The Asteroid Impact Theory
The asteroid impact theory proposes that an asteroid or comet about 6 miles wide crashed into Earth near what is now Chicxulub, Mexico, 66 million years ago. The impact would have created a crater about 100 miles wide and triggered a series of global catastrophes, including:
- A massive earthquake that would have caused widespread destruction and tsunamis that would have reached heights of over 100 feet
- A firestorm that would have burned everything within hundreds of miles of the impact site
- A global winter caused by the dust and debris that would have been thrown into the atmosphere, blocking out the sun and causing temperatures to drop by as much as 20 degrees Celsius (36 degrees Fahrenheit)
The asteroid impact theory is supported by a number of pieces of evidence, including:
- The presence of a large crater at Chicxulub, which is the same age as the dinosaur extinction
- The presence of a layer of sediment around the world that contains high levels of iridium, an element that is rare on Earth but common in asteroids
- The presence of fossilized plants and animals that show evidence of having been killed by a sudden, catastrophic event
The Volcanic Eruption Theory
The volcanic eruption theory proposes that massive volcanic eruptions in what is now India, known as the Deccan Traps, released large amounts of carbon dioxide and other greenhouse gases into the atmosphere, which caused global temperatures to rise. The rising temperatures would have disrupted the Earth's climate, leading to a series of changes that would have made it impossible for dinosaurs to survive.
The volcanic eruption theory is supported by a number of pieces of evidence, including:
- The presence of a large number of volcanic rocks in the Deccan Traps that are the same age as the dinosaur extinction
- The presence of evidence that the Deccan Traps released large amounts of carbon dioxide into the atmosphere
- The presence of fossilized plants and animals that show evidence of having been killed by a gradual, long-term event
Which Theory is Correct?
The evidence seems to support the asteroid impact theory more than the volcanic eruption theory. However, it is possible that both events played a role in the dinosaur extinction.
Conclusion
The debate over what killed the dinosaurs is a complex one, and there is still much that we do not know. However, the evidence seems to suggest that an asteroid impact was the main cause of the dinosaur extinction.
