why do dinosaurs died out 65 million years ago

The extinction of the dinosaurs is one of the most famous events in Earth's history, and it happened around 65 million years ago at the end of the Cretaceous period. While there are several theories, the most widely accepted explanation for this mass extinction event, known as the K-T (or K-Pg) event, involves:

1. Asteroid Impact: The dominant theory is that a massive asteroid, approximately 10 kilometers (6 miles) in diameter, collided with Earth. The impact site, known as the Chicxulub Crater, is located under the Yucatan Peninsula in present-day Mexico.

2. Volcanic Activity: Another contributing factor was increased volcanic activity, specifically the massive Deccan Traps eruptions in what is now India. These eruptions released enormous amounts of lava, ash, and gases over an extended period.

3. Environmental Changes: The combined effects of the asteroid impact and volcanic activity led to rapid and drastic environmental changes. These included:

   • Dust and Smoke: The impact and volcanic eruptions ejected massive amounts of dust and smoke into the atmosphere, blocking sunlight.
   • Climate Shift: The reduction in sunlight led to a significant drop in temperatures globally, affecting plant growth and food chains.
   • Acid Rain: The release of sulfur and other gases into the atmosphere could have caused acid rain, further damaging plant life and aquatic ecosystems.
   • Ocean Acidification: The additional carbon dioxide in the atmosphere could have led to ocean acidification, impacting marine life.

These combined factors would have drastically reduced the availability of food and habitats for many species, including the dinosaurs, which were unable to adapt or survive in the new environment. Smaller, more adaptable mammals, birds, and other organisms that could find food in the altered environment were more likely to survive.

It's important to note that not all species died out; some groups, such as crocodiles and turtles, which are also reptiles, survived and diversified. The extinction event paved the way for the rise of mammals, including eventually, humans.