Mass Extinction: A Closer Look At What Killed The Dinosaurs

In his book titled “T. Rex and the Crater of Doom”, Walter Alvarez lays out his expertly developed theory on how the demise of the the dinosaurs was caused by an object believed to be an asteroid or a comet colliding with the Earth at the Yucatan Peninsula leading to a mass extinction. Alvarez describes the key differences between two theories. One being catastrophism, in which early scientists believed the earth evolved due to a large catastrophic event because of the amount of time Biblically allotted for the formation of landmarks such as mountains was so small that there was no other way to explain it. The second theory being gradualism, otherwise referred to as uniformitarianism, in which scientists learned that the Earth actually evolved over billions of years due to both natural processes such as erosion, and more recently, human activities. He then goes on to explain the excessive amounts of iridium him and his colleagues found in the rocks at the K-T boundary and why this matters. The high amount of iridium was found only in rocks at the boundary and nowhere else, and the iridium was about the same amount that we would expect to find in a meteor, indicating that these rocks were pieces of debris which resulted from something very large hitting the Earth. He describes the thought processes of him and his colleagues in coming to this conclusion in the 1970s, as well as how their ideas may have evolved along the way as new discoveries were made, either proving or disproving their hypotheses. Alvarez does this in an engaging way using anecdotes from him travels with his father in search of evidence of this crater, now known as the Chicxulub Crater, in order to effectively inform any reader, even those who may not necessarily be scientifically inclined.

The theme that I have chosen to focus on is perhaps the central idea which is the mass extinction that ended the dinosaurs, and how it came to be. It is interesting to think of a world different than the one we know, a world, similar to ours, in which we still have mountains, swamps, forests, and oceans, but one with animals we have never seen, roaming around on grassless fields. A world which existed 65 million years ago at the end of the cretaceous period of the Mesozoic Era. It is not at all unreasonable suspect that, had the world remained undisturbed, this would still be the world today. However, this world did not remain undisturbed. In fact, it ended quite abruptly 65 million years ago, wiping out entire plant and animal species in a mass extinction caused by what's known as the K-T impact.

According to Alvarez, the best way for us to comprehend the full impact of the comet or asteroid that hit the Earth 65 million years ago, is to make analogies to understand not only the size of the object, but also the velocity at which it was traveling which is what made it truly catastrophic. The object was about 10 km in diameter, meaning that if we were to place it on the Earth gently, it would be about 1 km taller than Mount Everest. If we were to measure this object in terms of volume it would be more voluminous than all the buildings in the United States together. To really understand the damage caused by this object, we need to understand how fast it was going as it was hurtling toward the Earth. Geologists have estimated that the object's velocity at the time of impact was 30 km per second making it 1000 times faster than a car driving down the highway and 150 times faster than a jet plane. When something travels this fast, it produces what's known as a shock wave. When a shock wave occurs, the impactor and the target rock are compressed so much that once the shock has passed, the rock that is decompressing will either melt, fly apart, or it may vaporize, which gives us an idea of how violent and destructive this event was.

This information, along with how it was acquired is essential to understanding the way that science evolves. The way that we understand the world today is drastically different from the way we saw it even just 50 years ago. One of the most astonishing things about this discovery is that it was made in the 1970s which seems like not that long ago. In fact, Walter Alvarez is still alive today. A true testament to the truly amazing way that science works. It excites me to imagine what other types of scientific breakthroughs will be made just in the time that I am alive. Having the knowledge that we now have, has provided us with the ability to study many different areas that we may not have been able to study without the understanding of what happened to the dinosaurs. For example, the discovery of the K-T extinction may have provided some key insight such as locations to geologists today who continue to search for fossils. The continued search for fossils is important today because it helps us to understand the evolution of species at the top of the land’s ecosystems from the beginning and up until now, rather than only seeing snapshots of their existence based on information gathered from living animals. We also need these fossil records in order to understand the rates of extinction and levels of diversity associated with certain species and how they hay have shifted as time went by. It also helps us to study how life managed to recover after a period of mass extinction and how certain conditions affect an ecosystem's ability to function. Having a better understanding of how the dinosaurs lived, why and how they died may guide us in understanding these, and many other aspects about life today.

Walter Alvarez, through his writing, perfectly epitomizes the purpose of science which is ultimately the search for truth. Despite the many setbacks he and his fellow scientists faced, whether it be in experimental mistakes, feuds with colleagues, or discoveries made entirely by accident, Alvarez and his colleagues preserved which demonstrated not only the hard work, patience and passion that goes into each scientific breakthrough, but also the importance of collaboration, constructive debate, and a willingness to be wrong in making discoveries that change the way perceive the world and how we approach science.