Trending Science: So close! How the dinosaurs could have survived
An international team of scientists has argued that if the asteroid that likely caused the extinction of non-avian dinosaurs had hit the Earth only a minute or two earlier (or later), the extinction may never have taken place and, the dinosaurs might have survived, and us humans may never have existed.
The new theory, espoused by an international team of researchers from institutions including Imperial College, London, the University of Bremen and the University of Texas, completely flips on to its head the conventional belief that the demise of the dinosaurs was inevitable. The team outlined their argument in a documentary for the BBC, ‘The Day the Dinosaurs Died’ that was broadcast in the UK on 15 May.
So how is it possible that the ‘terrible lizards’ may have survived? Essentially, if the massive asteroid that ploughed into the shallow waters of what is now present-day Yucatan, Mexico, had instead crashed further out into the deeper Atlantic or Pacific Oceans, the impact would not have occurred in an area made up of limestone and rich in carbon dioxide, sulphur and deadly gypsum. Due to the Earth’s rotation, even a minute or two later or earlier could have made a world of difference to the dinosaurs’ fates.
‘When the asteroid hits with the force of something like 10 billion Hiroshima explosions, all of that gets pumped up in the atmosphere, and it may have been really critical for the mass extinction that followed as it blocked out the sun,’ commented Sean. P. Gulick, a University of Texas professor who studies catastrophism in the geological record. ‘A few minutes earlier or later and the asteroid would’ve hit the Atlantic or the Pacific Ocean and not slammed into a big, volatile platform that was then vaporised as it spread upward and outward.’
‘This is where we get to the great irony of the story – because in the end it wasn’t the size of the asteroid, the scale of the blast, or even its global reach that made dinosaurs extinct – it was where the impact happened,’ said one of the documentary’s BBC presenters, Ben Garrod.
So what would have happened if the killer asteroid had hit the deeper ocean instead of the shallows of the Yucatan peninsula? Indeed, an ocean impact would have caused a much less dense cloud and sunlight could still have reached the planet’s surface, ultimately meaning that the late-Cretaceous mass extinction of 75% of the world''s species may have been avoided.
Instead, by smashing into Yucatan, the research team argues through the documentary that the asteroid would have released a radioactive fireball that reached 18 000 degrees and scorched the Earth for 1 000 kilometres in every direction, as well as caused the largest tsunami in Earth’s history. A deadly vapour containing billions of tons of sulphates fanned out over the globe, completely blocking out all sunlight and lowering temperatures, casting the Earth in shadow. Molten material from the crater would have rained down for thousands of miles in every direction, starting fires and turning the atmosphere into an oven. With plant life being extinguished within days, the dinosaurs had no chance of survival.
To arrive at the conclusion that a deep ocean impact could have seen the dinosaurs survive the collision, the research team spent eight weeks in Yucatan, intensively drilling in the impact crater and removing samples that were then analysed at the University of Bremen, Germany. By analysing the 800 metres of rock collected, the team believes that they can now prove the asteroid was travelling at 65 000 kilometres per hour when it hit and unleashed its fury on the Earth.
However, the end of the dinosaurs in such catastrophic circumstances was a blessing in disguise for mammals, which had been, up until the late Cretaceous period, living in the dinosaurs’ shadows. Just half a million years after the great Cretaceous extinction, the world was dominated by mammals of all shapes and sizes, and ultimately led to the evolution of us humans.
So although it may be exciting to think about having less chickens and a few Velociraptors running around with us in the modern world (and Velociraptors were much smaller than popular culture has us believe, and so we wouldn’t have had to worry about them opening doors), from a mere human’s selfish point-of-view, it may ultimately have been a good thing that the asteroid hit the Earth exactly when and where it did on that fateful day 65 million years ago… We may never have existed otherwise…
last modification: 2017-05-29 17:15:02