The engine of our universe is the cycle of accretion of gas by gravity until ignition of a fusion reaction, followed by consumption of fuel  until there is an explosion that  recycles gases and  leaves a core that collapses as a black hole. Galaxies are gravitationally stable accretions of matter around a super massive black hole. The structures within the galaxy result from the same underlying dynamic of accretion, ignition, consumption  and explosion anchored around a supermassive black hole.

 

The universe starts a "big bang" that produces with a near uniform distribution of matter. Gravity amplifies the non-uniformity until fusion ignites and huge stars are formed. These stars live a few M years, and then explode creating black holes that proceed to sweep up matter initially as very bright accretion disk around a rapidly growing super massive black hole, called a "Quasar".  Eventually the accretion slows  to form   isolated islands of elliptical and spiral  galaxies in around 1-3 B years. Since then the galaxies are moving  apart as the universe expands, with the occasional merge of local galaxies. A gravitationally stable galaxy includes matter that is 10x larger in diameter than the visible luminous matter. ​​​

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Star Cycle

Stars start with accretion of material around a central mass.  a large gas. The example shows a high-resolution image of a protoplanetary disc   surrounding a star 450 Lyrs away (HL Tauri.) imaged at 1.3 mm wavelength by Atacama Array Telescope. 

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Once gravity compresses the material to overcome repulsion  between atoms, nuclear fusion is ignited. The large UV emission excites any gas around the star and can be seen in many of the nebular in the Milky Way. The example shows the star nursery Rosette Nebula with Hydrogen emissions. 

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Mature stars develop stable emissions the core temperatures that produce black body emissions that our eyes evolved to view. The example shows the corona or our sun during a total eclipse. 

 

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When the Star starts to run out of fuel, it cools to a red color, becoming a "Red Giant".  The example shows the star "Betelgeuse" in Orion which is a Red Supergiant expected supernova within 0.1 M Yrs

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If the star is smaller than 1.4 X our Sun, then the outer layers expand to form colorful nebula such as the "Helix Nebula". Eventually the remaining core becomes a  "White Dwarf" such as the companion to "Sirius". 

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If the star is greater  than 1.4x our Sun, it explodes as a supernova. A recent supernova  SNR 2022   exploded in a galaxy NGC 4647  63 MLyrs from earth. The residues from a supernova explosion in 1054 AD can be seen in the  "Crab Nebula". ​​​

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If the star is less than 4x our Sun, then the remaining core forms  a neutron star that can be seen as a rotating star with a narrow beam of X ray emissions or Pulsar.  M82 or "Cigar" Galaxy in the  Bode Group has a neutron star as X ray pulsar at its center.​​​

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If the star is greater than 4x our Sun, the remaining core forms a black hole. 

As noted above  a Supermassive Black hole has been  imaged  in M87 which is associated with the  Markarian Chain  of galaxies. 

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​The different nebulae, white dwarfs, neutron stars are all recycled by accretion around a new proto-star mass. This completes the star cycle. 

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The black holes go on to form the anchor for collections  of stars. A "Super Massive Black Hole with 10^6 solar masses anchors whole galaxies.​

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Evolution of Galaxies 

​The evolution of galaxies starts with the Big Bang, followed by first stars that collapse into black holes, which then accumulate mass while radiating energy, eventually so many stars  mass assemble around the black hole that it becomes a gravitationally stable island we identify as a galaxy with quiescent black hole at its center. 

 

The universe starts with a Big Bang.  The "inflation era" covers the time from initiation, to the flash of light from the bang.  The inflation model suggests that at the beginning of the big bang a patch matter (smaller than the size of a proton) underwent a phase transition bringing about a huge gravitational repulsion. This is the driving force behind the space-explosion that was the big bang.  ​​The phenomenon of particle creation in an expanding universe  is associated with the appearance and disappearance of particle–antiparticle pairs in the vacuum. Such energy non-conserving processes are permitted as long as they take place on a sufficiently short timescale  However, when the space is rapidly expanding, that is, the expansion rate was larger than the annihilation rate, real particles were created. This hot, dense, uniform collection of particles is  the postulated initial state of the standard big bang model.  The epoch when charged nuclear ions and electrons were transformed into neutral atoms is called the photon-decoupling time. This took place when  the thermal energy of photons just dropped below the threshold required to ionize the newly formed atoms. The redshifted light from the big bang, is seen in the Cosmic Microwave Background. Because of gravitational instability, this nonuniform distribution of matter in the CMB eventually evolved into the stars and galaxies  we see today.

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The CMB shows nonuniformities in mass, that get amplified by gravity, eventually the material is compressed to the point of ignition of fusion. These stars appear after 200-250 M years. They are massive at 200-300 solar masses and short lived around 1 M years. They explode in supernova and collapse into a black hole. The Tarantula Nebula in the LMC, contains 9 stars >150 solar masses. 

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These black holes act as gravity sinks that then control the evolution of galaxies. Material around the black "accretes" or falls towards the black hole due to gravity. The black hole increases in size, causing a further increase in gravitational pull. These can grow to over 10^6 solar masses as "Super Massive Black Holes" (SMBH). The material falling into the SMBH gets close to light speed and emits very intense radiation. These objects are called "Quasars". ​ A survey of quasars found 100,000's distributed across the universe not obscured by the  Milky Way. These highly radiant objects are "Quasars". ​​​The Chandra X-ray image is of the quasar PKS 1127-145, a highly luminous source of X-rays and visible light about 10 billion light-years from Earth

​https://iopscience.iop.org/article/10.3847/1538-4357/ad1328

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The SMBH continues to attract stars and gas, As this material accumulates, the gravitation pull close to the SMBH is reduced. When the surrounding material gets to be 1M time larger than than the SMBH, the SMBH stops growing and becomes quiescent.  The combined SMBH and surrounding matter form a gravitationally stable island. The SMBH can still be seen in radio wave emissions at 1.3mm wavelength. ​ A stable  galaxy forms when the external mass balances the black hole at the center.  For example Milky Way has a mass of 10^12 solar masses, with a SMBH of 10^6 solar masses at it's core - 1 Million times more mass surrounds the SMBH. 

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If the island does not rotate, the stars form a uniform spheroid around the SMBH, with very little new star formation - as seen in M60.​

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If the material around SMBH is rotating,  the stars form spiral arms. Within the arms, gravity forces matter to further accumulate, ignite and form new stars. These regions can be seen in red nebula of emissions from excited Hydrogen.  M81 or Bode Galaxy  is a good example.  The angle of the spiral depends on the size of the SMBH. The SMBH have been visualized in the Milky Way, and Messier 87 part of the Markarian's Chain. The SMBH is cold with very little accretion that only emits radio waves.  The Event Horizon Telescope (EHT)  began observing the black hole at the centre of Messier 87.[155][156] "In all, eight radio observatories imaging at 1.3mm on six mountains and four continents observed the galaxy in Virgo on and off for 10 days in April 2017" to provide the data yielding the image in April 2019. ​

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Most bright galaxies have remained fundamentally unchanged for  billions years, and the net rate of star formation probably peaked about 3 B yrs after Big Bang.  At this point, accretion has ended and galaxies are stand alone entities and the universe can expand without gravitational resistance.

https://en.wikipedia.org/wiki/Galaxy

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There is  an average density of 1 galaxy per 20 MLyr diameter spherical volume. At the speed of light the minimum time for the Black Hole  to deplete out to the edge  of its volume of influence would be 10M yrs.

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​​Most of todays galaxies are the result of 2-3 merges. Each merge results in a reorganization depending on the orientation of the merging galaxies. 

 Whirlpool Galaxy is an example of a merge  of a spiral with a smaller galaxy that appears to be feeding the spiral arms.

https://www.sciencenews.org/article/water-circling-drain-provides-insight-black-holes & https://www.nature.com/articles/nphys4151

​​​​https://news.mit.edu/2022/early-universe-model-0324

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Milky Way luminous edge diameter = 0.1M Lyr

Dark matter edge 10x larger; diameter = 1.2 MLyr

On average there is 1 galaxy  per sphere volume  20 MLyr diameter. 

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Leo Triplet - 10 Mlyr apart, 40 Myr away.

Stephans quintet Higsen Group = 30 Mlyr apart, each 0.1 Mlyr across, 300 Mlyr away.  

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​Universe starts at 10^5 M0 per MLyr3. Concentrates to 10^12 M0 in a 1 Myr cube in black hole. or  10^7  times concentration. ​

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Within the local group diameter 2M Lyr  there is sufficient gravitational attraction to  result in merging of the Milky Way, LMC and Andromeda.  Andromeda is thought to have seen a merge with a 1/4 sized galaxy around 4 billion years ago. The Milky way will merge with Andromeda Galaxy in 4.5B yrs.

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local group - 2 Mlyr apart, each 0.1-0.2 Mlyr across, 2Mlyr away.

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Universe doubling every 20B years.

 

​The universe is expanding based on evidence that the redshifts of older galaxies are larger proving  that the further away or older the galaxy the faster it is moving away. There is a subtle non linearity which if maintained in the future is evidence that the expansion is accelerating.  

https://image1.slideserve.com/1756061/is-the-expansion-of-the-universe-accelerating-l.jpg

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An alternative explanation is that the red shift of the oldest galaxy results from DEACCELERATION from explosive early expansion,  caused by gravitational attraction of galaxies before they become isolated. If so the expansion will be constant in the future with no need for dark energy !

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​Metrics 

First star Mass          3.00E+02M0

Life                              1Mlyr

Mass of Universe      1.00E+23M0

Mass of MWay           1.00E+12M0

Number of Galaxies 1.00E+11M0

Observable  diameter 9.30E+10Lyr

Volume                           4.21E+32Lyr3           =4/3*3.142*r^3

Volume per galaxy       4.21E+21Lyr3

Volume radius              1.10E+07Lyr              Diameter 20M Lyr

Before accretion         2.37E-10 M0 per Lyr3  2.37E+08M0 per  MLyr

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Our sun is expected to live for 10 B years - or the current age of universe, so about half the visible stars are probably on their first life cycle. 

lifespan of the star = lifespan of the sun * (star mass / solar mass) -2.5.  

https://rechneronline.de/planets/lifespan-star.php#google_vignette

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Crab Nebula  in Orion

Helix Nebula   Sept-Oct

Betelguse  in Orion  Sept- Oct

M66 in Leo Triplet  in Leo , Mar

NGC1300 in Eridanus Cluster in Orion Nov-Dec 

Markarians  Chain  in Leo Apr-May

Sephans Quintet in Deneb Oct-Sept

Seyfert's Sextet  190 MLyr  1' diameter in Bootes  Apr-May 

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Quantitative cosmology  

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3 critical pieces of hard data;​

• Receding Galaxies - confirms Big Bang

• Rotation of Galaxies 

• Cosmic Microwave Background - confirms Big Bang 

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Receding galaxies

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The observable universe is limited to stars that are close enough that photons travelling at the speed of light can get here, illustrated by the light triangle in the sketch. Hubble telescope enabled the observation of much dimmer objects, James Webb telescope sees even dimmer and colder objects in the IR. The Plank telescope sees the CMB in the deep IR at a wavelength of 10,000 um. These telescopes have transformed our understanding of the Universe, with images of orders of magnitude more galaxies and the CMB. 

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Universe is doubling in size every 20B years.

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The first quantitative insight into the evolution of the universe came from Hubble in the 1920's when he showed that mores distant galaxies were moving away quicker. This proved that the universe is expanding and must have started in a Big Bang.

 H0 = (72 ± 7 km/s)Mpc−1 , (7.7) where the subscript 0 stands for the present epoch H0 ≡ H(t0). An inspection of the Hubble’s law (7.6) shows that H0 has the dimension of inverse time, and the measured value in (7.7) can be translated into Hubble time tH ≡ H −1 0 ≃ 13.6 Gyr and Hubble length lH = ctH ≃ 4,200 Mpc

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The classic display of raw galaxy data is Luminosity of 1a supernova as a proxy for Distance vs. Redshift as a proxy for velocity. The accelerating universe is indicated by distant (old) galaxies that have less red shift than linear extrapolation. The review by Riess in 2000 showed the original Reiss and Permutter publications. There is enough noise in the raw data to question any non linear hypothesis. The authors used correlations to parametrized Cosmological Constant to extract the signal from the noise, and claim an ACCELERATING  expanding universe and support for dark energy.

Relativity, Gravitation, and Cosmology A basic introduction TA-PEI CHENG

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Rotation of galaxies

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Spiral galaxies are rotating at at roughly  uniform angular rate, just like a frisbee, consistent with a  long term stable structure. 

 

The latest images from  the Webb Telescope show increased IR luminosity out at the edge of the galaxies.  Other data includes; the angle of the spirals is related to the size of the black hole at the center of galaxies (Seigar). 

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The simplest possible model based on Newtonian gravity where the gravitational effect of a distributed sphere can be approximated by a point source at the center. It predicts that the rotation speed should drop as the square of the 1/ radius and that the galaxy will fall apart in a few rotations. 

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          GMm/r^2=mV^2/r   so V=(GM/r)^0.5

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Thus the tangential velocity inside a galaxy is expected to rise linearly with the distance from the center v ∼ r if the mass density is approximately constant. For a light source located outside the galactic mass distribution the velocity is expected to decrease as v ∼ 1/ √ r. If gravity is linear with radius, then V would be constant.

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Comprehensive studies of the rotation of galaxies includes data from CO emissions, optical spectroscopy and microwave studies of H1 emissions. The visible edge of galaxies is typically around radius of  10-20 kparsecs, and direct rotation measurements have been made out to 30 kparsecs.  Andromeda M31 has been studies using interactions with other galaxies in the Local Group, velocity curves out to 200 kparsecs = 600 kLyrs. 

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GRAVITY OF DISTRIBUTED MASS OBJECTS 

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Sofue has used the velocity curves to calculate what the mass distribution must look like. The results for multiple galaxies show a simple exponentially declining surface mass density (SMD)  out to 300-500 kparsecs. There is no sign of a new structure. 

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They also decomposed the mass distribution into gaussian components. In their decomposition, the dark matter halo is roughly 10-20x the mass of the luminous matter because even though it is very dilute, it is spread over a large area.  

 

Matter made up of protons and neutrons is generally referred to as “baryonic matter.” As it turns out, we have methods that can distinguish between baryonic and exotic dark matter because of their different interactions. The light nuclear elements (helium, deuterium, etc.) were produced predominantly in the early universe at the cosmic time O(102 s), cf. Section 8.4. Their abundance (in particular deuterium) is sensitive to the baryonic abundance. From such considerations we have the result (Burles et al., 2001) .

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        Baryonic Dark  Matter Fraction = 4%,

        Luminous Matter Fraction = 0.5%

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A plot of Mass/Luminosity against radius, suggests that the outer galaxy contains progressively more dark matter.  It seems likely that the dark halo is in fact "Baryonic dark matter" such as gas and star remnants. This is consistent with other estimates of Baryonic Dark Matter as discussed below.

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Cosmic Microwave Background CMB

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The discovery of the CMB was the second key evidence that the universe started with a big bang. A series of satellites have made detailed measurements. After removing the shadows caste by the Milky Way, the CMB looks uniform across the sky with local non-uniformities. 

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A 2D Fourier Transform gives the power spectrum of the non - uniformities or "anisotropy" of the CMB. The multiple frequencies in the power spectrum has been taken as evidence supporting the "Inflation" model of the pre CMB universe.  The inflation model also proposes a flat universe,

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The CMB power spectrum monopole frequency. In a flat universe we expect the frequency of the monopole to be 200. The angular non-uniformity  in temperature fluctuations reflect the sound wave spectrum of the photon–baryon fluid at photon decoupling time.  However, the fits to the power spectrum do not allow unique values for flatness and mass known as "degeneracy". 

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Lamda CDM model

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The  Hubble plot and CMB power spectrum form 2 independent data sets of different metrics for 2 different era's and are  the  perfect basis for a complete model of the universe. 

 

Todays  "standard model" of the universe is "Lambda CDM". The model is based on the "Friedman Equations" derived from General Relativity. The mass -  energy balance and the shape of the universe are critical.

 

The inflation model suggests that the universe is flat. IF this is correct, the Hubble Constant gives a value for all the mass in the universe - "critical mass". We can total all the mass that we know about, luminous mass and baryonic dark matter and we get roughly 4% of the critical mass. The difference between known mass and critical mass must be undiscovered "dark" and can be energy or mass.  

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The independent fits to Hubble and CMB data cannot discriminate  dark  energy and  matter. The best simultaneous fit relies on 2 adjustable parameters "dark matter" at 27% of the total mass, and "dark energy" at 68% of the total energy of the universe. The presence of dark energy would imply that the expansion of the universe is accelerating, and requires the Cosmological Constant 'Lambda" in General Relativity. The "Cold Dark Matter" (CDM),  explains the expansion of the early universe. 

 

To date there is no quantitative theoretical rationale or direct experimental observation of either dark matter or dark energy. Futhermore, as quality of observations has improved the estimate of Hubble constant from applying Lamda CDM model to CMB is now statistically significantly different from the measured Hubble constant from galaxy motion - even after invoking dark matter and dark energy.

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IF the universe follows General Relativity without the Cosmological Constant, then the universe is open (never closes) and negatively curved.

There is no need for dark energy or dark matter, BUT there is no model parameters that fit Hubble and CMB simultaneously. 

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Further evidence that challenges dark energy "Professor Subir Sarkar from the Rudolf Peierls Centre for Theoretical Physics, Oxford along with collaborators at the Institut d'Astrophysique, Paris and the Niels Bohr Institute, Copenhagen have used observations of 740 Type Ia supernovae to show that this acceleration is a relatively local effect—it is directed along the direction we seem to be moving with respect to the cosmic microwave background (which exhibits a similar dipole anisotropy). While the physical reason for this acceleration is unknown, it cannot be ascribed to dark energy which would have caused equal acceleration in all directions."

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"Thus the cosmic acceleration deduced from supernovae may be an artefact of our being non-Copernican observers, rather than evidence for a dominant component of “dark energy” in the Universe." In summary, the model-independent evidence for acceleration of the Hubble expansion rate from the largest public catalogue of SNe Ia is only 1.4σ. This is in contrast to the claim (Scolnic et al. 2018) that acceleration is established by SNe Ia at >6σ in the framework of the ΛCDM model.

Jacques Colin et al. Evidence for anisotropy of cosmic acceleration, Astronomy & Astrophysics (2019). DOI: 10.1051/0004-6361/201936373

https://asgardia.space/en/news/Scientists-Claiming-Dark-Energy-Doesnt-Exist-Unwilling-to-Reconsider

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Still many unsolved problems Although we have a self-consistent cosmological description, many mysteries remain. We do not really know what makes up the bulk of the dark matter, even though there are plausible candidates as predicted by some yet-to-be-proven particle physics theories. The most important energy component is the mysterious “dark energy,” although a natural candidate is the quantum vacuum-energy. Such an identification leads to an estimate of its size that is completely off the mark (cf. Section A.4). If one can show that the quantum vacuum-energy must somehow vanish due to some yet-to-be-found symmetry principle, a particular pressing problem is to find out whether this dark energy is time-independent, as is the case of the cosmological constant, or is it more like an effective Lambda coming from some quintessence scalar field like the case of inflation.

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