Relativity describe the properties of Black Holes but also suggest the existence of a second associated object called a White Hole. Theorising about possible candidates may help us to understand Galaxy evolution.
The enlargement of galaxies is generally accepted to be through merger, called the Standard Model, where they coalesce by gravitational attraction. This fails to explain the association between Galaxies and the Super Massive Black Hole (SMBH) lurking in the centre.

SMBH/Galaxy association.

The connection between galaxies and their SMBH:

1 There is a correlation in size as the SMBH is about 0.5% the mass of the Galaxy suggesting they increase or evolve together.

2 There only appear to be one and right in the centre.

3 The plane on which the galaxy forms respects the SMBH’s magnetic field - if it jets (presumably from the poles) that is at 90° to the galactic plane as a recognition of its equator. 

4 The entire galaxy rotates or orbits about this SMBH like a vast disc. 

5 This object is unusually large, at least 1000 times bigger than anything else, suggesting a special evolutionary path.

                                               Sgr A - Galactic centre in the x-ray.

SMBH Galaxy Core 

Some estimation of the properties of such a massive object in such a matter rich environment can be guest. There are Black Holes (BH) of this size or bigger elsewhere that are the brightest objects in the Universe called quasars. That description will not fit Sgr A galaxy core which should be bright in the x-ray, flare as stars are pulled in and have a large accretion disc which it does not. It appears discreet, dull and mysterious. Quasars and SMBH are not at all comparable.

The rotation speed has been unusually difficult to calculate suggesting strange characteristics.

We can be confident its a BH as there is no other object it could be - which is not true. Part of the prediction concerning BH (in Relativity) is also describes a second and associated object. Matter falling into the BH in the accretion process does not all land on the compact surface and this second object is where it may emerge called a white hole (WH).
This may inhabit the Galaxy centre and not a SMBH. We may be the recipient of matter from a BH elsewhere in the Universe. Attempting to prove the properties of what may be a massive white hole are unnecessary. By looking at the causal link and association described above between Galaxy features and the central object can determine its properties.

Contrasting galaxy features to a merger process in the Standard Model with a SMBH and comparing this to a more relative process with a Super Massive White Hole (SMWH) in the Galaxy middle will show which is more credible. In the Relative Model matter emerges in the centre and spirals away to be constantly replaced in what is basically a growth process. Comparing these two models with regular features of galaxies will determine that no feature can be associated directly with merger and all can be connected with a growth process.

Merger of Galaxies v Relative Growth.

The Relative Model suggests expansion. Matter in the Galaxy spirals away from the centre and is constantly replaced. As the galaxy grows so does the SMWH forming a correlation in size as the central object takes 0.5% of the passing matter. It also suggests that only one SMWH is needed, you won’t find two or more, and always in the Galactic centre like an axis around which all matter will rotate. Mass expanding from the middle will give galaxies a circular and symmetrical character with the SMWH right in the heart. 

The Standard Model predicts a more chaotic galaxy. Even a ‘sympathetic’ merger where two galaxies come harmoniously together will overlay features like spiral arms and bulges to form concentrations of stars, odd shapes and deformity. 

                                           Circular and symmetrical galaxy.

Matter expanding from the SMWH in the Relative Model will respect the magnetic field of the central object initially and simply continues that motion forming a vast disc. It would be unlikely that even a super massive central object could dominate matter over the full width of a galaxy. 

New stars forming around the SMWH will give them an even and near circular orbit. The amount of very irregular or elliptical orbits will be low (maybe less than 1%) and incoming stars from merger will create a high percentage of elliptical orbits (40-50% would not be unexpected). The actual amount of elliptical orbits is very low which is not associated to the Standard Model.

The Relative Model suggest that the bulge is a huge star-forming zone with matter pouring from the SMWH forming stars that spiral across the galaxy over time. This makes it full of young stars whereas the Standard Model suggests it is full of old, however, when the ages of stars are analysed they appear to be largely young. This is called the ‘paradox of youth’ and is not related to the Standard Model.

If the Relative Model is true and the bulge is a huge star-forming region with stars spiralling away over time then they will be generally aged, right across the Galaxy, according to distance from the centre. This suggests younger stars are found at the bulge and the older at the edge of the glowing galaxy which is in general what has been established. (M. Arnaud. ‘The Evolution of Galaxy Clusters Across Cosmic Time’ 2010)

Unlike much discussed here where the Standard Model may, at a pinch, be viable it is impossible for the random, chaotic, and disruptive merger processes to form a grading of stars in age according to distance from the bulge.

What the glowing galaxy represents is the evolution of stars. They predominantly form in the bulge (barring some notable exceptions like special star-forming zones called nebular etc and the possible condensing of stars from clouds of matter in the general interstellar medium) and spiral away over time to eventually die. Stars have a lifetime and this is represented by the bright galaxy. Though they must eventually go dark it is not the end of the matter they are made from. That will continue to spiral away forming the Dark Halo as a star grave yard. So the whole galaxy is the sum of mass passed through the bridge over its lifetime. 

                                         Dark Halo around galaxy showing graveyard of stars.

Galaxy size.

The Relative Model suggests a steady outward flow of matter creating a growth process so galaxies of a similar age may have a similar mass. Plotted on a graph their sizes will fall into a growth curve. This is called Freeman’s Law. In the Standard Model galaxies start small and randomly merge which will not result in galaxies of similar large size. 

The Sun.

The sun is not orbiting in an exact circle around the galaxy. We are gradually moving away as a likely illustration of outward drift. The Sun may have formed in the bulge with most of the stars around us from matter passed through space time and we have gradually spiralled away over the Sun’s lifetime.

Spiral Arms.

These features are not random. They are connected to a bar of stars that crosses the centre of the bulge right through the SMWH. Matter as two streams like huge jets steadily move away through outward drift and are replaced from the centre as part of the Relative Model. As they pass out of the direct magnetic field of the SMWH they form two spirals as part of outward drift and rotation. These arms are the bar of yesteryear.

                                       Bar of stars represents outward drift that become spiral arms.

The interaction between these two jets of matter and a SMWH or a bar of stars and a SMBH in the Standard Model (there must be some as they occupy the same space) are not an interaction recognized about BHs.

Bar formed by two massive jets from equator of SMWH  (not BH)

None of the galaxy features described here can be associated with merger - all can be linked to growth. Some of the reasoning’s in merger are difficult to believe but a few, the ageing of stars from the bulge and the formation of the bar, are impossible.

The Black Hole/White Hole connection.

Any theory concerning BH must be part of relativity. This predicts that very compact, very heavy and fast-spinning object’s strong gravity may bend and warp space time theoretically forming a time tunnel or well into the past. 

                                                   Grid depicting time warped by gravity

The problem with time tunnels concerns any physical representation. A two dimensional grid which is warped by the intense gravity can’t be how time is represented. It’s not a physical entity in itself nor is it a force. Time is in theory a fourth dimension and these are the characteristics and properties of matter. So anything with gravity can, supposedly, slow time. Our planet has a small but detectable effect and the Sun will have more. Even an atom has gravity so must have, in theory, an effect on time. If a place existed in the Universe that has no matter it would have no time and a relative tunnel cannot end without any time. What is needed to complete the picture is a second entity. Like a secondary star to the BH associated through space time and evolving with it to form something like a WH. 

Very early in the BH evolution a body was associated (as part of the birth process) through the properties of the Supernova forming a partnership via space time. This relative model implies the connection between the BH and WH is a time bridge which may have a specific and detectable structure.

Black Holes, Time Bridges and Accretion

Matter in accretion rotates into the BH around the equatorial region forming a disc. This matter increases in speed due to decrease in orbit. At the inner accretion zone it may convert to antimatter. That may be gravitationally negative and violently repelled by the BH. Not back into space but up the time bridge. 

Matter falling into the equatorial region in accretion will pass half north and half south. This ejects both sides of the BH suggesting the time bridge to be connected to the poles as a double tunnel. This avoids contact with matter in the accretion disc as antimatter is highly volatile.

                                     Accretion Disc represents matter falling into Black Hole.

                                      Unseen matter flow and Time Bridge construction.

As the BH rotates it twists the two time bridge filaments over each other creating a spiral called a double helix. At the WH end the time bridge interacts predominantly in two points forming two huge jets of matter that produce the bar of stars. It’s a double both ends and in-between.

                                       Non Thermal Filament is Time Bridge.

These non thermal filaments have the correct structure predicted by this theory so are not likely to be formed by other fundamental processes like dark matter. They glow due to the exciting of antimatter by matter that may penetrate the time bridge. Not large objects that are gravitational, as they may be repelled, but charged partials which are unavoidable. It is antimatter that arrives at the SMWH which is repelled forming the general outward drift scenario across the Galaxy with only a small proportion (0.5%) being absolved by the SMWH. Once in the Galaxy antimatter violently reacts converting readily to energy and matter generating the Torus.

Other evidence for the double time bridge is located near the BH. A visible interaction between matter and antimatter may occur at the outer accretion zone. If the time bridge is wound close to the BH matter from the disc may pass through the forks of the bridge creating an intermittent and visible hot spot on the outer accretion zone. This hotspot is predicted by this formation and so is unlikely to be associated with other fundamental processes.

Matter Transfer and Nebular

The BH evolution will predict the effects at the associated WH. If the BH catches a partner like a random star in forming a high mass x-ray binary, not low mass, then during a pass matter is striped, accreted and conveyed to the WH elsewhere which may flare, form a Be star with unbound mass or become shrouded in a cloud. If the BH evolves in more matter rich environment like inside the bulge enough may be accreted to start the formation of stars around the WH in a cloud called a nebular.

                                                       Cloud around Be star.     

                                            Nebular.

It is the gravity of BH that commence the star formation process in the Galaxy at the centre or in specific star forming regions and maybe not usually by the collapsing of general clouds of matter into stars in the interstellar medium. Which questions matter evolution by cycling via generations of supernova and reformation into stars. This also questions the evolutionary path of the solar system in elemental composition.

If the BH evolves close to the matter rich galactic centre the time bridge conveyance may be large enough to form huge clusters or even dwarf galaxies. That these features are not captured but home grown.

The two dwarf galaxies close to the Milky Way suggest two BH of large size close to the galactic core. One BH may have moved causing accretion to falter, matter transfer will fail and in the dwarf galaxy stars are not replaced creating an empty middle - this is how galaxies die.

Evidence for these connections can be found in the time bridges that weave across the galaxy. They appear to radiate from the bulge as this is the only place in the galaxy were a BH can become big enough to attract substantial matter to form a large time bridges.

                                            Filaments passing matter across galaxy

SMWH and partner BH

The bridge between large BHs close to the galaxy core and huge clusters must remain stable for long term transfer. This suggests time bridges to extend over great distance and be remarkably stable. They must survive inevitable high energy interactions as they pass through the galactic plane; through the bulge, other time bridges, the bar of stars, the SMWH etc. By their apparent abundance they must be stable, stretchable and robust.

How far they can span may be indicated by the association between the SMWH and its BH partner. This must be of huge size to attract enough matter to feed a galaxy and the only candidates are quasars which cannot be found isolated or even in another galaxy. They must be in a place of almost limitless matter and luckily there is such a place - the early expansion fazes of the Universe, soon after the Big Bang, where all mass was thought to be formed. This is the place we also find quasars. So the only objects possible are in the only place possible. We are connected through most of space time via the interaction of Mass Time and connected under one amazing theory (relativity). Evidence for this relationship comes from non thermal filaments that cross the Universe like arteries passing matter, that are time bridges, to expanding galaxies.

                                      Non thermal filamentary time bridges from quasars to expanding galaxies.

The connections do not end there. In order for a WH to evolve into a galaxy the time bridge alliance must be made first then the matter transfer can begin. We use the speed of light as a recognition of time to look back into the deep field of the Universe to when the Milky Way was smaller, back to when we were a dwarf, a cluster, a nebular, a Be star then to the connection. 1 billion years from the Big Bang galaxies are already visible so the time bridge connection form deeper within this early expansion suggesting a connection in this very early phase.

Probably the first stars ever to collapse their cores in the creation of BHs via a supernova that forged the association and then diverged in space time. One object to form the Galaxy the other to become so large and gravitationally powerful it almost stops time. Remember, the greater the gravity the more time is slowed which also suggests WH characteristics do not substantially slow time (only semi compact and not rotating*). In a sense these quasars are extending the fundamental process that forged all mass. What may be billions of years of evolution for us may be a small stretch of time for a quasar. What happens to us in our journey and what happens to quasars in theirs (and everything proposed in this paper), in what amounts to the evolution of the Universe associated with the interaction between mass and time, can be summed up in one simple equation. U=mt

Were; Universe = U.     Mass = m.     Time = t

Change time to speed of light c² (as a constant and recognition of time)

U=mc² 

And relativity is 

E=mc² 

The Universe is all energy and it’s formed by the interaction of mass and time through the properties of BH / WH partnership as described here and predicted by relativity.

*Matter coming from around the WH may have super fast rotation as antimatter may travel in the bridge near the speed of light. The association with the BH suggest the WH is not rotating.