Just because the speed of light prohibits us from observing beyond space time limits does not mean that there is nothing there. 

I have long believed that the Hubble constant was the result of illusion.  Although your mega-galaxy is a real possibility,  I tend to

believe that the source of the illusion is found in the properties of light.  Every observer is at the center of its own observable universe. 

I maintain that this is a fundamental property of any mega-universe.  The limits of observation are always confined to the location of the 

observer.  Draw three spheres of observability.  Two intersecting, and one outside the other two. 

If ours is the one outside the other two, 

then we may not observe the intersecting universes, nor they ours.

Observers inside either of the other two spheres would be able to observe only the information found in their respective spheres, some of which

would be common to both spheres of observability. 

I maintain that the mega universe is infinite and full of such spheres of observability. 

Unfortunately,  at this point in time I cannot prove it, but some have begun listening.  

Keep up the quest.  Some are on the right track. 

A question:  Does gravity affect objects outside the sphere of observability?

Paul

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The music doesn't have to end with the last note!