{"id":35357,"date":"2023-10-30T17:00:00","date_gmt":"2023-10-30T16:00:00","guid":{"rendered":"http:\/\/43f30bc8-0333-465a-a58a-fac3291c3922"},"modified":"2023-10-30T17:47:45","modified_gmt":"2023-10-30T16:47:45","slug":"a-giant-asteroid-explosion-didnt-kill-off-the-dinosaurs-dust-did","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/rss_feed\/a-giant-asteroid-explosion-didnt-kill-off-the-dinosaurs-dust-did\/","title":{"rendered":"A giant asteroid explosion didn\u2019t kill off the dinosaurs. Dust did"},"content":{"rendered":"

New research suggests dust in Earth\u2019s atmosphere was a leading cause of a mass extinction 66 million years ago. <\/p>

By Thomas Ling\n <\/p>

Published: Monday, 30 October 2023 at 16:00 PM<\/p>

\n\n

What killed the dinosaurs<\/a>? According to a recent breakthrough study, not a giant meteor impact.<\/p>

Well, at least not the impact itself. Although the 10km wide Chicxulub asteroid exploded into Earth with more energy than a billion nuclear bombs put together, it was the dust the collision kicked up into Earth\u2019s atmosphere that triggered the dinosaur\u2019s demise 66 million years ago.<\/p>

That\u2019s according to a new study, published in the journal Nature<\/em>, which suggests it was fine silicate dust produced by pulverised rock that sparked a dramatic period of global cooling<\/a>.<\/p>

\u201cThe explosion wasn\u2019t really what doomed the dinosaurs and all the other species that died,\u201d palaeontologist Prof Stephen Brusatte<\/a>, who was not involved, explained to BBC Science Focus<\/em>.<\/p>

\u201cThe dust and soot that went up into the atmosphere put the Earth into a deep chill, and blocked out the Sun<\/a> for at least a couple of years, and with plants unable to photosynthesise, ecosystems would have collapsed like houses of cards. It was probably these tiniest dust particles that had one of the greatest killing effects on life.\u201d<\/p>

It was previously thought that sulphur released from Chicxulub\u2019s impact, and the soot created from post-impact wildfires, were the main drivers of Earth\u2019s drastic cooling. However, various climate simulations used by a team of scientists from the Royal Observatory of Belgium indicate fine dust played a key role.<\/p>

When examining rock materials from Tanis \u2013 a well-preserved fossil site in North Dakota, US, well-known for providing direct evidence of the Chicxulub impact \u2013 the scientists found a much higher distribution of fine silicate debris less than 8 micrometres (0.000008m<\/em>) across than expected.<\/p>

Using data from the site, the researchers estimate the dust could have remained in Earth\u2019s atmosphere for 15 years after the asteroid impact, contributing to a 15\u00b0C drop in surface temperature.<\/p>

According to the new simulations, dust \u2013 alongside soot and sulphur \u2013 would have blocked plants from photosynthesising for two years, as well as triggering a chain reaction of animal extinctions.<\/p>

In total, the dinosaurs roamed Earth for approximately 165 million years (in comparison, Homo sapiens<\/em> have only existed for 300,000 years). The Chicxulub asteroid and its aftereffects killed off an estimated 75 per cent of life forms on the planet, including nearly all non-flying dinosaurs and large mammals.<\/p>

After the mass extinction, life continued in the form of small avian dinosaurs and mammals, many of which would eventually evolve into Earth\u2019s current life forms.<\/p>

About our expert<\/strong><\/h2>

Steve Brusatte is a professor of palaeontology at the University of Edinburgh who specialises in the anatomy, genealogy, and evolution of dinosaurs. He served as the dinosaur consultant in the film Jurassic World:<\/em> Dominion<\/em>, as well as BBC’s Walking with Dinosaurs<\/em>. His research has been published in journals including Nature<\/em>, Ecology and Evolution<\/em>, and Current Biology.<\/em><\/p>

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