Dinosaurs *were* wiped out by asteroid, scientists say - Image courtesy Wikimedia Commons

A review of all the evidence by a panel of scientific experts have come to the definitive conclusion that dinosaurs and half the species on earth were wiped out in the Cretaceous-Tertiary period by an asteroid.

Researchers from Imperial College, the Open University, the University of Cambridge and University College London looked at 20 years of research to come to their conclusion about the mass extinction, which happened 65 million years ago.

The panel of 41 experts said that the asteroid hit earth at Chixculub in Mexico. The experts say that the asteroid was about 15 kilometres wide, around the same size as the Isle of Wight, and travelling at the speed of a bullet created an explosion a billion times greater than the Hiroshima atom bomb.

Much of life on our planet were wiped out in just a few days, but the extinction paved the way for the rise of mammels on earth.

Scientists were divided previously about whether the extinction was caused by the asteroid crash or volcanoes in the the Deccan - those eruptions continued for an astonishing 1.5 million years.

The 41 boffins studied research from palaeontologists, geochemists, climate modellers, geophysicists and sedimentologists from the last 20 years.

They believe that the only reasonable explanation for rapid extinction is the impact of the Chicxulub asteroid. Even though volcanic activity lasted for a long period of time, it would not have caused fast rapid extinction.

Dr Joanna Morgan, who co-authored the review and works for Imperial's Department of Earth Science and Engineering, said: “We now have great confidence that an asteroid was the cause of the KT extinction. This triggered large-scale fires, earthquakes measuring more than 10 on the Richter scale, and continental landslides, which created tsunamis. However, the final nail in the coffin for the dinosaurs happened when blasted material was ejected at high velocity into the atmosphere. This shrouded the planet in darkness and caused a global winter, killing off many species that couldn’t adapt to this hellish environment.”

Her colleague, Dr Gareth Collins, said "While this hellish day signalled the end of the 160 million year reign of the dinosaurs, it turned out to be a great day for mammals." It paved the way for human beings to become the dominant species on the planet, he said. The article is published in Science.

There's some dino collateral here.