Scientists have revealed that the dinosaurs were not made extinct by an asteroid colliding with earth.
A team of experts, led by the Royal Observatory of Belgium, have determined that debris from the asteroid was thrown into the earth’s atmosphere, blocking the light of the sun thereby preventing the process of photosynthesis needed for plants to survive.
The amount of dust generated, the experts believe, was approximately 2,000 gigatonnes. That’s 11 times the weight of Mount Everest.
The dust is said to have lingered in the atmosphere for as long as 15 years, causing a global nuclear winter.
The lack of sunlight would have prevented the survival of plants and as a result herbivores would have died out too. Many herbivores were dinosaurs and scientists believe this protracted period without sunlight explains their extinction.
Such was the scale of the natural catastrophe that 75 percent of living creatures on earth are believed to have been wiped out by the long winter.
Scientists had been stumped by the mystery of the dinosaur extinction, following the discovery of the Chicxulub Crater in 1978.
However, the giant asteroid and the 110-mile crater it left was not sufficient to conclude that that’s what made the dinosaurs extinct.
The previous theory was that sulphur from the impact of the asteroid, or soot from the global fires it created, blocked the light of the sun and condemned the planet to a long painful winter.
However the new findings point to the dust from the asteroid being responsible for the prolonged lightless period.
The dust particles scientists analysed were located at the Tanis fossil site in the US state of North Dakota.
University of Texas geophysicist Sean Gulick, who was not involved in the research, told AFP that the study was yet another interesting attempt to answer the “hot question” of what drove the impact of nuclear winter. However he pointed out that it did not give a definitive answer.
He said that understanding the extinction events of the past may be useful in understanding future extinction threats.
Gulick added: “Maybe we can better predict our own mass extinction that we’re probably in the middle of”.
