About 466 million years ago, somewhere between Mars and Jupiter, a monster collision led to the disintegration of an asteroid and created a cloud of dust that would sweep the solar system, and impact the life on Earth.
This event, which took place tens of millions of kilometers from the blue planet, plunged it into an era of ice and triggered a real explosion of primitive life, says an international team of scientists in works published in the journal Science Advances.
An atmosphere saturated with dust
There has always been extraterrestrial dust in the Earth’s atmosphere. Today, however, this dust is only a tiny fraction of the fine particles in suspension, among volcanic ash, desert dust and salt from the oceans.
But when a 150-km-wide asteroid broke up in the main asteroid belt during the Ordovician, the geological era stretched from -488.3 to -443.7 million years, the cataclysmic phenomenon has created much more dust than usual.
It’s as if you stand in the middle of your living room and blow up your vacuum bag, but on an astronomical scale!
Dr. Birger Schmitz, an expert in nuclear physics at Lund University in Sweden, says that this mass of airborne material has blocked some of the light that usually reaches the earth’s surface.
The phenomenon caused a drop in temperatures leading to a small ice age for at least 2 million years.
Life has adapted
This cooling lasted so long that a large number of living species that were not in the warmer regions near the equator had to adapt. They have evolved to make the most of the newly emerging cold regions on the planet, which was already cooling down at that time.
It must be known that the acceleration of the temperature drop has turned more water into ice over a large part of the planet, even causing a drop in sea level.
The cooling caused by asteroid dust was still gradual enough for life to adapt and even benefit from the changes. New species have developed in regions with different temperatures.
This is the first time we show that dust from the disintegration of a distant asteroid can cause cooling on Earth, and even trigger an ice age.
Birger Schmitz, Lund University
Our work provides a more detailed and empirical understanding of how this works, knowledge that can be used to evaluate our simulations of current models , Birger Schmitz concludes.
A planet, a universe
In recent decades, scientists have begun to understand that the evolution of life on Earth also depends on astronomical events.
The best-known example is without a doubt the impact of an asteroid 10 km wide 66 million years ago that led to the disappearance of dinosaurs almost instantly.