The ice age? Super volcanoes? A cluster of giant asteroids? Fred Flintstone working them to the bone for a series of suspiciously 20th century looking contraptions?
While there’s no end to the theories of what wiped the dinosaurs out - including the most commonly held culprit, Mexico’s 66-million-year-old Chicxulub impact crater, suspected bolide impact site - a maverick new premise has emerged with potential evidence to boot.
Published in the journal Gondwana Research, a team led by the Japan Spaceguard Association claim Earth may have passed through a dense interstellar cloud just before the creatures went extinct, causing a Nebula Winter which in turn brought about a large amount of global cooling, eventually destroying most of life on the planet.
Earth, you see, is covered by an iridium, a substance thought to be extra-terrestrial in origin, 12-inches thick and the work of asteroid impacts. Well this team, led by Tokuhiro Nimura, found a substantially thicker deposit of iridium in the Pacific Ocean – 16ft thick in fact - which they say can’t be explained by an asteroid.
As an alternative, the team wrote that a molecular cloud 330 light-years across, and more than a thousand times denser than the surrounding space, is the reason why these majestic creatures met their sticky end.
Not that the creatures' end came straight away, as it would have done following any major asteroid apocalypse. The report adds that it might have taken a million years for earth to pass through the cloud, darkening the sky bit by bit and ultimately suffocating all life, with earth picking up this iridium passing through the cloud.
“The dark cloud would have caused global climate cooling in the last 8 million years of the Cretaceous period,” the report read. “The resulting growth of the continental ice sheet also resulted in a regression of the sea level. The global cooling, which appears to be associated with a decrease in the diversity of fossils, eventually led to the mass extinction."
Whatever the answer, the fact prehistoric discoveries could be further strengthened by finding other radioactive elements that may have originated from space such as plutonium on the sea floor could be a game-changer going ahead.
Just as long as it doesn’t affect the sequel to Jurassic World, we’re happy.