A major new inquest into the death of the dinosaurs has decided they really were wiped out by a giant asteroid up to ten miles wide.
It hit the Earth at 20 times the speed of a bullet killing off half of all species. The probe was the biggest ever held into the catastrophic event 65 million years ago.
A panel of 41 international experts, including scientists from four UK universities, re-examined 20 years of research into what is called the Cretaceous-Tertiary (KT) mass extinction.
They decided the overwhelming eveidence showed that a massive asteroid nearly 20 miles wide slammed into the Yucatan Peninsula, Mexico, at a spot called Chicxulub. This created an explosion with the force of one billion atomic bombs of the size that destroyed Hiroshima.
The blast sent a cloud of debris high into the atmosphere, blocking out sunlight and triggering a global winter that wiped out much of life on Earth in a matter of days. Dinosaurs, bird-like pterosaurs and large marine reptiles were killed off.
There has previously been much controversy over whether a space missile did for the dinosaurs or whether a series of super volcano eruptions in the Decan Traps, in India, lasting one and a half million years might be to blame.
Those eruptions were thought to have cooled the stmosphere and produced acid rain on a global scale.
The new inquest, reported in the hournal Science, decided that the speed at which life at sea and on land was destroyed meant that only the asteroid impact could have caused it.
Dr Joanna Morgan, of Imperial College London, 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.”
Colleague Dr Gareth Collins, of Imperial College London, said: “The explosion of hot rock and gas would have looked like a huge ball of fire on the horizon, grilling any living creature in the immediate vicinity that couldn’t find shelter.
“Ironically, 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, who had lived in the shadow of the dinosaurs prior to this event. 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.”
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