A large asteroid that hit Earth near Mexico’s Yucatán Peninsula 66 million years ago led to a global winter causing the mass extinction of dinosaurs. The asteroid didn’t kill all the dinosaurs instantly, but triggered a gradual extinction of species. Scientists generally agree that the Chicxulub impact wiped out 75% of all species on Earth, but the exact cause of the drastic climate shift following the event has been uncertain. Recent research suggests that the cause was fine dust particles that were blasted into the atmosphere due to the impact. This layer of dust blanketed Earth for up to 20 years, causing the most severe conditions in the first five to eight years.
In the first year after the impact, global temperatures dropped by more than 10 degrees Celsius. Previous research focused on soot and sulfur, which absorb and block sunlight more effectively than dust, as the main contributors to the long, dark winter. However, a 66-million-year-old rock sample collected in North Dakota shows a lot more fine dust particles than expected, indicating dust played a bigger role in the event than previously thought.
Researchers used the data from the rock sample to simulate post-impact climate. The simulation predicted a blanket of dust particles between 0.8 and 8 micrometers in diameter formed just a week after impact. Within two weeks, this blanket, which researchers suspect hovered in Earth’s atmosphere longer than soot and sulfur, stopped plants from photosynthesizing for up to two years, leading to the starvation of species relying on them, including non-avian dinosaurs.
The new study highlights the overlooked role of dust particles in the global impact winter. However, it’s unlikely to be the final word on whether soot or dust caused the cooling, as variations in climate models could lead to different results. The study explains how hibernating plants and animals could have survived the two-year-period without photosynthesis, but it doesn’t explain how freshwater organisms survived the impact. Therefore, more research is needed to better understand the “exact killing mechanisms” after the Chicxulub impact.
Key Takeaways:
- The asteroid that hit Earth 66 million years ago near Mexico’s Yucatán Peninsula caused a global winter that led to the mass extinction of dinosaurs, who had dominated the planet for over 160 million years.
- The drastic climate change following the asteroid impact was likely due to fine dust particles that were blasted into the atmosphere, creating a layer of dust that covered the Earth for up to 20 years, with the first five to eight years being the most severe.
- The dust particles, which were larger in quantity than previously thought, blocked sunlight and stopped plants from photosynthesizing for up to two years, leading to the starvation of species that relied on them, including non-avian dinosaurs.
“66 million years ago, a large asteroid crashed into Earth near Mexico’s Yucatán Peninsula, sparking a frigid global winter that led to the mass extinction of dinosaurs who had reigned over the planet for over 160 million years.”
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