THE DIPOLE REPELLER
"Astronomers have discovered a vast, extragalactic void they call the Dipole Repeller, that appears to be pushing our Local Group of galaxies away from it." -- Daniel Pomarède

Galaxies (or anything) cannot be repelled like that.
What is actually happening is there is more pull / gravity coming from a normal area region NA

NA ~~~~~~~~ MG ~~~~~~~~ VOID

Milky Way Galaxy MG is NOT repelled by the Void -- it is pulled towards the Normal Amount of galaxies NA. That is the way gravity works even at large scales -- stuff pulls together
MG will be drawn towards NA because the VOID has no large masses in it.

If there are a bunch of galaxies evenly spaced -- everything will pull on everything else equally -- no big changes

A~~~B~~~C~~~D~~~E~~~F~~~G~~~H

But if there is a VOID -- for instance no galaxy D

A~~~B~~~C~~~~~~~~E~~~F~~~G~~~H

then everything else will pull away from the VOID because there is more mass on either side.
C will be drawn towards B
E will be drawn towards F
That will just make the VOID a lot bigger and more menacing and it will keep getting bigger.

A~~B~~C~~~~~~~~~~~~E~~F~~G~~~H

How could a VOID initially start though? That could be just a random thing that happens. Everything is moving around and just by happenstance a spot develops with NOT a lot of material in it anit and it continues to grow -- or should I say ungrow.

Think about it for 20 years if you have to.
Here is the way Everything works...

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QUANTUM THREAD THEORY
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Space is NOT empty. There is an all encompassing lattice-type thread particle network in space. It is gravity centered -- Einstein called it Space-Time. Otherwise known as the Fabric of Space. (yes, the fabric of space must actually be made from something)
A good 2-D model would be something like a spiders web made of the finest web-silk-thread filament. Now imagine a 3-D web.
It is made from individual yet connected thread particles and of course the web has tension on it (that's were gravity gets its pull). The speed vibrations travel through the web is the speed of light (light is a just a vibration travelling in a thread particle network)

Here is a regular thread tension formula...
Tension = velocity squared x mass / Length
If we plug in c and rearrange we get the one-inch formula...

TL = mc^2

If the tension goes up... gravity goes up, and so does the speed of light and everything else with it.
That includes any type of measuring device, the speed your brain is working and time itself.
Increase or decrease tension and it changes everything along with it, that's all electro-magnetic phen, vibrations... everything.
It's like being a character in a movie and you don't know the speed the projector is running... fast, slow, stop, start... you don't know.

Now we know were energy comes from and why light travels at c.
Tesla was correct...
"There is no energy in matter other than that received from the environment." – Nikola Tesla

Mnemonic memory device...
E for Einstein: E = mc^2
TL for Tesla:  TL = mc^2

"Matter" is just balled-up / clumped up parts of the same particle network.
What they call "Dark Matter" is completely filling space -- it's the particle network itself. The clumps around galaxies and other spots are excessive amounts.
Dark Energy is tension on the network as a whole. Everything is being pulled on equally. Any masses in the system create a higher tension pull between them -- that's gravity

Here is a link to the whole theory...
http://www.mccelt.com/the-one-inch-equation-to-explain-all-physical-laws.php