A REALLY Big Bang

A questioner at the What-If site of xkcd.com asks what would happen if the Earth were made up entirely of protons and the moon entirely of electrons.

The longer explanation can be found at the link, but the spoiler version is that while the proton Earth might be kind of catastrophic, the all-electron moon would create a special kind of black hole that would warp space-time around it and might even spread outward and destroy the universe. Obviously, since this has not happened to us yet -- the best efforts of the folks at the CERN Large Hadron Collider notwithstanding -- our moon is made up of ordinary atoms and not electrons by themselves.

If it ever does happen, the destruction will spread outward at the speed of light. Which means it would take millions or billions of years to reach distant galaxies or the edges of the universe, who would not know what horrible fate is hurtling towards them.

Since that already happens every time Michael Moore opens his mouth in range of a microphone and that signal is sent outward from Earth, our perfectly ordinary and non-cosmos-destroying moon doesn't mean we get off the hook just yet.