For most of them, it was the night sky that gave the first clue. They used social media to meet up, to stand together, ooh-ing and aah-ing as a constant stream of shooting stars rained down on Earth for almost four whole days.
But their leaders knew better.
No artificial satellite could survive that bombardment. Blinded, they could do nothing but await the inevitable arrival of the asteroids.
Of the eight we sent, only five hit – one missed completely, and two glanced off the atmosphere. Nevermind, it was sufficient.
The humans had no colonies. They are no longer a threat.
Author’s Note: Despite what some books and movies may tell you, there’s no reason why aliens would invade Earth. Killing us from afar is a much more efficient way to remove a resource competitor.