The end of Dinosaurs! Dinosaur extinction

There are many theories trying to explain the disappearance of dinosaurs. The most widely accepted one today is the theory proposed by the Nobel prize-winning physicist Luis Alvarez and his son geologist Walter Alvarez. It assumes that the mass extinction of dinosaurs was caused by the impact of a large asteroid on the Earth sixty-five million years ago.

The father-and-son scholarly team first suggested this back in 1980, and in 2010, based on evidence discovered in the meantime, an international panel of scientists endorsed the asteroid hypothesis. They determined that a 10-15 km wide space rock hurtled into earth, and that the collision released the energy equivalent to 100 million megatons of TNT, over a billion times the energy of the atomic bombs dropped on Hiroshima and Nagasaki.

The impact penetrated the Earth's crust, scattering dust and debris into the atmosphere, causing huge fires, increasing already active volcanic eruptions, triggering tsunamis and severe storms with high winds and acid rains. All this produced chemical changes in the atmosphere, increasing concentration of sulphuric acid, nitric acid, and fluoride compounds. A vast dust cloud blocked sunlight and prevented photosynthesis for several years. This accounted for the extinction of plants and phytoplankton, and all herbivorous dinosaurs starved to death. Eventually, at the top of the food chain, meat-eating dinosaurs were left with nothing to eat either. Thus, all types of dinosaurs vanished from the face of the Earth, except one branch which over time has evolved into modern birds.

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