How can one discovery change how we understand an event that occurred 66 million years ago? Read how a recent discovery altered our understanding about the day the dinosaurs died.
Could you imagine believing something your whole life and then you discover one little thing, and it changes everything? Everything you thought was knew and suddenly everything you learned in school being possibly wrong? It’s weird to think one small discovery can change everything. Well, history is funny like that. What we may have thought to have known on a specific event can be changed with the discovery of as something as small as a pebble, literally. History has no time limit, it can always be changing, even if it occurred 66 million years ago. 66 million years ago? The end of the dinosaurs.
I am assuming everyone here was taught about the meteorite that struck earth and killed the dinosaurs? If not, here’s a crash course. 66 million years ago a massive meteorite entered the earth atmosphere and struck Mexico. This meteorite marked the end of the cretaceous period as all dinosaurs went extinct. The belief was that when the meteorite hit the earth went cold. Cold, dark and death came slowly. It was believed due to the size of the meteorite and the speed it was travelling when it hit the earth, an enormous amount of dust was lifted and entered the atmosphere. The dust that was in the atmosphere was enough to create a sort of blanket around the entire world. The blanket created was also thick enough to block sunlight from reaching land and thus turned the earth cold. The lack of sunlight destroyed the dinosaur’s food chain. First small animals and plants will get sick, and die followed by bigger animals and eventually left the dinosaurs with no food. The extinction of dinosaurs took almost a million years to occur and eventually the last dinosaur died a slow and cold death.
Remember being told this story while in school? I remember. The thing about history is that even the smallest bit of new information can change the story drastically. This is exactly what happened to the story of the dinosaur’s extinction. Remember that pebble I told you about at the beginning? Well, this pebble like object changed the timeline of the extinction, how quick it occurred and the order in which life on the planet died. The extinction of the dinosaur’s has been a heavily debated topic and continues to be heavily researched by both scientists and archeologists. Every bit of evidence found can make all the difference and that is exactly what occurred less than ten years ago.
Now it is no mistake the asteroid that hit earth cause massive amount of damage. The asteroid was predicted to be around six miles wide and six miles long, travelling at a speed of 200,000 miles per hour. A massive rock hitting the earth at that speed with no doubt send a massive layer of dust into the atmosphere but that wasn’t the only matter sent up there. On a warm June or July day 66 million years ago, the earth was hit with a rock travelling so fast its impact measured to about 100 million mega tonnes (for reference, Hiroshima is calculated to be approximately 1.2 mega tonnes).
Now a couple things happen when a solid force hits the earth that strongly. First begin the dispersion of force, also known as a shockwave. When the asteroid hit, it created a 200 km crater and sunk 40 km into the earths surface. The energy created by this displacement led to numerous, powerful earthquakes and tsunamis around Mexico. These disasters are enough to destroy both life on land and in water. Powerful enough to kill dinosaurs. If you are like me, right about now you will probably be thinking “what about the dinosaurs on the other side of the globe?” Dinosaurs were not huddled in one spot; they were around the entire world and the tsunami and earthquakes would have been felt there. So, how did ALL dinosaurs go extinct? That brings me to the second thing that happens when an asteroid of that size hits the earth.
Have you ever dropped anything on the ground? And I mean anything. A ball, a pen or a phone (I know we’ve all done that). What happens to it though when you drop it from a great height? It bounces back up. This is no different from the asteroid, even if it’s a rock the size of Manhattan travelling faster than the speed of sound. The only difference between this rock and your phone is it is not the rock that bounces back up. Have I confused you yet? Scientists have performed many experiments trying to understand what happened the day the dinosaurs died and have determined that when the asteroid entered the earth’s surface, the center of the asteroid heated up to approximately 20,000 degrees.
Now here’s the interesting part. Any object that experiences that amount of heat in such a short period of time disintegrates. So, when the asteroid hit, it did not stay as a solid but rather turned into a high-pressured gas therefore when the bounce back effect occurred, it was not the asteroid itself that was sent back into the sky but rather this extremely hot gas. Now, let’s go back to you dropping your phone. You drop your phone out if your pocket, it may bounce up only a few inches but drop your phone off a roof? It bounces up higher. More speed means more height. So, back to the asteroid, a rock travelling from space enters and hits the earth at 200,000 mph, how high does it bounce up? To put it simply, a lot. It bounces up enough to send this hot gas back into space.
Space is cold and when the gas enters it, the gas begins to cool and when it cools it freezes all its heat inside some millions of tiny glass balls, the size of a pebble. These pebbles than drift apart and surround the entire globe. Unfortunately, the gas did not have enough speed to exit earth’s entire atmosphere and eventually 90% of them drift back into earth’s gravity force, making these glass balls fall back to earth but this time, everywhere. Just like the asteroid, these balls are picking up speed as it travels back to the ground but due to their size, they burn up quicker and higher up from the ground.
The gas trapped inside these glass balls were released and gave off a massive amount of heat. It is predicted the temperature across the globe quickly rose and hit 1200 degrees. 1200 degrees. Dinosaurs, plants, any living thing above the ground, sea animal above 300 feet and anything above three inches in the earth died in only two hours. In two hours, this asteroid wiped out approximately 76% of the earth’s living species. The evidence for this new theory?
In archeological dig sites you can see the layers of the earth and each layer has its own story. If you look deep enough down there you would see this small, thin line that looks different from the rock above and below it. You probably have already guessed it, but this line is located at the 66-million-year mark and represents the day the asteroid hit. This line is known as the K-T Boundary. Currently, all dinosaur fossils that have been discovered were found below this boundary and none have been discovered above it. From this, scientists have deduced that dinosaurs did not die slowly for a million years and died the day the asteroid hit, because at the most, this line represents only 100,000 years. This glass ball theory emerged after scientists studied the material within the K-T Boundary and found more of these balls buried in the dirt.
This new theory has changed history and our way of understanding the asteroid but who knows how long until this theory begins to be challenged with the discovery of new information. See, history is funny like that. The smallest discovery can change the entire timeline of an event. History has no timeline. In 100 years, archeologists could discover a dinosaur tooth above the K-T Boundary, and this will once again drastically change our understanding. For me, this uncertainty and the idea any day history can be changed is what I feel is the most interesting about it.