Classic Harry Turtledove story from 1985, in the Golden Age SF vein (compare to Clarke's 'Rescue Party'). It's a prequel to Herbig-Haro, which mostly inverts the idea. You can also view it as a precursor to Turtledove's Worldwar series.
But as the pastebin is a blatant copyright infringement, and the story isn't new, I don't think it's appropriate for HN.