Watching the sun rise this morning, I was observing the crepuscular light shedding angular dusty beams on the Eastern horizon. One beam of light was shining vertically through the clouds like some massive laser. Which made me think about alien invasion movies like ‘Independence Day’ where the invaders come zooming into Earth’s atmosphere with massive energy weapons, blowing up everything in sight. Thinking about it, why bother with Star Warsy / Trekkie type energy weapons? All very sparkly, all very pretty, but mostly all heat and fury with very little knockdown power. Comparatively speaking.

Now if it were me, I’d drop half a dozen or so hundred metre asteroids on the planet well before sending in ground troops. Any detonations, even within a kilometre or five of the surface would do enough damage to a major cities infrastructure to paralyse everything. Then leave for a year before hitting with another quick barrage of about ten Tunguska sized masses. Wait another solar year while all the humans run around shooting each other and running out of supplies before sending in my very expensive, and hard to fix number of terminator ‘droids. Minimal damage to the biosphere and game over for all those pesky humans. And some very nice living space on a des res planet once the meteoric dust has settled and things have warmed up again. Just send in the scrap scavengers.

Fortunately it’s all fiction. Because if any other species is smart enough and capable of crossing interstellar space en masse with hostile intent; basically, humanity is screwed.

Update: as opposed to airbursts, what if the asteroids were dropped in the seas near major coastal conurbations? A big enough water explosion a hundred and fifty klicks away would mess up LA, San Francisco and San Diego with Tsunamis. South and East of New York to push a wall of water up the Chesapeake. One in the Northern Caribbean would paralyse Florida and all of coastal Texas, as well as sending a massive tidal bore up the Mississippi. Polish off with a hit in Lake Michigan. Europe could be paralysed with three hits. One in the Northern English Channel, Eastern Baltic and central Mediterranean. Western Indian Ocean about equidistant between the Persian Gulf and Mumbai. The last reserved for somewhere in the Philippines. Residual tidal surges would at least severely damage every sea port everywhere in the world. Two years of solid rainfall from all the atmospheric water vapour would do the rest. Result: one freshly laundered planet ready for colonisation. Scary.