I'm truly interested -- as he is a dabbler in the astronomical, and I am a sci-fi geek.
I feel like he'll have some true, physics-based reasoning, while my mind spins at this:
Some physicists have theorised that black holes might act as spacewarp wormhole portals into alternate universes, or something. Summarising, it appears that the boffins at the LHC - should one of them clumsily spill his tea on the controls, for instance - could easily catapult the entire world through a rift in the very fabric of space-time, into another universe which could be entirely hostile to life as we know it. (Eg, essential processes such as fermentation of alcohol, TV, pizza delivery, gravity etc might simply not work; or there could be a parallel Earth ruled by an evil victorious Nazi empire with space battlecruisers and so forth.)
No pizza delivery? The HUMANITY!
Nazi alternate universe? didn't I read they're making a movie out of that book?