Chicxulub

What do dinosaurs and astronomy have in common? Turns out a lot more than we once thought.

Dinosaurs roamed the Earth for about 165 million years. They were considered among the most superior species to wander the planet. Their size and ferocity allowed them to roam and dominate as they saw fit. We as humans by comparison have only been on the planet about 2 million years. And even of that, we have only been living in organized relationships called society for about 15,000 years.

An unforeseen and unpreventable event took place 65 million years ago that somehow changed the course of evolution and allowed the mammals to ascend and eventually us. That change was a huge impact from a piece of space debris, somewhere between 6 and 15 km in diameter and traveling at some 20 km/second slamming into the planet.

For many years scientists were aware of the time of the extinction of the dinosaurs. They also were aware of a layer of iridium embedded in the soil corresponding with the time of the end of the dinosaurs, all found at the K-T boundary (or K-Pg), AKA the Cretacous-Paleogene boundary point. What they lacked was an explanation.

As it turns out, the best source for Iridium is space. Very little is found on Earth but it is chiefly found in meteorite debris. Using reasoning, scientists concluded that some sort of extraterrestrial event must have taken place to cause this mass extinction, and the logical answer was a meteor impact.

What they lacked was evidence, and a crater. Until 1978, that is, when during an oil exploration search in the Yucatan Peninsula, geologists unearthed a massive crater with the center of it in the water, and some 180 km in diameter. They had located the smoking gun, and the age coincided with the disappearnace of the dinosaurs from the scene. Work continues to understand this even today.

For those unaware, this was a major event. The debris kicked up from this impact exposed the earth’s mantle, resulting in the release of molten lava, dust, debris that circled the planet, with winds in excess of 1000 km/hr generated, major tsunamis, and it created fires and the blocking of the sunlight sent the world into a form of nuclear winter, quickly killing off all food sources for the major predators and wiping out about 75% of all life on the planet.

Pretty humbling to say the least. It killed off all the largest earth bound dinosaurs except the avian dinosaurs that evolved into birds. The birds continued to thrive and diversify as did many smaller mammals and rodents, where their distinct evolutionary advantage of size and food requirements allowed them to scavenge through hard times and survive. Within 30,000 years, the planet had healed, and many ecosystems were again thriving. Some of that transition involve dominant species being survivors and then adjusting to a new normal. This is what the Earth does.

The lesson to learn from the dinosaurs is simple. All life is vulnerable. Complexity and dominance are no guarantees of survival. And even when the biggest and most deadly are wiped out, the planet adapts and changes. And whether we recognize it or not, we are next on that list.