Wormhole the Moon through the Earth

[dQniel]

I'm working on a potential sci-fi story that takes place on a post-apocalyptic Earth. The idea is Something Horrible 1A happens, then, 15-20 years later, Something Horrible 1B comes to finish us off. In a perfect world, the Moon is gone after 1A.

Initial possibilities included a long orbit double comet (first hits the moon, destroying both and partially wrecking Earth), then the twin comes around (follows-up) a couple decades later to hit Earth and finish the job.

Then I started wondering what would happen if a wormhole experiment on the Moon went awry, wormholed the Moon through Earth to the other side? Would the energy/radiation of the event wreck Earth enough for 1A? Basically, what would happen to Earth?

Then, would it make "more sense" (in this completely science fiction scenario) for the Moon to return 20 years later near enough to the Earth to crash into it, or to reappear immediately in a 2 decade slow degrading orbit?

 

[Ophiolite]

Regarding the comet scenario: comets are not large enough to destroy the moon. You need a minor planet - excuse me, dwarf planet. Were you able to destroy it, I doubt you could avoid total destruction of the surface biosphere of the Earth from the resultant debris. (It wouldn't take many of the remnants striking Earth to render it uninhabitable.)

Since your wormhole idea appears to be based more on the popular notion of wormholes and not on any of their scientific aspects then you could probably have its side effects be whatever you wish them to be. Is there a reason that you wish to use an astronomical source for your apocalypse? Why not jump on the global warming bandwagon and reach the tipping point where methane is released from the methane clathrates on the ocean floor: massive global flooding, destruction of ecologies, raging storms, intolerable temperatures and the end of test match cricket.