the cosmic web, etc.). Collisions and mergers are those that seem to produce the most spectacular effects.
Galaxies rarely evolve in isolation. Instead, they continuously interact, often merging with neighboring galaxies in dramatic cosmic collisions. These mergers play a crucial role in the growth and transformation of galaxies, leading to larger, more complex structures. The gravitational upheaval from these interactions can trigger intense bursts of star formation, reshape spiral arms, and even alter the overall morphology of a galaxy. Some collisions may result in the formation of massive elliptical galaxies, while others enhance or disrupt existing spiral formations. Some galaxies evolve into spirals, like the Milky Way, while others become elliptical or irregular due to environmental factors and interactions. Many galaxies host supermassive black holes at their centers, which influence their evolution through powerful jets and radiation.
To understand mergers and the galactic evolution in general, it is essential to keep in mind that the galaxy is not what we see. This is only a part. And not the main one in terms of Mass, structure and dynamics. The turbulent Dark Halo, with its vortical sub-structures, dominates the formation as well as the evolution of the galaxy.
In particular, in collisions, due to the differences in size, and especially of density, the first structures to come into contact are precisely the dark structures, the part of the Halo made of Dark Matter surrounded by the shell of Dark Energy. It is precisely this shell, which in normal conditions is very extended and shows a very limited density of positive Mass, which, in compression conditions such as those that occur in the context of the approach and collision with the Dark Halo of another galaxy, in the contact region contracts and becomes denser, intensifying its repulsive force.
In the case of galaxies with discordant Chirality, i.e. both left-handed or both right-handed (if they were Elementary Particles we could say with equal electrical polarity) the gravitational attraction produced by the (negative) Masses of the combined Dark and Ordinary Matter of both galaxies would be much greater than the weak repulsion produced by the compression of their Dark Energy shells.
But in the opposite case, of two galaxies with concordant Chirality, like two electrical polarities that repel each other, the Dark Halos of the two galaxies, especially if of similar extension, Mass and therefore density of Mass, will repel each other more intensely. In this case, we could witness collisions in which the Dark Halos undergo a sort of rebound or deviation of trajectory, without undergoing a fusion. The visible components, the structures composed of Ordinary Matter (gas and dust, thick and thin disks, the central bulge with the SMBH, the stellar globular clusters, etc.) each for its density, position, kinetic dynamics, etc. will follow a trajectory governed above all by inertia, which, being denser and more compact bodies, will be much more intense than the inertia of the dark structures, which will be more subject to the repulsive forces mentioned above. In these cases, the denser Ordinary Matter components (stars, BH, etc.) can advance quickly against each other, leaving behind the less dense Ordinary Matter, dust and gas, and even more so the dark components. The result of the merger could be a galaxy with a very strange shape, in which the rotation, and especially the dark component, has been lost.
In astronomical observations there are cases of mergers with both outcomes, recognizable despite the almost infinite variability of the modalities, and therefore of the outcomes, in which the collisions and the resulting mergers take place.
In addition to Chirality (which we can see as a sort of "Charge" of the galaxies), the Spin of the two galaxies involved, and their mutual orientation, can also play a significant role in the modalities in which the collision evolves. Spin that does not only represent the spatial orientation of the rotation axis of the galactic bubble in its dark and visible components (mutual arrangement of the galactic disks), but also the source and orientation of the intense galactic magnetic fields.
Dynamics and Interactions
When we talk about dynamics and interaction of galaxies we can / must refer to different observational perspectives. We have a general perspective, the galaxy in its entirety (as here defined, a complex / composite structure, with all its different components, visible and invisible) in dynamical relation / interaction with the surrounding extragalactic environment (a local group, the cluster and supercluster, the cosmos as a whole). We will deal with this aspect in the next section, which focuses mainly on the structures formed by galaxies (groups, clusters, superclusters, filaments, knots, cosmic webs). And we have many different particular perspectives, focused on the single components, on their mutual interactions and on groups of components functionally linked (e.g. the visible Matter bulge, with the stellar objects, the central SMBH, the accretion disk, the possible jets, the central portion of the Dark Halo, and so on).
Let us now mention some of the most significant aspects of the complex dynamics of galaxies, referring however, for any further information, to the sections of the chapter dedicated to the Structures of Information related to the Dark Halos, to Ordinary Matter, etc. and to the previous section of this chapter dedicated to Cosmic objects and bodies.
- Key Dynamical Features of Spiral Galaxies
Spiral galaxies are fascinating structures with intricate dynamics that shape their evolution. Here are some fundamental aspects of their dynamics:
- Rotational motion – Spiral galaxies rotate, with stars and gas moving in nearly circular orbits around the galactic center. The rotation curve of a galaxy—how orbital velocity changes with distance—often suggests the presence of Dark Matter, as outer regions move faster than expected.
- Density waves – Spiral arms are not rigid structures; rather, they are density waves where gas and stars slow down and compress, triggering star formation. This explains why spiral arms are full of young, bright stars. Density waves are the visible effect of the turbulent dynamics of the Dark Matter Halo that constitute the main part of galaxies.
- Galactic differential rotation – The inner parts of the galaxy rotate faster than the outer regions. However, spiral patterns are maintained by interactions between stars and gas rather than simple solid-body rotation.
- Interactions with Dark Matter – The presence of Dark Matter significantly influences the visible galaxy's rotation and stability, preventing stars from dispersing over time.
- Gas flows and star formation – Gas moves through the galaxy, accumulating in spiral arms due to gravitational interactions. This leads to intense bursts of star formation, shaping the visible galaxy’s appearance.
- Central supermassive Black Hole – Many spiral galaxies harbor a supermassive black hole at their centers, which influences dynamics through strong gravitational effects.
Spiral galaxies are incredibly dynamic and change continuously due to these processes.
- Key Dynamical Features of a Elliptical Galaxies
Elliptical galaxies have distinct dynamical properties that set them apart from spiral galaxies. Here are some fundamental aspects of their dynamics:
- Random stellar motion—Unlike spiral galaxies, where stars follow ordered, rotational orbits, elliptical galaxies exhibit random stellar motion in all directions, making them appear smooth and featureless.
- Slow rotation or no disc-like Rotation – Some ellipticals rotate very slowly, while others show no significant large-scale rotation at all. Instead, the stellar movements are governed by velocity dispersion, meaning stars move in various directions rather than in a coherent rotational pattern.
- Dark Matter influence—Just like spirals, elliptical galaxies contain Dark Matter, which plays a crucial role in gravitational interactions and stabilizing the galaxy's structure.
- Lack of star formation—Due to their low gas content, ellipticals rarely produce new stars. Their stellar population consists mainly of older, red giant stars and remnants of past star formation.
- Merging history—Many elliptical galaxies form from galaxy mergers, which disrupt rotational motion and create a more chaotic stellar environment.
- Central supermassive Black Hole effects—The core of most massive elliptical galaxies hosts a supermassive black hole, which can influence surrounding stars and, in some cases, create powerful jets that shape the galaxy's evolution.
Because of their chaotic stellar dynamics, elliptical galaxies evolve differently from spirals.
- Galactic Interactions
Due to the incredible variety of galaxies' structures, shapes, dynamics, turbulent nature, and extragalactic environments, the interactions they can undergo are extremely diverse. Galactic interactions occur when two or more galaxies gravitationally influence each other, resulting in fascinating cosmic events.
Galaxies can also undergo minor interactions, in which a smaller galaxy disturbs the spiral arms of a larger one, or major mergers, in which two galaxies collide and eventually merge into a single entity. Unlike traditional collisions, galactic mergers involve gravitational interactions rather than direct physical impacts.
As seen, among the most important forms of interactions are mergers and collisions, complex events in which galaxies can collide, triggering bursts of star formation and reshaping their structure. These events can reshape galaxies, forming new structures and even activating supermassive black holes. When galaxies interact, their gas clouds can compress, triggering bursts of star formation. Some interactions lead to starburst galaxies, in which new stars form at an accelerated rate.
Galaxies are also in constant interaction with their extragalactic environment. Even without the catastrophic events we have mentioned, they exert a constant gravitational influence. Nearby galaxies exert forces on each other, sometimes forming groups or clusters of galaxies.
Structural and dynamical decomposition in the terms of the Fundamental Physical Quantities of Information / Energy and of the Dynamics of Elementary Action and its Modes / Components
Let's take a step further. Let's try to analyze what has been illustrated above and express it in terms of the models proposed in this work, of the Fundamental Physical Quantities and subsequently of the Dynamics of Elementary Action and its Modes / Components.
This section, although reporting imperfect graphic representations, which in some cases could unfortunately be erroneous (the analyses are still in progress), can be a valid example of how I believe the analysis of objects, Structures, Forms can be conducted with the conceptual tools proposed in the context of this research project. The structural and dynamic decomposition of entities, but also of phenomena, is a key methodology to understand their nature and dynamics in terms of the fundamental and elementary processes that govern the Formation of Reality at all its levels, where the Fundamental Principles of Evolutionary Dynamics are expressed in coherence and stability even if in ever different and changing forms.
Let's assume a well-formed ideal spiral galaxy.
Let us try to graphically represent the radial distributions of the Fundamental Physical Quantities as described in this work (Metric / Mass, Motion, Charge and Spin). Later we will move on to the representation in terms of the Dynamics of Elementary Action and its Modes / Components.
For the sake of simplicity and visual representation, spatial proportions are not always real or correct.
- Metric (correlations of Perturbation of the point events of the Elementary Field)
- Mass (correlations of Perturbation of the point events that are supporting an InfoStructure in the Elementary Field)
- Motion (correlations of Translation of point events that are supporting an InfoStructure in the Elementary Field)
- Potential Motion – Gravitational Potential Energy (combination of Metric and Mass - correlations of Translation of the Elementary Field produced by the correlation of Perturbation that represent Mass of one or more InfoStructures in the Field)
-> IMAGE
- Effective Motion – Velocity (includes the rotational motion of the entire galaxy—in both the dark and ordinary components—don't includes the collective translational motions of the entire galaxy and the translational motions of the substances, bodies, objects and structures that compose it)
-> IMAGE
- Effective Motion – Kinetic Energy (includes the rotational motion of the entire galaxy—in both the dark and ordinary components—don't includes the collective translational motions of the entire galaxy and the translational motions of the substances, bodies, objects and structures that compose it)
-> IMAGE
- Charge – Electric Energy (correlations of Rotation:Chirality of point events that are supporting an InfoStructure in the Elementary Field)
-> IMAGE
- Spin – Magnetic Energy (correlations of Rotation:AxisOrientation of point events that are supporting an InfoStructure in the Elementary Field)
-> IMAGE
In conclusion
Galaxies are very fascinating structures, with various shapes, articulated structures and complex dynamics, in constant evolution.
In short, let's summarize the most characterizing aspects:
- what we can observe through telescopes is not the entire galaxy, but only the part made of Ordinary (visible) Matter capable of emitting electromagnetic radiation,
- the preponderant part of the Mass / Energy and spatial extension of a galaxy is constituted by its Dark structure (Dark Matter and Energy,
- to simplify a lot, a galaxy, especially a spiral galaxy, can be imagined as a gigantic gravitational well, which in spiraling orbits and multiple evolutionary lines tends to carry the galactic and extragalactic materials that enter the galactic bubble towards the central SMBH, where it is compacted and partly redistributed by radiation pressure, polar jets, powerful magnetic fields and gravitational pushes,
- the formation of galaxies is a slow and complex process, much slower than commonly believed. A process through which, extragalactic materials, which are incessantly formed in the friction areas of the dark cosmic web (giant voids, clusters and superclusters Halos, galactic Halos especially in the crowded nodes of the cosmic web, etc.), enter the galactic bubbles and through gravitational, kinetic, chiral and magnetic processes tend to progressively coagulate into objects and celestial bodies, in their incessant and tortuous descent towards the galactic center.