Here's a brief overview of the impact theory:
1. Asteroid or Comet Impact: Approximately 66 million years ago, an asteroid or comet measuring about 10-15 kilometers in diameter struck Earth near what is now the Yucatan Peninsula in Mexico. The impact site is marked by the Chicxulub crater, which is about 180 kilometers in diameter.
2. Crater Formation: The impact created a massive crater and released an enormous amount of energy, equivalent to billions of nuclear bombs. It caused ground shaking, tsunamis, wildfires, and dust clouds.
3. Global Consequences: The impact threw debris into the atmosphere, forming a dust cloud that blocked sunlight and led to a global winter. The drop in temperature caused a reduction in photosynthesis and disrupted the food chain. The dust also hindered sunlight penetration into oceans, affecting marine ecosystems.
4. Extinction: Many plant and animal species could not adapt to the rapid environmental changes caused by the impact. Over a short geological period, the dinosaurs, along with many other species, went extinct. It's estimated that about 75% of all plant and animal species on Earth disappeared.
5. Survival of Some Species: While the extinction event was catastrophic, some species managed to survive. These included small mammals, birds (descended from dinosaurs), a few reptiles, amphibians, and insects. The diverse bird population at the time, including early ancestors of modern birds, allowed birds to quickly diversify and fill various ecological niches left vacant by the extinction of the dinosaurs.
It's important to note that the impact theory is widely supported by scientific evidence, but there are other hypotheses and theories that have been proposed. Nonetheless, the impact theory remains the most accepted explanation for the mass extinction event that wiped out the dinosaurs.
