66 million years ago, dinosaurs ruled the Earth. They were everywhere, they came in every size and shape. They crawled, walked, flew, swam, and filled nearly every ecological niche one might imagine. The Cretaceous hadn’t been very kind to them, but as living creatures do, they had adapted over time. They’d grown smaller, leaner…smarter. They lost height and girth and gained feathers. Through careful evolution and luck, they had held dominion over their planet for nearly 180 million years.
They’d had a good run.
On this day, the sun would rise over Cretaceous swamps for the last time. Across every continent, in forests and marshes and open plains, countless creatures went about their lives as they had for ages, foraging or hunting for their next meal, mating and fighting, tending their eggs, oblivious to what was to come. As they blundered on in ignorance, far from their young world an instrument of death tumbled toward them.
Millions of years earlier, a cosmic accident had jostled an asteroid out of its orbit around the sun, and set it reeling toward Earth. It was likely a bolide: a dense, metallic boulder some 10 miles in diameter. Now, after years of sailing through space, its journey would end on an otherwise ordinary morning. It would strike the Earth at what would one day be the Yucatan peninsula with the explosive force of a billion nuclear bombs. In the aftermath, debris ejected into orbit would fall back to Earth like a rain of fire. Dust in the atmosphere would blanket the world, blotting out the sun for an entire year as prelude to a long impact winter. The dense cloud would turn the Earth’s protective atmosphere into an oven, trapping infrared radiation so that lifeforms on the surface would literally be cooked alive. The impact would be so intense, the effects so far reaching, that it would leave a layer of iridium an inch thick across the entire planet. Those that survived the blast would sweat, starve, and die.
In the wake of this cataclysm, a great dying would occur. Eighty percent of all life on Earth would starve, suffocate, or succumb to heat or cold as the global climate reeled. In the end, the terrible event would benefit only a select few; small, endothermic creatures that had scurried about at the feet of giants. They were furry and furtive, hiding in burrows by day, subsisting on insects and pilfered eggs, living in perpetual fear of the huge, nightmarish predators that ruled their world.
But then, on the fateful day when the bolide hit and the lights went out, their ability to regulate body heat proved to be their saving grace. Over time, they would be fruitful and multiply, conquering the Earth as they filled the vacant niches left by the thundering lizards. They would diversify and adapt, proving even more adaptable than their predecessors, and they would thrive in an era when Earth’s climate was far more volatile, far less forgiving. In time, those tiny creatures would evolve into other rodents, into the curious platypus and the hopping kangaroo, the lightning-fast cheetah and the powerful tiger, the towering bear and the furtive lynx, the solitary leopard and sociable wolf, the miniscule shrew and the mammoth blue whale…and, ultimately, into us.
Except it didn’t happen. Not this time. At the last minute, something changed; the slightest nudge, barely shoving the asteroid clear. The bolide misses, passing Earth harmlessly before careening off into the void. In the forests and swamps, the dinosaurs lumber on, blissfully unaware. High above, far from the unsuspecting planet, a tiny spacecraft sits parked at one of the Lagrange points, its work complete. The crew aboard congratulate themselves; they’ve just saved millions of lives, prevented the extinction of roughly three-fourths of all species on the planet, not to mention the ecological catastrophe that would have resulted from such an event.
Now, in all fairness, these hypothetical alien beings could have no real idea of what the future would hold. How could they possibly know that their single, seemingly charitable act could prevent the construction of the Great Pyramids, or the Great Wall, or the Flavian Amphitheater, or the Burj Khalifa? How could they realize that in one fell swoop, they had prevented the births of Albert Einstein, Stephen Hawking, Wolfgang Amadeus Mozart, William Shakespeare, and Leonardo Da Vinci? That through their efforts, great works of art, literature, science and philosophy would never be produced?
Of course they could have no idea. These men would not be born, their great works not produced, for millions of years. The world they would be born to would look vastly different from the primitive jungles and marshes of the Earth walked by the dinosaurs. It would be colder, less connected, more diverse, and certainly a tougher, harsher place; the kind of place that breeds intelligence by rewarding cunning. Earth’s alien visitors, even with their ability to easily traverse vast interstellar distances, could not possibly know that. All they could know is that an entire ecosystem of interesting, diverse, wondrously unique creatures was about to be erased from the universe forever. They prevented that, and no doubt they would give themselves a well-meaning pat on their collective backs before speeding off into the cosmos.
So, now what?
Things might not turn out as differently as we would imagine. While the Chicxulub impact certainly did a number on Earth, its effects were far from permanent. In fact, the trend of global cooling, while surely accelerated by the impact and the resulting impact winter, had been progressing for much of the cretaceous. Extensive volcanic activity across North America and the Indian subcontinent wreaked havoc on the environment.
In the end, many of the climate factors that led to mammalian intelligence would have affected the dinosaurs. In time, they might have learned to walk upright as we do, to wear the pelts of their kills for warmth, cook their food over fire to make it easier to digest. Carl Sagan once famously speculated that, had the Chicxulub impact not occurred, the dinosaurs would have eventually developed math…on a base eight scale rather than base ten, owing to their four digits on each hand as opposed to our five.
And perhaps, in time, the dinosaurs would have found their voice, and their muse. Perhaps they would have produced their own Einstein, their own Mozart, their own Sagan and Shakespeare and Michelangelo. It’s possible. Would it have happened? Well, we don’t know. All we know is what did happen. And that is where this comes to feel unfair.
The fact is, the meteor was not diverted. The bolide did strike Earth, and millions of lives were lost. Entire species were relegated to the fossil record. No doubt, many more were not fossilized, lost permanently. But one species’ loss is often another’s salvation. We know what happened after the impact. Who are these hypothetical aliens to decide whether or not things might have turned out better had the dinosaurs survived?
It has been said that with great power comes great responsibility. Based on our current technological development, it is safe to assume that, one day, we will possess the means to travel between the stars. With that ability will surely come yet other technologies, enabling us to bend nature to our whim, from terraforming to the ability to divert asteroids. Yet with this awesome power will come the imperative to use it responsibly. We must bear in mind the lessons learned from our own history, from the history of our planet. We must understand that, while many extinctions on our planet have been our own doing, many others were not. Sometimes, species go extinct. It happens. When the climate of any planet, even our own, undergoes a dramatic natural change, some species can adapt, but many others will not. Call it fate, if you will, but it is necessary. When one species faces extinction, it may open the door for another to flourish. Who are we to decide whether that is for the best or the worst?
Since our first fossil finds, the dinosaurs have captured humanity’s collective imagination far more than any other species that once roamed the Earth. Vast amounts of fictional material have dealt with the possibilities of reviving the dinosaurs, or of what might have happened had they never gone extinct. Regardless, in the end the dinosaurs did not succeed, and we owe our existence as a species in large part to their failure. Hopefully, when the time comes, we will bear this harsh reality in mind, and refrain from allowing our compassion to deviate the course of another planet’s history.