The rupture of a large asteroid filled the entire internal solar system with enormous amounts of dust that led to a unique ice age and, subsequently, to higher levels of biodiversity, researchers from Lund University have concluded.
This unexpected discovery, published in Science Advances, could be relevant to address global warming if we fail to reduce carbon dioxide emissions. In recent decades, researchers have begun to understand that the evolution of life on Earth also depends on astronomical events.
An example of this is when dinosaurs were instantly eliminated by the Cretaceous-Paleogenic impact of a 10-kilometer asteroid.
For the first time, scientists can now present another example of how an extraterrestrial event formed life on Earth.
470 million years ago, a 150 kilometer asteroid between Jupiter and Mars was crushed, and the dust spread through the solar system.
The climate changed from being more or less homogeneous to being divided into climatic zones, from arctic conditions at the poles to tropical conditions in the equator.
The great diversity among invertebrates occurred as an adaptation to the new climate, triggered by the exploded asteroid. “It’s analogous to standing in the middle of the living room and breaking a vacuum bag, only on a much larger scale,” exemplifies Birger Schmitz, a professor of geology at Lund University and leader of the study.
An important method that led to the discovery was the measurement of extraterrestrial helium incorporated into the sediments of the petrified seabed in Kinnekulle, in southern Sweden.
On its way to Earth, the dust was enriched with helium when it was bombarded by the solar wind. “This result was completely unexpected. For the past 25 years we have relied on very different hypotheses in terms of what happened. It was not until we got the last helium measurements that everything fit together,” Birger Schmitz recalls in a statement.
The global warming continues as a result of emissions of carbon dioxide and the temperature rise is greater at high latitudes.
According to the Intergovernmental Panel on Climate Change, we are approaching a situation that recalls the conditions that prevailed before the asteroid collision 470 million years ago.
In the last decade or so, researchers have discussed different artificial methods to cool the Earth in case of a major climatic catastrophe.
The modelers have shown that it would be possible to place asteroids, like satellites, in orbits around the Earth in such a way that they continuously release fine dust and, therefore, partially block the warm sunlight.
“Our results show for the first time that dust has sometimes cooled the Earth drastically. Our studies can provide a more detailed and empirical understanding of how this works, and this in turn can be used to assess whether model simulations are realistic.” concludes Birger Schmitz.