Was it so abrupt after all?
Researchers believe that the disappearance of dinosaurs took place around 65 million years ago. More than 1/3 of the world’s animal and plant species went extinct. What happened so many million years ago? We are not sure. Scientists after studying the soil, rocks and the fossils have concluded that something deadly and disastrous had occurred.

One of the most popular explanations for this catastrophe is that an asteroid or comet stuck this earth. The collision is assumed to have caused huge clouds of dust or sulphuric acid, which blocked sunlight and which led to global cooling. There must have been a very drastic change in the climate, which permitted only a few living organisms to survive.

There is a very thin layer of a rock with a rare property- the presence of the element iridium. Iridium is very rare on earth but not in asteroids or meteorites.

The other famous theory is that of "Mass extinction". The scientists believe that a million years ago as the global climate changed rapidly it caused the theory of mass extinction.

Some people believe that there must have been a variation in earth’s magnetic field or due to volcanoes.

It still remains a mystery.

A Dinosaur