According to an upcoming BBC documentary, location, location, location made all the difference for the dinosaurs when it came to a mass extinction event 66 million years ago. But the dinosaurs' loss was our gain, as this cataclysmic global die-off paved the way for the rise of mammals–and humans.

Researchers believe that if the 9-mile wide asteroid had made impact less than a minute before or after it did, it likely would have crashed into the much deeper Atlantic or Pacific oceans, and not in the Gulf of Mexico, where shallower waters resulted in a massive, dense cloud of vaporized sulfur (as much as 100 billion tons worth) that wiped out the dinosaurs. As professor Ben Garrod, a co-presenter of “The Day the Dinosaurs Died” special, told the BBC, “it wasn’t the size of the asteroid, the scale of blast, or even its global reach that made dinosaurs extinct–it was where the impact happened.”

The resulting massive cloud blocked out the sun, leading to a dramatic cooling period, or “global winter,” which lasted for more than a decade and saw temperatures drop below the freezing level. As Garrod told the NY Post, “As the lights went out, global temperatures plunged more than 50 degrees Fahrenheit within days.”

Artist recreation of the asteroid that wiped out the dinosaurs
Artist recreation of the asteroid that wiped out the dinosaurs. (Credit: iStockphoto.com)

With nearly all vegetation and most animal life dead within months or a few years thanks to an endless grey sky, those dinosaurs who didn’t die in the immediate aftermath of the asteroid (or thanks to the resulting tsunamis and molten debris that fell from the sky) would have starved to death as their food sources disappeared. In all, it’s estimated that three-quarters of all life on Earth was destroyed.

Working at the Chicxulub crater, 24 miles off Mexico’s Yucatan Peninsula, scientists drilled a half-mile deep into gypsum-rich rock to examine the remnants of the asteroid, which left behind a gaping, 111-mile-wide by 20-mile-deep hole. They estimate that the asteroid was 9 miles wide, tiny in comparison to Earth (according to The Times, that’s like a grain of sand hitting a bowling ball), and traveling at 40,000 mph.

Its impact, reports Yahoo, contained the energy of 10 billion atomic bombs, causing a tower of matter taller than the Himalayas (and topping 18,000 degrees Fahrenheit) to shoot into the sky. Nearly everything within 600 miles would have been destroyed instantly, and significant damage has been detected in sites more than 1,600 miles away from the crater.

But while the asteroid’s timing spelled doom for the dinos, it opened the door for humans. The disappearance of these fearsome predators allowed for other animals, including our own mammal ancestors to thrive. As Alice Roberts, a scientist and co-presenter of the BBC special told The Times, “As the clouds started to clear a tiny group of animals came out of hiding to inherit Earth. With the dinosaurs gone, suddenly the landscape was empty of competitors and ripe with possibilities.”