The Galactic Centre is home to a massive black-hole, estimated at ~4 million solar masses, meaning it’s event horizon is 12 million kilometres in radius. Not the biggest – there are multi-billion solar mass black-holes in the cores of other Galaxies – but big enough. And now there’s this mystery of the Missing Stars. The astrophysicists are modelling natural explanations, as that’s a reasonable assumption, but I’m with Greg Benford – the Core is full of mass and energy. If advanced civilizations are astroengineering on a large-scale, then the Core is where it’s at.
One possibility is that the black-hole is surrounded by collapsed remnants of stars, like stellar black-holes and neutron stars. In my mind if there’s any chance a natural black-hole can be made into a wormhole, then that’d be the place to do it. That ETIs might be shepherding the stars in that region, could also explain the odd lack of visible stars near the Core. Carl Sagan’s old image (in the 1985 “Contact” novel, not the 1997 movie) of a Galactic Grand Central Station for wormholes might actually be true!