Gigaverse Theorem: Mass Increases with Time

Theorem: The universe is expanding, its mass is too.

Proponents of Big Bang often miss the obvious solution to the mass problem. Some call on dark matter or other mysteries to fill the void.  Far from such ethers lies a simple solution, one which integrates higher-order structure and proposes a simple and obvious mechanism.

Let's assume for a minute that what lies at the centre of our galaxy is super-massive, perhaps a black hole>  Or, could it be a wormhole, which links different universes together, sort of a Gigaverse.

It's like a spider spinning out a web, the Milky Way, throwing out stars at the event horizon and perhaps even pulling things in, as Hawking proposes. What experiment or observation could be helpful in assessing the hypothesis?