Researchers from Vrije Universiteit Brussel in Belgium have identified the culprit behind the dinosaur extinction: a colossal asteroid impact about 65 million years ago that blanketed the atmosphere with dust and triggered a prolonged winter. The findings, published in Natural Geology, confirm the long-standing idea that reduced sunlight from atmospheric dust played a key role in wiping out the dinosaurs. The study underscores how the aftereffects of that impact altered climate and photosynthesis on a global scale, contributing to the mass extinction event that ended the Cretaceous period.
Over recent years, some scientists proposed alternative explanations suggesting sulfur-rich fumes or soot from vast forest fires might have produced the cooling effect. They argued that the dust particles could be too large to linger in the atmosphere for an extended period, challenging the dust-dominant extinction scenario.
In a new line of investigation, researchers directly measured the dust particles formed immediately following the asteroid strike. The team examined ancient lake sediments from the Tanis site in North Dakota, where microfossils and other geological clues capture the immediate aftermath of the event. The particles ranged in size from about 0.8 to 8 micrometers, a range compatible with aerosols capable of scattering sunlight and cooling surface temperatures for years to come.
According to climate modeling, the persistent fine silicate dust remained in the atmosphere for roughly 15 years, driving a significant global cooling of several degrees. The models indicate that this dust would have reduced photosynthetic activity for at least a year, setting off a cascade of ecological disruptions. This sequence of atmospheric and ecological changes aligns with the fossil record, consolidating the view that particulate dust was a major driver of the mass extinction.
Meanwhile, new fossil discoveries in Australia have offered tantalizing glimpses into prehistoric life. Paleontologists describe the fossilized remains of a giant spider that once inhabited lush rainforests in the region. The specimen, provisionally named Megamonodontium mccluskyi, is estimated to be between 11 and 16 million years old. The discovery adds a rich thread to the story of ancient ecosystems, illustrating how diverse life forms adapted to evolving climates over deep time.
In other historical notes, environmental activists previously triggered controversy at the Museum of London by spraying starch onto a dinosaur skeleton. The incident sparked discussions about how natural history artifacts are displayed and protected, highlighting the balance between public engagement and conservation in museum settings.