# 'Dark Matter' & 'Dark Energy' are real, normal

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'Dark Matter' & 'Dark Energy' are real, and entirely normal [DRAFT]

'Dark Matter' (DM) & 'Dark Energy' (DE) are known to have different properties, i.e. "behave differently". DM is spatially associated with stars in galaxies, which stars "trace" the presence of DM; and, DM possesses properties similar to stars, i.e. slow-moving, massive, gravitating point-particles. Prima facie, DM is dim stars, e.g. brown dwarves; and, dim stellar remnants, e.g. white dwarves, neutron stars, black holes. By contrast, DE is a uniformly distributed, diffuse, matter-and-energy density, logically linked to the vast inter-galactic 'Voids', which encompass most (~3/4ths) of the space in our universe. Prima facie, DE is diffuse inter-galactic gas, i.e. inter-galactic medium (IGM).

Cosmic Web resembles closed space-time fabric, with "kinks & creases"

If our universe is uniform, i.e. "the (exact) same every-where"; and, has a "closed" global curvature; then, our space-time fabric is "hyper-spherical" -- i.e. "slices" of our space-time fabric, representing the same time, for every-where throughout space, would be hyper-spheres. Such a hyper-spherically curved-and-closed space-time fabric can be (partially) visualized, via a "(2+0)D in 3D" projection -- which omits one spatial dimension; and, the time dimension -- as a "sphere-land" (cp. "flatland" visualizing a "flat" space-time fabric):

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The above visualization is valid, only for a mathematically-idealized uniform universe, throughout which matter-and-energy is distributed perfectly evenly. But, our actual universe is not homogeneous. Instead, our actual universe is "clumpy" -- i.e. matter-and-energy is distributed un-evenly, with slightly more matter-and-energy in some regions; and, slightly less matter-and-energy in other regions.

Recall, that General Relativity, is an entirely "local" theory (Wheeler. Journey into Gravity & Spacetime):

• matter "here" tells space-time "here" how to curve
• curved space-time "here" tells matter "here" how to move

Therefore, if, in an initially-uniform universe, matter-and-energy were caused to "clump"; then, the initially-smooth "spherical" space-time fabric would "kink", in response to the new-and-now-non-uniform matter-and-energy distribution -- i.e. the "new instructions", input into the space-time fabric, from the newly re-distributed matter, inside that space-time fabric. Qualitatively, "sphere-land" would, there-from, become "poly-hedron-land" -- i.e. approximately smooth-and-spherical, globally (on "large" size scales, bigger than the "clumps"); but, "kinked", locally (on the "small" size scales, of the "clumps"). By analogy, circles can be approximated with poly-gons:

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Qualitatively, the "lattice-work", of the "kinks", in the space-time fabric, of "poly-hedron-land", resembles the "web-work", of the Large Scale Structure (LSS), in our cosmos, i.e. the Cosmic Web (CW):

• vertices <---> Clusters
• ...edges <---> Filaments
• ....faces <---> Voids

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Qualitatively, the fabric of space-time is "robust" -- i.e. the global geometry, i.e. topological "shape", of a space-time fabric, on "large" size scales, is not radically altered, by localized re-distributions of matter-and-energy, on "small" size scales.

our universe is filled with "two phase" medium, i.e. 'Voids' & 'Structures'

From the remote universe, at a red-shift of z~1000, the Cosmic Microwave Background (CMB) is observed to be nearly perfectly uniform, i.e. "the same from all directions". However, the CMB evidences "weak" variations, with a maximum relative amplitude of ~10-5, at angular size scales, of ~0.7 degrees (UCLA). Such variations correspond, at present epoch (z=0), to a current co-moving spatial size scale, of ~100 Mpc (Caltech). Recall, the space-time fabric, of our universe, is expanding; and, has expanded, by a factor, of ~1000x, since the archaic epoch (z ~ 1000), corresponding to the CMB. Thus, the variations, seen in the CMB, were "then", i.e. at that archaic epoch, ~1000x smaller, in spatial size, i.e. ~100 Kpc.

Meanwhile, in the local universe, at red-shifts z < 0.2, luminous matter is structured, at the same spatial size scale, of ~100 Mpc, characteristic of LSS, i.e. the CW (Landy 1995, Scientific American). And, such "large" structures are so big, that they cannot have formed, from the "peculiar" motions of matter-and-energy through our universe (v < 0.001 c), during the age of our universe (t ~ 10 Gyr, i.e. vt < 10 Mly << 100 Mpc) (Daily Galaxy). Thus, such "large" structures must have already been formed, by the Big Bang, i.e. they must be "primordial" structures.

Recall, "weak" variations, of order ~10-5, seen in the CMB, reflect comparably "weak" variations, in the distribution, of matter-and-energy, in our universe, at that archaic epoch (z ~ 1000). Application, of linear perturbation theory, to the equations, from General Relativity, for our expanding space-time fabric, predicts that such "weak" variations, in the distribution of matter-and-energy, at that archaic epoch (z ~ 1000), will have amplified, by ~1000x, by present epoch (z=0) (Carroll & Ostlie. Introduction to Modern Astrophysics). Therefore, variations in the distribution, of matter-and-energy, in our universe, at present epoch, are predicted to be of order ~10-2, i.e. ~1%.

Thus:

• CMB variations "there & then" correlate to LSS "here & now"
• CMB variations, which were "there & then" ~100 Kpc in spatial-size, have evolved into LSS structures "here & now" ~100 Mpc in spatial-size -- i.e. CMB structures have stretched ~1000x with expanding space-time
• "weak" CMB structures, which were "there & then" ~10-5, are predicted to have "strengthened" to be ~10-2 "here & now"

So, "weak" variations, in the primordial distribution of matter-and-energy, in our universe, are predicted to have "passively" been stretched, by expanding space-time; and, to have "strengthened" into the LSS, i.e. CW, observed at present epoch; but, to represent merely "minor ripples" ~1% on an otherwise nearly uniform matter-and-energy distribution, at present epoch.

These predictions are completely consistent, with observations, of the CW, i.e. the relative masses & volumes, of 'structure' vs. 'voids' (CR4):

• 'structure' = 24% volume, 26% matter-and-energy (luminous matter + 'Dark Matter')
• .....'voids' = 76% volume, 74% matter-and-energy ('Dark Energy')

However, these predictions are completely in-consistent, with current cosmological computer simulations, which generate 'structure' that is prominent & pronounced, characterized by density contrasts, as compared to simulated 'voids', of order 1 -- i.e. ~100x greater in magnitude, than observed, in our actual universe. Such simulated 'voids' are nearly completely evacuated, of simulated matter, nearly all of which is accreted, onto simulated 'structures', by simulated present epoch (z=0). But, actual 'voids', in our actual universe, retain nearly all of their primordial matter-and-energy, with only ~1% having accreted, onto actual 'structures', by present epoch. I.e. in simulations, 'voids' are "deeply dredged"; whereas, in our actual universe, 'voids' are observed to have been only "superficially skimmed".

Therefore, despite the "optical prominence" of the CW, such LSS represents an as-yet-weak perturbation ~1%, in an as-yet-nearly homogeneous matter-and-energy distribution, in our universe. Compared to current cosmological computer simulations, which seek to "cram" all matter, into shapes similar to observed "optically prominent" LSS, the actual CW, in our actual universe, represents an as-yet-weak "clumping", of the ambient Inter-Galactic Medium (IGM). I.e. in simulations, 'structures' are "major waves"; whereas, in our actual universe, 'structures' are observed to be only "minor ripples".

Yet, those "minor ripples" differentiate diffuse IGM, i.e. 'voids', from compact galaxies of stars, i.e. 'structures'. By analogy, the difference between dynamically-young, diffuse, "warm", primordial plasma, in 'voids'; and, dynamically-evolved, compact, galaxies of stars, in 'structures', resembles a "phase change at (nearly) constant density":

Observations of the IGM indicate characteristic temperatures of ~104 K (Scientific American, Space), with "weak clumping" into IG "clouds" (Discovery). If the "warm" IGM is dubbed the "Warm Intergalactic Medium" (WIM); and, if that "warm" IGM accounts for the 'Dark Energy' density; then, that "warm" IGM could be called the "dim WIM", implicitly presuming the eventual observability, of the ultra-low-surface-brightness, ultra-faint, IGM.

Edited by Widdekind

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"Dark Debris" of primordial star-formation [DRAFT]

CMB

CW
= Cosmic Web

DE
= Dark Energy

DM
= Dark Matter

HII
= ionized hydrogen region

LSS
= Large-Scale Structures

WIM
= 'warm intergalactic medium' (ultra-vast HII regions)

'DM' = dim stars, 'DE' = dim WIM

'DM' and 'DE' resemble two 'phases', of a single 'dark fluid', such that "on the scale of galaxies, this 'dark fluid' behaves like '[dark] matter'; and, on the scale of the universe overall, as 'dark energy'" (Science Daily 2008). That resemblance is consistent, with 'DM' and 'DE' both being normal 'baryonic' matter, i.e. primordial H & He gas; but, which has either gravitationally collapsed, into compact stars, of low luminosity, e.g. brown dwarves, in the halos of galaxies ('DM' = 'dim stars' in 'Structures'); or, which has remained a diffuse & uniform gas, in between those galaxies, and which was presumably "warmed" to temperatures ~10,000K, during 'Reionization', i.e. by early stars in those then-active galaxies ('DE' = 'dim WIM' in 'Voids').

Indeed, 'DM' traces normal luminous matter, e.g. stars, in observations of galaxies (Science Daily 2009, Nature 2009); and, in computer simulations, of clusters of galaxies (Science Daily 2011). Therefore, 'DM' is strongly associated with big-and-bright stars, suggesting that 'DM' is small-and-dim stars.

Meanwhile, 'DE' accounts for ~3/4ths of the over-all matter-and-energy density, in our universe, i.e. over "large" spatial size scales, at which our universe is (statistically) uniform. And, deep inter-galactic 'Voids' account for ~3/4ths of the over-all volume, of space, in our universe. Therefore, 'DE' can be parsimoniously attributed to 'Voids'. And, there-with-in, the diffuse-and-dim character, of 'DE', can be parsimoniously attributed to diffuse-and-dim inter-galactic gas. If so, then 'DE' is warm inter-galactic medium, i.e. 'dim WIM'.

'Structure' = star-forming filaments, 'Voids' = dispersed HII

The interiors, of star-forming molecular clouds in galaxies, are a web-work of filamentary "clumps" (Chandra 2006). For example, the interior, of a molecular cloud, in our neighboring 'LMC', has been revealed, by the explosive expansion, of an adjacent 'SNR':

N49: Stellar Debris in the Large Magellanic Cloud

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Furthermore, after star-forming clouds condense, into nascent "nests" of stars; and, after the "parent" clouds are dispersed, by the radiation & winds, flowing from those "newborn" stars; those stars are observed to have formed in filamentary "streams" & "chains", e.g. Ursa Major Stream through which our star-system is presently passing (Inglis. Astrophysics is Easy, p.76,83). Prima facie, filamentary structures in star-forming clouds, in galaxies, resemble the filamentary 'LSS' of the 'CW', in our universe. Similarly, the ionization & dispersal of cloud material, by the stars, in the filaments of clouds, resembles the 'Reionization' of the IGM, by the stars & galaxies, in the filaments of the CW:

• ................................star-forming cloud (GMC) <---> pan-cosmic medium (IGM)
• intra-cloud filaments of stars (chains, streams) <---> filaments of galaxies (LSS, CW)
• cloud material dispersed by stars (HII regions) <---> primordial plasma heated during 'Reionization' (Voids)

If so, then 'Voids' in our universe represent regions which were 'Reionized', by the first stars in early galactic 'proto-Structures', before the formation of stars or galaxies could locally proceed to completion.

The gas-to-stars conversion efficiency, in modern star-forming clouds, is ~10%, i.e. ~90% of cloud material is dispersed. By comparison, the gas-to-structure conversion efficiency, in our early universe, was ~25%, i.e. ~75% of the pan-cosmic medium was dispersed. Thus, the comparatively high matter conversion efficiency, during the formation of 'Structures' in our universe, suggests that primordial star-formation generated relatively more low-mass, low-luminosity stars, i.e. small-and-dim stars comprising 'DM'.

CMB variations "there-and-then" = CW LSS "here-and-now"

Variations detected, in the CMB, from the far-away-and-early universe (z~1000), correlate to structures detected, in the distribution of galaxies, in the nearby-and-modern universe (z~0) (Science Daily 2011).

Edited by Widdekind

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'DM' = 'brown dwarves' ?

Red halos of galaxies – Reservoirs of baryonic dark matter?

Deep optical/near-IR surface photometry of galaxies outside the Local Group have revealed faint and very red halos around objects as diverse as disk galaxies and star-bursting dwarf galaxies. The colours of these structures are too extreme to be reconciled with stellar populations similar to those seen in the stellar halos of the Milky Way or M31, and alternative explanations like dust reddening, high metallicities or nebular emission are also disfavoured. A stellar population obeying an extremely bottom-heavy initial mass function (IMF), is on the other hand consistent with all available data. Because of its high mass-to-light ratio, such a population would effectively behave as baryonic dark matter and could account for some of the baryons still missing in the low-redshift Universe. Here, we give an overview of current red halo detections, alternative explanations for the origin of the red colours and ongoing searches for red halos around types of galaxies for which this phenomenon has not yet been reported. A number of potential tests of the bottom-heavy IMF hypothesis are also discussed.

'DE' = diffuse IGM ?

'Dark Clouds' of H, in IG space, that emit no radiation; and, could represent dejected debris, from galaxies; or, dynamically-young, slowly-forming, still-proto-galaxies. Normal 'baryons' still have "room to ride" -- if allowed to do so -- to explain observed 'DM' & 'DE'.

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'normal matter' explanation, for 'DM' & 'DE', explains 'suspicious similarity' paradox

'DE' is inferred to exist, diffusely, in deep inter-galactic space, i.e. 'Voids', without collapsing into galaxies & galaxy groupings, i.e. 'Structures' of 'Cosmic Web'. Thus, 'DE' possess the properties, of warm diffuse IGM. And, 'DE' density is comparable to 'DM' density. Thus, 'DE' & 'DM' possess the properties, of normal matter, in observed star-forming clouds, where-with-in vaguely similar amounts of material are 'dispersed' back into space (i.e. 'DE' = dim IGM) vs. 'condensed' into stars (i.e. 'DM' = dim stars):

CMB observations [indicate] that space is indeed very close to flat. But, luminous & 'dark' matter combined provide only 30% of the energy density required to make the universe flat. There must be some additional energy component, that doesn't allow itself to be gathered into galaxies, or galaxy clusters... We have detected 'dark' matter indirectly, by seeing its gravitational influences [because] matter settles into galaxies & clusters, where we can see its gravitational effects concentrated in one region. [There could be] some form of perfectly smooth energy that doesn't concentrate into dense regions...

'dark energy' density is suspiciously close to that of matter... the present densities, of 'dark energy' & 'dark matter' are comparable, within a factor of 3 (Sky & Telescope)

sight-lines, from earth (center) to CMB emission regions (rim) thread through 'Voids' & 'Structure' in
~3:1
ratio, potentially explaining 'DE':'DM' ratio

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'DM' is associated solely with 'Structures', i.e. 'CW'; and, is absent from 'Voids', which contain only 'DE' (universe today). This 'DM = dim stars, DE = dim IGM' hypothesis can account, naturally, for such observations.

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(1) CMB reflects "sound waves" in early pan-cosmic plasma

As the newborn universe expanded, matter and energy seethed within a dense cosmic broth. Tiny fluctuations in this broth...resulted in some regions having more matter than the rest...

they rebounded and then oscillated, sending sound waves reverberating through space. Today, the stretched-out remnants of these waves still pervade the universe as subtle ripples in a faint glow called the cosmic microwave background. Theorists predicted that galaxies would tend to be found on the peaks of these ripples, just as water tends to pile up in ripples spreading on a pond [and] galaxies have a characteristic separation of 500 million light-years (science 2005)

(2) "sound waves" in space plasmas generate "turbulence"

On earth, the self-similar structures in smoke plumes and atmospheric clouds are the result of turbulence. Turbulent motions produce hierarchical structures because the large-scale parts of the motion produce the large-scale concentrations, and the small-scale parts of the motion produce the small-scale concentrations.

Many people think of turbulence as the random jittery motions that toss airplanes around in an unpredictable fashion. But there is also a regular and systematic element to turbulence: Nearby regions tend to move at about the same speed, whereas distant regions move more independently. Very simply, the greater the separation between two fluid elements, the greater the difference in their relative velocities.

Most earth-bound turbulence has a pattern of velocities that increases as the cube root of the separation. This pattern appears to be generally true for incompressible fluids, and for disturbances in air that are at such low pressures that the density remains fairly constant. The relation is a little steeper for astronomical turbulence, with velocity scaling approximately as the square root of the separation. The difference may be the result of larger pressure fluctuations for astronomical turbulence. These fluctuations tend to be so large in space that they actually compress the gas, forming density enhancements. These are presumably the same density enhancements that make newborn star clusters (American Scientist 1998).

Inter-stellar turbulence
(yellow arrows) produces clouds because the pressure fluctuations are so strong that they compress the gas, forming regions of enhanced density, which ultimately condense to make stars. Large-scale turbulence produces the large-scale structures at high speeds, and small-scale turbulence produces small structures at low speeds, yet the nature of the gas motions is the same on large and small scales in these turbulent regions. That is, the relation between the highest velocities and the lowest velocities is similar at each level. This scale-free distribution of velocities produces a fractal distribution of clouds and stars.

Linda Huff

(3) "primordial turbulence" generated first stars, i.e. Pop. III ??

Could the sound waves, seen in the CMB, have been associated with turbulence, or even turbulence-triggered star formation ??

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The star-formation efficiency, of star-forming clouds, in the disk, of our galaxy, is 25% (Sky & Telescope 1998), i.e. "cosmologically exactly" that required by this "dark matter-and-energy is dim stars-and-gas" hypothesis.

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"Bottom heavy" star-formation may occur, in the cores, of clusters of galaxies, whose ICM are under-going "cooling flow" collapse, where "low mass stars are favoured over higher mass stars; the upper limit of the stellar mass of cooling flow-generated stars seems to be in the range of 1 - 2.5 solar masses" (irwin).

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Galaxy clusters are thought to be a statistically representative sample, of our cosmos' contents. And, in clusters, "the total mass of the intra-cluster medium [iCM] is about one tenth of the total cluster mass, and about 6 times that of all the stars in the member galaxies" (Fabian 2003).

Now, human astronomers assume, that:

$\frac{\Omega_b}{\Omega_M} \equiv \frac{M_{gas}}{M_T} + \frac{M_{gal}}{M_T} = f_{gas} + f_{gal} \approx 1.16 f_{gas}$

where Mgas measures the observed amount, of x-ray luminous ICM; and, Mgal measures the observed amount, of visibly luminous stars, i.e. without including galaxies' 'DM' halos; and, MT adds, to the above, the inferred amount of 'DM'. And, the value, of the ratio, is calculated to be about 1:7, with fgas = 0.11, fgal = 0.02 (Allen 2002).

Please ponder, that if galaxy 'DM' halos are 'dim stars'; and if those 'dim matter' halos are included in cluster galaxy masses, i.e. fgal = 0.9; then fgas + fgal = 1, i.e. $\Omega_b = \Omega_M$. Thus, cluster observations are consistent, with the "common-sense cosmology". Only the assumption, that 'DM' cannot be baryonic, due to the demand, of theoretical primordial nucleo-synthesis calculations, "flies in the face" of a "common-sense cosmology", i.e. "all-and-only matter".

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