After years of theories and debates, a panel of 41 scientists from around the world sat down and pawed over 20 years worth of research material. Their conclusion? An asteroid is the only plausible explanation for the extinction of dinosaurs.

The panel analyzed the work of paleontologists, geochemists, climate modelers, geophysiscists and sedimentologists who have been collecting evidence about the KT extinction for the last 20 years.

The scientists from the U.S., Europe, Canada, Mexico and Japan determined that a 9 mile (15 kilometers) wide asteroid caused the Cretaceous-Tertiary (KT) extinction. The asteroid is thought to have hit Earth with a force a BILLION times more powerful than the atomic bomb at Hiroshima, setting off fires, earthquakes, landslides, and tsunamis. The blast encased the Earth in darkness causing a global winter, in turn destroying land and marine ecosystems which killed off mass amounts of species.

The cause of the extinction of the dinosaurs had been narrowed down to two possible causes, an asteroid, and volcanic activity in the Deccan Flats (around India) where a series of super volcanic eruptions lasted around 1.5 million years.

The Deccan Flats volcano theory was thrown out when models of atmospheric chemistry showed the asteroid impact would have released much larger amounts of sulphur, dust and soot in a much shorter time than the volcanic eruptions.  These were more consistent with the extreme darkening and cooling that occurred.

According to Gareth Collins, co-author from Imperial College, “The KT extinction was a pivotal moment in Earth’s history, which ultimately paved the way for humans to become the dominant species on Earth.”

Thanks dinosaurs.

If you’d like to get a visual of what the impact may have been like you can visit this 3D model (using Google Earth) http://impact.ese.ic.ac.uk/ImpactEffects/Chicxulub.html