Why is iridium linked to the extinction of dinosaurs?

One of the most puzzling questions in science is about the extinction of dinosaurs. The most accepted answers for this puzzle points at the ‘asteroid disaster’ theory according to which a huge asteroid struck the Earth’s surface about 65 million years ago.

The exploding asteroid threw enormous amounts of dust into the air that blocked sunlight for more than a year. As a result, plants on the Earth’s surface died; the dinosaurs that lived on those plants as well as and the meat-eating dinosaurs that lived off the plant eaters, died.

But, how is it possible to know if an asteroid really did hit the Earth’s surface 65 million years ago? Scientists today have an answer to this. They have found a layer of the Earth’s crust that contains an unusually high level of iridium metal.

Iridium rarely occurs on Earth. But it occurs much more commonly in meteors and asteroids. Scientists believe the iridium-rich layer was formed when the asteroid struck the Earth’s surface. This ‘iridium clue’ is a key, therefore, to understanding how dinosaurs disappeared from the Earth.

Picture Credit : Google