From the Smithsonian’s Dinosaur Tracking blog:

Somewhere, out in the interstellar void, there may be a planet inhabited by hyper-advanced dinosaurs. At least, that’s what a new paper by Columbia University chemist Ronald Breslow says. One idea, favored by Breslow, is that meteorites carried specific types of amino acids and other organic flotsam to earth around 4 billion years ago. This is an extension of the idea that life here was “seeded” by comets, asteroids or meteorites. The origin and subsequent evolution of our planet’s flora and fauna would be constrained by the characteristics of the biomolecules that gave life a jump-start. None of this has anything to do with dinosaurs. (The first dinosaurs, as far as we know, originated a scant 230 million years ago.) Yet, in closing, Breslow briefly speculates on what alien creatures might look like—perhaps possessing the opposite biochemical orientations of life on earth. “Such life forms could well be advanced versions of dinosaurs,” Breslow writes.

As much as the idea of alien dinosaurs is charming, Breslow’s conjecture makes my brain ache. Our planet’s fossil record has intricately detailed the fact that evolution is not a linear march of progress from one predestined waypoint to another. Dinosaurs were never destined to be. The history of life on earth has been greatly influenced by chance and contingency, and dinosaurs are a perfect example of this fact.