Tweet of the Day: Keeper of the Dark Things
When you need to upgrade your arsenal of mass destruction from the ye old nuke, you summon this trope. Take a sufficiently large object and pointed at an inhabited planet. Velocity x Mass will take care of the rest. It can be as effective as a tactical nuke or lead to a extinction level event. This trope, in spite of the picture above, does not apply to chance encounters between space debris and a planet. No, in this case someone wants to destroy a surface target with extreme prejudice. If we are talking about planetary bodies (at least asteroids or comets) overcoming the inertia of the body is key. In the case of man made objects, the size and velocity are the main factors.
The object need not hit the surface, an air burst can be just as deadly, if not more so. If the planet has an atmosphere, it not just about the impact itself, shock waves, particulate matter and even radiation are all a factor in the overall destructive force unleashed by this attack. In most post WW2 science fiction stories (E.E. “Doc” Smith’s Lensman series used entire planets) this tactic will be treated as a weapon of mass destruction and restricted in some way since it can kill anyone living on a planet. Expect heavy sanctions on anyone who crosses this threshold. Therefore only the desperate or the evil will use such weapons.
Makes for a great way to ratchet up the action.