I think all craters are cool, I’m just going to start with that. I am very biased.
Impact craters occur on every planetary body in our solar system, no matter the size. By studying impact craters and the meteorites that cause them, we can learn about the processes and the geology that shape our entire solar system.
This list contains some of my favorite impact craters down here on Earth.
- Meteor Crater, AZ, US
The one that started it all.
Barringer Crater (often called Meteor Crater), is located near the city of Winslow on Route 66 in Arizona, US, and was the first crater confirmed to have been caused by an extraterrestrial impact.
Meteor Crater is about 1km in diameter and roughly 50,000 years old, making it relatively “young”. We’ve known about the crater since the late 19th century, but there was debate as to whether it was from an impact, or associated with the nearby volcanic province.
It wasn’t until the 1960s when high-pressure forms of quartz were identified in the rocks, together with meteorite fragments found nearby, that scientists could conclusively say it was a meteorite impact.
The crater is a site of active research. It is very well preserved, making it an excellent place to learn about the process of impact cratering. Since the early Apollo days, Meteor Crater has also been used to train astronauts. The practice continues to this day, with Artemis astronauts learning how to navigate terrains like those they will encounter on the lunar surface, as well as a bit of geology.
Today you can visit the crater (the gift shop is excellent!) and take a tour around the rim. It is a great addition to any trip to the Grand Canyon.
- Chicxulub, Yucatán, Mexico
The dinosaur killer!
Possibly the best-known meteorite impact on Earth is the one that left the largely buried Chicxulub impact structure on the Yucatán peninsula in Mexico. This 180km diameter crater is the second largest on Earth and has been dated to 66 million years ago—coincidental with the extinction of the dinosaurs.
For years geologists had searched for a mass extinction recorded in rocks around the world. It wasn’t until the discovery of iridium, an element much more abundant in meteorites than on Earth, that the pieces fell into place.
The object that impacted Earth is estimated to have been 10km in diameter, traveling at 20km/s. That’s about 5 minutes to travel from Sydney to Los Angeles.
It wasn’t just the dinosaurs that became extinct though—it is estimated that 75% of the plant and animal species on Earth became extinct as a result of this event.
The impact would have been immediately catastrophic, with aftereffects felt for decades. There were large tsunamis, and forests burned around the world. Sunlight would have been obliterated by ash and gases, possibly for years, triggering a global winter where many more species perished.
Eventually, though, the crater system became a flourishing deep biosphere as the planet repopulated at the end of that long winter.