It has been a widely accepted theory that an asteroid caused the extinction of dinosaurs 66 million years ago.
But the question has always remained: how exactly did the asteroid wipe out most of life on earth?
Researchers at Tohoku University in Japan say they've found an explanation to why dinosaurs were wiped out, but other ancient animals lived on.
The theory, which was a joint study by the university and the Japan Meteorological Agency's Meteorological Research Institute, concluded that aerosol-soot in the air caused by the asteroid led to major climate changes which in turn led to the mass extinction of life 66 million years ago.
The team, led by Tohoku University Professor Kunio Kaiho, conducted the study by examining earth samples from Haiti and Spain - somewhere close to the crater of the asteroid, also known as the Chicxulub impactor, and somewhere far.