The Last Day of Dinosaurs on Earth

The extinction of the dinosaurs is a topic that has fascinated scientists for many years. The leading scientific consensus is that dinosaurs, along with many other species, went extinct around 65 million years ago at the end of the Cretaceous period. The most widely accepted hypothesis for this mass extinction event is the impact hypothesis, which suggests that a massive asteroid or comet impact played a significant role.

The key points of the impact hypothesis are:

Impact Event: A large asteroid or comet, estimated to be about 10 kilometers in diameter, struck the Earth near the present-day Yucatan Peninsula in Mexico.

Environmental Effects: The impact would have caused massive fires, triggered earthquakes, and released a tremendous amount of energy. Additionally, it would have thrown large amounts of dust, debris, and vaporized rock into the atmosphere.

Climate Change: The material ejected into the atmosphere would have blocked sunlight, leading to a "nuclear winter" effect. This dramatic climate change would have disrupted ecosystems and led to a significant drop in temperatures worldwide.

Impact on Photosynthesis: The reduction in sunlight reaching the Earth's surface would have severely impacted photosynthesis, disrupting the food chain and causing a collapse of ecosystems.

Global Extinction: The combination of these effects, along with other contributing factors like volcanic activity, is believed to have led to the mass extinction event, wiping out approximately 75% of Earth's species, including the non-avian dinosaurs.

While the impact hypothesis is widely supported, some scientists also suggest that other factors, such as volcanic activity, may have played a role in the extinction. Regardless, the asteroid impact is considered a major contributing factor in the catastrophic environmental changes that led to the demise of the dinosaurs and the beginning of the Cenozoic era, during which mammals diversified and became the dominant land animals.