The Extinction Event
A mountain-sized asteroid blasted into Earth 66 million years ago, close off the coast of Mexico’s Yucatán Peninsula, dooming dinosaurs and causing their extinction.
The collision was catastrophic, resulting in tsunamis that flooded large areas of shoreline and firestorms that raged over the world. The collision also hurled massive volumes of dust and vaporized rock into the air, blocking the sun for lengthy periods of time, along with soot from all those flames.
To make matters worse, most of the melted rock was Sulphur-rich, resulting in Sulphuric acid raining down on Earth and acidifying the oceans.
In an event known as the K-T mass extinction, these and other haymakers wiped out three-quarters of all species on Earth, including non-avian dinosaurs. Experts suggest extensive volcanism in Western India’s Decan Traps region and long-term climate change contributed to the slaughter. But, the cosmic impact was the final nail in the coffin.
The asteroid that caused this havoc is long gone, annihilated by its own kamikaze attack. Over the last few decades, scientists have been able to quantify it to some extent. Here’s all we know about the infamous dinosaur killer.
Searching for the Asteroid
66-million-year-old clays worldwide have considerably more of the rare metal iridium than the layers above and below them. After noting the same, team led by Nobel Prize-winning physicist Luis Alvarez suggested the death-by-above scenario for the K-T extinction in 1980.
According to scientists, the Iridium was likely supplied by an impactor that struck Earth at the time. A decade later, another study team discovered the impact site. It was a submerged crater spanning the Yucatán Peninsula and the Caribbean Sea and measuring 90 miles (150 kilometers) in diameter. Further research indicated that the crater, known as Chicxulub, developed 66 million years ago and that iridium levels appear to decline as the distance from the center increases.
Asteroid or Comet
What was the nature of the object that smashed into Earth 66 million years ago? The prevailing opinion is that it was an asteroid, as Alvarez and his colleagues suspected.
However, other geologists believe Chicxulub Crater was blasted away by a comet. Harvard astrophysicists Amir Siraj and Avi Loeb stated in a February 2021 study that comets are the best fit for the geochemical data, which shows that the impactor had a Carbonaceous Chondrite composition. Carbonaceous chondrites are a form of dark, primordial meteorite that, among other things, contains high quantities of carbon and minerals that have changed by water.
Siraj and Loeb also estimated that around one-fifth of all long-period comets – frozen wanderers with orbits lasting more than 200 years — break apart as they pass near the sun, resulting in many fragments.
We’re still not sure where the dinosaur-killing asteroid originated from; its parent body is unknown. However, research from 2021 narrows down the area where it was born.
SwRI scientists David Nesvorn, Bottke, and Simone Marchi published a report in which they utilized computer models to better comprehend the asteroid population and powerful impacts like the one that wiped out the K-T species. They discovered that the dinosaur killer was an asteroid that used to be in the main belt, likely in the far reaches.
Dark carbonaceous asteroids make up around half of all Earth-impacting objects larger than 3 miles (5 km), according to Nesvorn and his team. They also discovered that asteroids with a diameter of at least 6 miles only strike our planet once per 250 million to 500 million years. So, fingers crossed, another one won’t be coming our way for quite some time.
If you’re enthralled by the world of dinosaurs, then maybe you’d like to read about this place that would take you to a different: Red Wood National Park.