What If The Asteroid That Killed The Dinosaurs Happened Again?

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What If the Asteroid That Killed the Dinosaurs Happened Again?</h4>

The asteroid that ultimately killed the dinosaurs was 6 to 9 miles. When it struck Earth, it left a crater 93 miles wide. It released the energy equivalent of 10 billion Hiroshima bombs, triggered near constant fires, and possibly plunged the whole world into a years’ long darkness. Do you think we could survive the same again?

In the entire, 4.5 billion-year history of Earth, there are certain, crucial moments that have truly shaped and guided the story of our planet. The abiogenesis of life is one, the emergence of modern humans is another… the end of the dinosaurs is another. According to the most widely accepted theories, this demise was triggered by a cataclysmic asteroid strike, with a fateful rock from space crashing into our world along the Yucatan Peninsula in what’s now Mexico. It happened 66 million years ago. It wiped out upwards of 75% of all plant and animal species, including all non-avian dinosaurs. And to some degree we’re still feeling the effects of it. So, what if something like it were to transpire for a second time?

This is Unveiled, and today we’re answering the extraordinary question; what if the asteroid that killed the dinosaurs happened again?

Cast your imagination back to Earth, 66 million years ago. It’s a tricky task because, really, we need to think of a very different planet. The climate, the atmosphere, the basic layout of land and water… nothing is like it is today. There are long stretches of extreme heat, far outstripping even the hottest conditions in modern times. The humidity is also extreme, and the air is choked with four times the amount of carbon dioxide. There are complete land bridges, connecting whole regions, that have since been covered over with the water of the oceans. If you were to somehow be magically transported back to then, it’s a fair bet that you might not even recognize Earth, at all. That it might just as well double up as an alien planet, thanks to the many, many changes that have happened in the millions of years between then and now.

Nevertheless, and according to most models, we do know of at least one key aspect - one key moment - from all those years ago. We know that, at some stage, Earth experienced a very bad day. An asteroid, at least six miles wide, slammed into what’s now Mesoamerica. This was the Chicxulub impactor and, when it hit, it unleashed unimaginable energy, equivalent to millions of atomic bomb detonations. Much of the local area was instantly vaporized. Huge shockwaves rippled across the globe. At the time, the dinosaurs were the undisputed rulers of our planet, towering over every other living thing, at the top of a food chain that may well never have crumbled if Chicxulub hadn't happened. But, it did happen… and history shows how it triggered a monumental shift. 

It wasn’t that the asteroid instantly killed all the dinosaurs. Although it’s often misunderstood to have been a true before-and-after moment, in reality it wasn’t quite so quick. The impact triggered unprecedented weather events, which over time caused the atmosphere to settle back differently. Some of the dinosaurs did perish within just weeks, months and years… but many clung on, perhaps for as long as 10,000 or even 100,000 years post-asteroid. Ultimately, though, the ongoing, lingering, and in many cases irreversible effects of the rock did make it impossible for the dinosaurs to continue. They went extinct and, while we do have crocodiles, some ocean creatures and most birds who are directly related, as a whole they never came back. 

In their place, Earth witnessed the rise of the mammals. It was a rapid ascension from small, shrew-like creatures to a constantly expanding, rich and diverse, new class of animal. They could thrive in a new world without the energy-consuming, nature-shifting, mammal eating dinosaurs of before. And, of course, from there, eventually, we were born. The timeline of humankind is long and complicated in itself, with offshoots all over the place and various other key moments that combine to form our story. But, the long and the short of it is that, had the asteroid not hit… then we wouldn’t be here. We effectively owe our lives to the asteroid that killed the dinosaurs.

So, with all of that considered, what would unfold if the same thing really were to happen again? What if the universe had another cosmic bullet in the barrel, and what if one day it were sent hurtling towards us for a second time?

Thanks to modern technology, we likely would at least know that it was coming. Our skies are now constantly scanned with an ever-increasing arsenal of cutting edge telescopes. But, nevertheless, upon arrival the immediate scene would be much the same as it was for the dinosaurs. The sky erupts in a blinding flash that’s far brighter than the sun, or even multiple suns. The light engulfs the landscape, breaches the horizon, and spreads. The asteroid has entered into our atmosphere, and is burning at temperatures exceeding thousands of degrees.

Seconds later and there’s a deafening roar; a sound unlike anything that humanity has ever heard. It rolls across the planet, permeating everything that’s around you at the time. Then, if you’re close to the impact zone then, well, your life is already in extreme danger. If you’re on the other side of Earth, then perhaps you’d feel a little safer. But, really, everyone should be terrified. The shockwaves of the strike reverberate. It levels buildings, shatters glass, rips through roads, houses, towns and cities. There’s a long sequence of massive and devastating earthquakes and tsunamis. Coastal cities could be wiped off the map within minutes. Tectonic fault lines would break. A huge number of volcanoes would be at risk of eruption.

The unimaginable energy involved means that an endless stream of superheated dust and debris is launched into the sky. There’s a growing and deadly cloud of choking material that soon infiltrates the atmosphere properly. And, if it wasn’t bad before, now’s when things really heat up. In the very worst case scenarios, the scorching ejecta blocks out the sun. And not just for a couple of hours. As they were for the dinosaurs, these terrible changes are for the very long term. We know that Earth is resilient and that, over thousands or millions of years, it will survive. But the new conditions would certainly be a death knell for the vast majority of life on it. Mammals, while reasonably hardy, are in many ways less prepared for global disaster than the dinosaurs would’ve been. Humans, for all our supposed intelligence, would also be at a complete loss in the face of a new normal that simply wouldn’t accommodate us.

With the new atmosphere thickening into something like a toxic soup to drown in, even once the initial temperatures post-event start to fall… there still isn’t much hope. With the life-giving sun now struggling to break through, it should actually get colder and colder across the centuries that follow - a phenomenon otherwise known as an impact winter. Any crops that did survive the strike itself would ultimately fail. Forests would wither. Photosynthesis would shut down. The delicate balance of the food chain as we know it would collapse. 

Human society, which is ultimately built upon all the expected patterns of the current natural world, could never hold up even if there were surviving humans to populate it. Supply chains, travel links, communications networks, clean water systems, they all would break and would soon be forgotten. In their place, and over time, Earth would play host to new fundamentals. New soils forever peppered with the burning ash of the asteroid strike. New land masses, freshly shaped following the initial turmoil of the event. Unknown air, breathable to some perhaps… but not to most.

How do you see it going from there? Let us know in the comments. Importantly, humankind does possess an ingenuity that the dinosaurs didn’t, so perhaps there is some hope that if anyone survives… then they might be able to build our species back up. In the style of science fiction, though, the last humans would need to escape underground. They’d have to, in some way, live below the surface that could now offer them very, very little. The once sprawling cities are gone. Because, while most probably would survive the asteroid itself, none could carry on operating under Earth’s new rules. To our minds, it would be an apocalypse, just as it was for the dinosaurs.

For Earth as a whole, an asteroid strike is something like a hard reset. In all likelihood, new forms of life would emerge, just as they did during the rise of the mammals. But the details of that life are impossible to know. Perhaps, in another 66 million years or so, evolution will’ve continued in such a way to spawn another species that’s intent on finding out more… but, in truth, there’s little reason to believe that anything even like a human would happen again.