A massive asteroid – known as Nadir – struck the Earth around 66 million years ago, and not only blocked sunlight but also ‘wiped out’ nearly half of species on the planet, including dinosaurs, according to scientists.
In 1980, Nobel Prize winner physicist Luis Walter Alvarez, along with his son geologist Walter Alvarez, proposed a groundbreaking theory about the extinction event. They discovered unusually high concentrations of the element irdium in a layer of sediment dating to that period.
While iridium is naturally present on Earth, it is rare in the Earth’s crust and more common in extraterrestrial objects like asteroids. The Alvarez hypothesis suggested that when the asteroid struck the Earth, it deposited an unusually large amount of iridium, along with ejecting vast quantities of rock and debris into the atmosphere.
The debris in the atmosphere caused catastrophic climate changes, which led to the extinction of dinosaurs and many other species. Dr Uisdean Nicholson from the Heriot-Watt University first discovered the ‘Nadir’ asteroid in 2022, but a shadow of doubt about how it all happened never left his mind.
Along with his team, Dr Uisdean Nicholson discovered that there was another smaller asteroid that struck the Earth around the same time as the Cretaceous-Paleogene event, located off the coast of West Africa. This smaller asteroid, approximately five miles wide, was discovered nearly 1,000 feet beneath the Atlantic Ocean’s floor.
This research, led by Dr Uisdean Nicholson, used three dimensional (3D) seismic data to confirm that the crater was caused by the impact of an asteroid. For a long time, scientists believed that the asteroid responsible for wiping out the dinosaurs and many other species was solely to blame for the mass extinction. The recent study challenges that decades-long theory, suggesting that additional asteroid impacts may have played a role in the catastrophic events of that era.
